Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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AEROSOL-GENERAT1NG ELEMENT FOR USE IN AN AEROSOL-GENERATING
ARTICLE OR SYSTEM
The present invention relates to an aerosol-generating element which finds
particular
use in an aerosol-generating article or system. The present invention further
relates to an
aerosol-generating article or system comprising such an aerosol-generating
element.
Aerosol-generating articles in which an aerosol-generating substrate, such as
a tobacco-
containing substrate, is heated rather than combusted, are known in the art.
Typically in such
articles an aerosol is generated by the transfer of heat from a heat source to
a physically
separate aerosol-generating substrate or material, which may be located in
contact with,
within, around, or downstream of the heat source. During use of the aerosol-
generating article,
volatile compounds are released from the aerosol-generating substrate by heat
transfer from
the heat source and are entrained in air drawn through the aerosol-generating
article. As the
released compounds cool, they condense to form an aerosol.
A number of prior art documents disclose aerosol-generating devices for
consuming
aerosol-generating articles. Such devices include, for example, electrically
heated aerosol-
generating devices in which an aerosol is generated by the transfer of heat
from one or more
electrical heater elements of the aerosol-generating device to the aerosol-
generating
substrate of a heated aerosol-generating article.
Substrates for heated aerosol-generating articles have, in the past, often
been produced
using randomly oriented shreds, strands, or strips of tobacco material. As an
alternative, rods
for heated aerosol-generating articles formed from gathered sheets of tobacco
material have
been disclosed, by way of example, in international patent application VVO
2012/164009.
International patent application WO 2011/101164 discloses alternative rods for
heated
aerosol-generating articles formed from strands of homogenised tobacco
material, which may
be formed by casting, rolling, calendering or extruding a mixture comprising
particulate
tobacco and at least one aerosol former to form a sheet of homogenised tobacco
material. In
alternative embodiments, the rods of WO 2011/101164 may be formed from strands
of
homogenised tobacco material obtained by extruding a mixture comprising
particulate tobacco
and at least one aerosol former to form continuous lengths of homogenised
tobacco material.
Substrates for heated aerosol-generating articles typically further comprise
an aerosol
former, that is, a compound or mixture of compounds that, in use, facilitates
formation of the
aerosol and that preferably is substantially resistant to thermal degradation
at the operating
temperature of the aerosol-generating article. Examples of suitable aerosol-
formers include,
but are not limited to: polyhydric alcohols, such as propylene glycol,
triethylene glycol, 1,3-
butanediol and glycerin; esters of polyhydric alcohols, such as glycerol mono-
, di- or triacetate;
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and aliphatic esters of mono-, di- or polycarboxylic acids, such as dimethyl
dodecanedioate
and dimethyl tetradecanedioate.
Alternative forms of substrates comprising nicotine have also been disclosed.
By way
of example, liquid nicotine compositions, often referred to as e-liquids, have
been proposed.
These liquid compositions may, for example, be heated by a coiled electrically
resistive
filament of an aerosol-generating device.
Substrates of this type may require particular care in the manufacture of the
containers
holding the liquid composition in order to prevent undesirable leakages.
It has been previously proposed to provide an encapsulated nicotine
formulation for use
as an aerosol-generating substrata However, the encapsulation of nicotine
formulations has
been found to be challenging. One of the reasons for this is the preference
for hydrophilic
aerosol formers, such as glycerin and propylene glycol, in the nicotine
formulation, which
makes it difficult to use many of the commonly used encapsulation materials,
which are also
hydrophilic. With existing encapsulation techniques, it has generally been
found that such a
high level of the hydrophilic encapsulation material is required in order to
produce a stable
product that an insufficient payload of the nicotine formulation is provided.
Whilst hydrophobic encapsulation materials are available, such materials often
need to
be processed at relatively high temperature, which risks the degradation of
the nicotine
formulation during manufacture. During use, the temperatures required to
generate an
aerosol from the nicotine formulation may be sufficiently high to cause
degradation of the
hydrophobic encapsulation material. This may result in the release of
undesirable compounds
into the resultant aerosol, which may have an adverse impact on the sensory
profile of the
aerosol.
It has also been proposed to provide a gel composition comprising nicotine
that is
adapted to generate a nicotine-containing aerosol upon heating. By way of
example, WO
2018/019543 discloses a thermoreversible gel composition, that is, a gel that
becomes fluid
when heated to a melting temperature and sets into a gel again at a gelation
temperature.
WO 2018/019543 discloses the provision of such a gel within a housing of a
cartridge. The
cartridge can be disposed of and replaced when the gel has been consumed. In
order for the
gel composition to generate a satisfactory amount of aerosol during use, it is
desirable for the
gel composition to include a significant amount of an aerosol-former, such as
glycerol.
However, due to the plasticising qualities of glycerol, it has been difficult
to provide a gel
composition that is capable of providing a good aerosol delivery during use
and, at the same
time, geometrically stable, that is, a gel composition that does not undergo a
significant volume
loss as it solidifies and settles into film form.
Thus, it would be desirable to provide an alternative, novel encapsulated
aerosol-
generating formulation, such as for example an aerosol-generating element
encapsulating a
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nicotine-containing formulation, which provides an improved encapsulated
substrate having
increased stability and minimal leakage of the aerosol-generating formulation.
It would also be desirable to provide such an aerosol-generating element that
is easy to
handle such as to facilitate the manufacturing and packaging of aerosol-
generating articles
comprising one or more of the aerosol-generating element It would also be
desirable to
provide such an encapsulated aerosol-generating formulation with minimal
encapsulating
structure, so as to provide an efficient aerosol delivery, particularly when
heated to a
temperature in the range from about 150 degrees Celsius to about 350 degrees
Celsius.
The present disclosure relates to an aerosol-generating element for use in an
aerosol-
generating article or system. The aerosol-generating element may comprise a
solid
continuous matrix structure and an aerosol-generating formulation dispersed
within the solid
continuous matrix structure. The aerosol-generating formulation may be trapped
within the
solid continuous matrix structure and releasable from the solid continuous
matrix structure
upon heating of the aerosol-generating element The solid continuous matrix
structure may
be a polymer matrix comprising one or more matrix-forming polymers. The
aerosol-generating
formulation dispersed within the solid continuous matrix structure may
comprise at least one
alkaloid or cannabinoid compound. The aerosol-generating formulation dispersed
within the
solid continuous matrix structure may comprise a polyhydric alcohol. The
polyhydric alcohol
may account for at least 30 percent by weight based on the total weight of the
aerosol-
generating element.
Further, the present disclosure relates to an aerosol-generating article
comprising one
or more aerosol-generating elements as described above. In addition, the
present disclosure
relates to an aerosol-generating system comprising one or more aerosol-
generating elements
or an aerosol-generating article as described above and an electrically
operated aerosol-
generating device comprising a heating element and a heating chamber
configured to receive
the aerosol-generating element or article so that the aerosol-generating
element is heated in
the heating chamber by the heating element.
According to the present invention there is provided an aerosol-generating
element for
use in an aerosol-generating article or system, the aerosol-generating element
comprising: a
solid continuous matrix structure; and an aerosol-generating formulation
dispersed within the
solid continuous matrix structure, wherein the aerosol-generating formulation
is trapped within
the solid continuous matrix structure and releasable from the solid continuous
matrix structure
upon heating of the aerosol-generating element; wherein the solid continuous
matrix structure
is a polymer matrix comprising one or more matrix-forming polymers, and
wherein the aerosol-
generating formulation dispersed within the solid continuous matrix structure
comprises at
least one alkaloid or cannabinoid compound and a polyhydric alcohol, wherein
the polyhydric
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alcohol accounts for at least 30 percent by weight based on the total weight
of the aerosol-
generating element.
The term "aerosol-generating article" is used herein with reference to the
invention to
describe an article wherein an aerosol-generating substrate is heated to
produce and deliver
an aerosol to a consumer. As used herein, the term "aerosol-generating
substrate" denotes
a substrate capable of releasing volatile compounds upon heating to generate
an aerosol.
The term "aerosol-generating element' is used herein with reference to the
invention to
describe a discrete, self-standing aerosol-generating substrate element
capable of releasing
volatile compounds upon heating to generate an aerosol.
The aerosol generated from the aerosol-generating formulation of aerosol-
generating
elements described herein is a dispersion of solid particles or liquid
droplets (or a combination
of solid particles and liquid droplets) in a gas. The aerosol may be visible
or invisible and may
include vapours of substances that are ordinarily liquid or solid at room
temperature as well
as solid particles or liquid droplets or a combination of solid particles and
liquid droplets.
An aerosol-generating element in accordance with the present invention may
find use
as an aerosol-generating substrate of an aerosol-generating article.
A conventional cigarette is lit when a user applies a source of ignition to
one end of the
cigarette and draws air through the other end. The localised heat provided by
the flame and
the oxygen in the air drawn through the cigarette causes the end of the
cigarette to ignite, and
the resulting combustion generates an inhalable smoke. By contrast, in heated
aerosol-
generating articles, an aerosol is generated by heating a flavour generating
substrate, such
as, for example, a tobacco-based substrate or a substrate containing an
aerosol-former and
a flavouring. Known heated aerosol-generating articles include, for example,
electrically
heated aerosol-generating articles and aerosol-generating articles in which an
aerosol is
generated by the transfer of heat from a combustible fuel element or heat
source to a
physically separate aerosol forming material.
For example, aerosol-generating articles according to the invention may find
particular
application in aerosol-generating systems comprising an electrically heated
aerosol-
generating device having an internal heater which is adapted to supply heat to
one or more
discrete aerosol-generating substrate elements. As used herein with reference
to the present
invention, the term "aerosol-generating device" is used to describe a device
comprising a
heater element that interacts with one or more aerosol-generating elements in
accordance
with the invention to produce an aerosol. During use, volatile compounds are
released from
the aerosol-generating element or elements by heat transfer and entrained in
air drawn
through the aerosol-generating article. As the released compounds cool they
condense to
form an aerosol that is inhaled by the consumer.
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Substrates for heated aerosol-generating articles typically comprise an
"aerosol formers,
that is, a compound or mixture of compounds that, in use, facilitates
formation of the aerosol,
and that preferably is substantially resistant to thermal degradation at the
operating
temperature of the aerosol-generating article. Examples of suitable aerosol-
formers include:
polyhydric alcohols, such as propylene glycol, triethylene glycol, 1,3-
butanediol and glycerin;
esters of polyhydric alcohols, such as glycerol mono-, di- or triacetate; and
aliphatic esters of
mono-, di- or polycarboxylic adds, such as dimethyl dodecanedioate and
dimethyl
tetradecanedioate. The polyhydric alcohol in the aerosol-generating article of
the invention is
also an aerosol former within the meaning set out above.
As used herein with reference to the present invention, the term "aerosol-
generating
formulation" refers to a formulation comprising a plurality of aerosol-
generating formulation
components, which upon heating of the aerosol-generating element will
volatilise to produce
an aerosol.
As used herein with reference to the present invention, the term "matrix-
forming
polymer" refers to an encapsulation material in the form of a polymer which is
capable of
producing a three-dimensional polymer matrix as a result of cross-linking when
the matrix-
forming polymer is brought into contact with a cross-linking solution of
multivalent cations. The
resultant polymer matrix is capable of trapping and retaining the aerosol-
generating
formulation within its cross-linked structure. The nature of the cross-linked
polymer matrix will
be discussed in more detail below.
As briefly described above, in contrast with existing aerosol-generating
elements, an
aerosol-generating element in accordance with the present invention comprises
a solid
continuous matrix structure and an aerosol-generating formulation dispersed
within the solid
continuous matrix structure. In more detail, the aerosol-generating
formulation is trapped
within the solid continuous matrix structure and can be released from the
solid continuous
matrix structure upon heating of the aerosol-generating element to a
predetermined
temperature.
VVithout wishing to be bound by theory, it is understood that in an aerosol-
generating
element in accordance with the present invention a three-dimensional polymeric
matrix
structure is formed by cross-linking, and aerosol-generating formulation is
retained within the
polymeric matrix structure. This is, in particular, in contrast with existing
core/shell structures
wherein a content of the core is released upon rupturing the shell.
In an aerosol-generating element in accordance with the present invention the
solid
continuous matrix structure is a polymer matrix comprising one or more matrix-
forming
polymers. Further, the aerosol-generating formulation dispersed within the
solid continuous
matrix structure comprises at least one alkaloid or cannabinoid compound, and
at least 30
percent by weight of a polyhydric alcohol.
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Advantageously, the invention enables the provision of an aerosol-generating
formulation in encapsulated form that has a significantly lower content of
encapsulation
material (corresponding to the one or more matrix-forming polymers of the
solid continuous
matrix structure) compared with previously available substrates. As such, the
levels of the
aerosol-generating formulation components, such as the alkaloid or cannabinoid
and the
polyhydric alcohol, can advantageously be maximised within the aerosol-
generating element
Further, the reduction in the proportion of encapsulation material required
enables a more
efficient generation of aerosol upon heating, since less of the heat supplied
to the aerosol-
generating element is used for increasing the temperature of the encapsulation
material_
The polymer-based solid continuous matrix of aerosol-generating articles in
accordance
with the present invention provides an inert encapsulation structure for
retaining and
immobilising the aerosol-generating formulation, which is stable upon heating
of the aerosol-
generating element during use. The inventors have found that, when heated to
temperatures
in the range from 150 degrees Celsius to 350 degrees Celsius, aerosol-
generating elements
in accordance with the present invention release an aerosol as they undergo a
significant
weight loss. This weight loss is not, however, accompanied by an equally
significant volume
loss. Without wishing to be bound by theory, it is understood that upon
heating, components
of the aerosol-generating formulation originally dispersed and trapped within
the solid
continuous matrix structure are substantially vaporised and released. On the
other hand,
components of the solid continuous matrix are substantially unaffected and the
solid
continuous matrix only partially shrinks while essentially retaining its 3D
structure. As such,
the encapsulation of the aerosol-generating formulation within the polymer-
based matrix
advantageously provides minimal or no adverse effects on the sensory profile
of the aerosol
generated upon heating.
The aerosol-generating element of the present invention has been found to
advantageously provide a controlled delivery of aerosol. Furthermore, the
aerosol delivery
profile can be readily adjusted by adjusting parameters of the aerosol-
generating element such
as the size, shape, structure and formulation of the aerosol-generating
element.
The invention advantageously provides an aerosol-generating element that is in
the form
of a discrete, self-standing solid object which is sufficiently stable and
robust that it can readily
be processed and introduced into an aerosol-generating article using existing
methods and
techniques.
Further, aerosol-generating elements in accordance with the present invention
can be
prepared by a cost-effective method that can be carried out with existing
equipment, as will
become apparent from the following description thereof. In addition, aerosol-
generating
elements in accordance with the present invention can be prepared by a method
that can be
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easily incorporated into existing production lines for the manufacture of
aerosol-generating
articles.
Aerosol-generating elements in accordance with the present invention may be
prepared
from a matrix precursor solution and components of an aerosol-generating
formulation. By
way of example, in a method of manufacturing an aerosol-generating element in
accordance
with the invention, a matrix precursor solution may be provided that comprises
a matrix-
forming polymer in water. Preferably, the matrix polymer solution comprises at
least about 35
percent by weight of water, more preferably at least about 40 percent by
weight of water.
This level of water ensures that the matrix-forming polymer is sufficiently
dissolved so that a
homogeneous solution is provided.
The matrix-forming polymer may be a single polymer or a combination of two or
more
polymers, wherein the one or more polymers are capable of forming a cross-
linked matrix
through an ionotropic gelation mechanism in a cross-linking solution of
multivalent cations.
The cross-linking of the matrix-forming polymer is achieved through reaction
of the polymer
with multivalent cations in the cross-linking solution, which form salt
bridges to cross-link the
polymer molecules. Suitable matrix-forming polymers would be known to the
skilled person,
and include, but are not limited to, alginate, pectin, hydroxyethylmethacryate
(HEMA), N-(2-
hydroxy propypmethacrylate (HPMA), N-vinyl-2-pyrrolidone (NVP), N-
isopropylacrylamide
(NIPAMM), vinyl acetate (VAc), acrylic acid (AA), methacrylic acid (MAA),
polyethylene glycol
acrylate/rnethaaylate (PEGA/PEGMA) and polyethylene glycol
diacrylate/dimethacrylate,
(PEGDA/PEG DMA).
Preferably, the matrix-forming polymer comprises one or more polysaccharides,
such
as alginate or pectin, or a combination thereof. Partiesilarly'preferably;i
theimatitoorming
polymer. ............... is-sigma* Polysaccharides are particularly suitable
for use in the present invention,
since they can be made water insoluble and heat stable through cross-linking,
and are
tasteless. There is therefore no adverse impact on the sensory properties of
the aerosol
generated from the aerosol-generating element. Alternative matrix-forming
polymers suitable
for use in methods according to the invention include but are not limited to
chitosan, fibrin,
collagen, gelatin, hyaluronic acid, dextran and combinations thereof.
In preferred embodiments, the matrix-forming polymer is a single
polysaccharide.
Even more preferably the matrix-forming polymer is alginate. In other words,
in such
particularly preferred embodiments, the solid continuous matrix structure is
an alginate
polymer matrix.
In a first step, a plurality of aerosol-generating formulation components may
be added
to the matrix precursor solution to form an aerosol-generating solution,
wherein the aerosol-
generating formulation components comprise at least one alkaloid or
cannabinoid compound
and a polyhydric alcohol. As used herein when describing a method of preparing
aerosol-
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generating elements in accordance with the invention, the term "aerosol-
generating solution"
denotes a solution of the aerosol-generating formulation components and the
matrix
precursors, in an appropriate solvent.
Polyhydric alcohols suitable for use in the aerosol-generating element
include, but are
not limited to, propylene glycol, triethylene glycol, 1,3-butanediol, and
glycerin. Preferably, in
an aerosol-generating element produced in accordance with the invention the
polyhydric
alcohol is selected from the group consisting of glycerin, propylene glycol,
and combinations
thereof. In particularly preferred embodiments the polyhydric alcohol is
glycerin. Preferably,
the alkaloid is selected from the group consisting of: nicotine, anatabine and
combinations
thereof.
It may be desirable to control the viscosity of aerosol-generating solution.
This may
include controlling the viscosity of the matrix polymer solution as the
aerosol-generating
formulation components are added. For example, depending upon the technique
used for
producing the discrete portion of the aerosol-generating solution in the
subsequent step of the
method, it may be preferable to provide the aerosol-generating solution with a
viscosity within
a specific range. Different techniques are likely to be facilitated by
different viscosity solutions
and an appropriate viscosity should therefore be determined depending upon the
technique
used. By way of example, when the discrete portion of the aerosol-generating
solution is
produced in a gravitational dripping process, the viscosity of the solution is
preferably retained
below about 5000 mPa.s. (rnilliPascal-seconds). This enables droplets of the
aerosol-
generating solution to be formed under gravity and also allows the beads to
reach a stable
shape in the cross-linking solution before the cross-linking hardens the
solution and fixes the
final shape of the aerosol-generating element.
In certain cases, in order to control the viscosity of the aerosol-generating
solution it may
be preferably to control the pH of the matrix polymer solution whilst the
aerosol-generating
formulation components are being added. This is because for some matrix
polymer solutions,
the pH may affect the viscosity. For example, in embodiments of the invention
in which the
matrix-forming polymer comprises alginate, it is preferable to retain the pH
of the solution
above pH4. This is intended to avoid any gelling of the alginate, which may
occur at pH levels
below pH4, for example, due to hydrogen bonding. Such gelling at a low pH
would cause an
undesirable increase in the viscosity of the aerosol-generating solution,
which would make it
difficult to use certain techniques such as gravitational dripping, in order
to form the aerosol-
generating element.
Alternatively or in addition, the viscosity of the aerosol-generating solution
may be
controlled by adjusting the concentration of the solution. For example, the
proportion of water
in the aerosol-generating solution may be adjusted in order to adjust the
viscosity. Preferably,
the aerosol-generating solution comprises at least about 35 percent by weight
of water in order
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to maintain a suitable viscosity. Particularly preferably, the aerosol-
generating solution
comprises between about 35 percent by weight and about 65 percent by weight of
water. A
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In a second step, a discrete portion of the aerosol-generating solution may be
formed.
In a third step, the formed discrete portion of the aerosol-generating
solution may be added to
a cross-linking solution of multivalent cations to cross-link the matrix-
forming polymer, thereby
forming an aerosol-generating element having a continuous polymer matrix
structure and an
aerosol-generating formulation comprising the aerosol-generating components
dispersed
within the continuous polymer matrix. Preferred multivalent cations include
calcium, iron,
aluminium, manganese, copper, zinc or lanthanum. A particularly preferred salt
is calcium
chloride.
In certain preferred embodiments of the invention in which the aerosol-
generating
solution comprises an acid, the calcium salt provided in the cross-linking
solution may
advantageously be a salt of the same acid. For example, in embodiments in
which the aerosol-
generating solution comprises lactic acid, the cross-linking solution may
advantageously
comprise calcium lactate.
Where the aerosol-generating solution comprises nicotine, the acid in the
aerosol-
generating solution forms a nicotine salt with the nicotine. The use of a
calcium salt
corresponding to the acid in the aerosol-generating solution therefore
provides the same salt
in the cross-linking solution as in the aerosol-generating solution.
This, in turn,
advantageously limits the diffusion of nicotine salts out of the aerosol-
generating solution into
the cross-linking solution during the cross-linking step. A higher
concentration of the nicotine
salt can therefore be retained within the aerosol-generating element
Furthermore, any
potential waste of the nicotine and acid during the production of the aerosol-
generating
element can be reduced.
Preferably, the cross-linking solution further comprises a polyhydric alcohol,
which is
the same as the polyhydric alcohol selected as the aerosol-generating
formulation component
The inclusion of the polyhydric alcohol in the cross-linking solution has been
found to limit
diffusion of the polyhydric alcohol from the aerosol-generating solution into
the cross-linking
solution during the cross-linking step. This advantageously enables a higher
concentration of
the polyhydric alcohol to be retained within the aerosol-generating element
than has been
previously possible.
In a fourth step, the aerosol-generating element may be removed from the cross-
linking
solution and dried.
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As described briefly above, in aerosol-generating elements in accordance with
the
present invention, the solid continuous matrix structure is a polymer matrix
comprising one or
more matrix-forming polymers. Suitable matrix-forming polymers would be known
to the
skilled person.
Preferably, the one or more matrix-forming polymer include one or more
polysaccharides. More preferably, the one or more matrix-forming polymers
include at least
one of alginate and pectin.
Polysaccharides are particularly suitable for use in the present invention,
since they can
be made water insoluble and heat stable through cross-linking, and are
tasteless. There is
therefore no adverse impact on the sensory properties of the aerosol generated
from the
aerosol-generating element.
In preferred embodiments, the matrix-forming polymer is a single
polysaccharide. Even
more preferably the matrix-forming polymer is alginate. In other words, in
such particularly
preferred embodiments, the solid continuous matrix structure is an alginate
polymer matrix.
Use of alginate as the sole matrix-forming polymer is preferred because
alginate has the
ability to promote the rapid formation of insoluble, solid aerosol-generating
elements. In more
detail, the inventors have found that use of alginate as the sole matrix-
forming polymer,
particularly in the amounts described below, advantageously provides aerosol-
generating
elements that are stable and self-supporting and can hold higher
concentrations of polyhydric
alcohol within the polymer matrix. Further, compared to other formulations,
use of alginate as
the sole matrix-forming polymer, particularly in the amounts described below
has been found
to allow for larger aerosol-generating elements to be formed ¨ for example, in
the form of
spherical or quasi-spherical beads having larger diameters.
Preferably, in an aerosol-generating element in accordance with the present
invention,
the solid continuous matrix structure is an alginate polymer matrix and the
aerosol-generating
element comprises at least about 1 percent by weight of alginate. More
preferably, the
aerosol-generating element comprises at least about 1.5 percent by weight of
alginate. Even
more preferably, the aerosol-generating element comprises at least about 2
percent by weight
of alginate.
In particularly preferred embodiments, the aerosol-generating element
comprises at
least about 3 percent by weight of alginate.
Preferably, in an aerosol-generating element in accordance with the present
invention,
the solid continuous matrix structure is an alginate polymer matrix and the
aerosol-generating
element comprises less than or equal to about 10 percent by weight of
alginate. More
preferably, the aerosol-generating element comprises less than or equal to
about 8 percent
by weight of alginate. Even more preferably, the aerosol-generating element
comprises less
than or equal to about 6 percent by weight of alginate.
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In particularly preferred embodiments, the aerosol-generating element
comprises less
than or equal to about 5 percent by weight of alginate.
In some embodiments, the solid continuous matrix structure is an alginate
polymer
matrix and the aerosol-generating element comprises from about 1 percent by
weight to about
percent by weight of alginate. Preferably, the aerosol-generating element
comprises from
about 1.5 percent by weight to about 10 percent by weight of alginate, more
preferably from
about 2 percent by weight to about 10 percent by weight of alginate, even more
preferably
from about 3 percent by weight to about 10 percent by weight of alginate.
In other embodiments, the solid continuous matrix structure is an alginate
polymer matrix
and the aerosol-generating element comprises from about 1 percent by weight to
about 8
percent by weight of alginate. Preferably, the aerosol-generating element
comprises from
about 1.5 percent by weight to about 8 percent by weight of alginate, more
preferably from
about 2 percent by weight to about 18 percent by weight of alginate, even more
preferably
from about 3 percent by weight to about 8 percent by weight of alginate.
In further embodiments, the solid continuous matrix structure is an alginate
polymer
matrix and the aerosol-generating element comprises from about 1 percent by
weight to about
6 percent by weight of alginate. Preferably, the aerosol-generating element
comprises from
about 1.5 percent by weight to about 6 percent by weight of alginate, more
preferably from
about 2 percent by weight to about 6 percent by weight of alginate, even more
preferably from
about 3 percent by weight to about 6 percent by weight of alginate.
Alternative matrix-forming polymers suitable for use in aerosol-generating
elements in
accordance with the invention include, but are not limited to, chitosan,
fibrin, collagen, gelatin,
hyaluronic acid, dextran and combinations thereof.
Further alternative matrix-forming polymers suitable for use in aerosol-
generating
elements in accordance with the invention may be built from one or more of the
following
monomers and polymers:
hydroxyethylmethacryate (H EMA), N-(2-
hydroxy
propyl)methacrylate (HPMA), N-vinyl-2-pyrrolidone (NVP), N-isopropylacrylamide
(NI PAMM),
vinyl acetate (VAc), acrylic acid (AA), methacrylic acid (MAA), polyethylene
glycol
acrylate/nnethacrylate (PEGA/PEGMA) and polyethylene glycol
diacrylate/dirnethacrylate,
(PEGDA/PEG DMA).
As defined above, an aerosol-generating element in accordance with the
invention
comprises a polyhydric alcohol as a component of the aerosol-generating
formulation
dispersed within the solid continuous matrix structure. In more detail, the
polyhydric alcohol
content in the aerosol-generating formulation accounts for at least 30 percent
by weight based
on the total weight of the aerosol-generating element
The polyhydric alcohol acts as the aerosol former of the aerosol-generating
element.
Polyhydric alcohols suitable for use in the aerosol-generating element
include, but are not
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limited to, propylene glycol, triethylene glycol, 1,3-butanediol, and
glycerin. Preferably, in an
aerosol-generating element in accordance with the invention the polyhydric
alcohol is selected
from the group consisting of glycerin, propylene glycol, and combinations
thereof. In
particularly preferred embodiments the polyhydric alcohol is glycerin.
Preferably, the polyhydric alcohol content in the aerosol-generating
formulation
accounts for at least about 35 percent by weight based on the total weight of
the aerosol-
generating element. Thus, an aerosol-generating element in accordance with the
present
invention comprises at least about 35 percent by weight of the polyhydric
alcohol.
Even more preferably, the polyhydric alcohol content in the aerosol-generating
formulation accounts for at least 40 percent by weight based on the total
weight of the aerosol-
generating element. As such, an aerosol-generating element in accordance with
the present
invention comprises at least about 40 percent by weight of the polyhydric
alcohol.
In particularly preferred embodiments, the polyhydric alcohol content in the
aerosol-
generating formulation accounts for at least about 45 percent by weight based
on the total
weight of the aerosol-generating element. More preferably, the polyhydric
alcohol content in
the aerosol-generating formulation accounts for at least about 50 percent by
weight based on
the total weight of the aerosol-generating element Even more preferably, the
polyhydric
alcohol content in the aerosol-generating formulation accounts for at least
about 55 percent
by weight based on the total weight of the aerosol-generating element. Most
preferably, the
polyhydric alcohol content in the aerosol-generating formulation accounts for
at least about 60
percent by weight or at least about 65 percent by weight or at least about 70
percent by weight
based on the total weight of the aerosol-generating element
Typically, in an aerosol-generating element in accordance with the invention
the
polyhydric alcohol content in the aerosol-generating formulation accounts for
less than or
equal to about 95 percent by weight based on the total weight of the aerosol-
generating
element.
Preferably, in an aerosol-generating element in accordance with the invention
the
polyhydric alcohol content in the aerosol-generating formulation accounts for
less than or
equal to about 90 percent by weight based on the total weight of the aerosol-
generating
element. More preferably, the polyhydric alcohol content in the aerosol-
generating formulation
accounts for less than or equal to about 85 percent by weight based on the
total weight of the
aerosol-generating element. Even more preferably, the polyhydric alcohol
content in the
aerosol-generating formulation accounts for less than or equal to about 80
percent by weight
based on the total weight of the aerosol-generating element
In some embodiments, the polyhydric alcohol content in the aerosol-generating
formulation accounts for from about 30 percent by weight to about 95 percent
by weight based
on the total weight of the aerosol-generating element Preferably, the
polyhydric alcohol
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content in the aerosol-generating formulation accounts for from about 35
percent by weight to
about 95 percent by weight based on the total weight of the aerosol-generating
element. More
preferably, the polyhydric alcohol content in the aerosol-generating
formulation accounts for
from about 40 percent by weight to about 95 percent by weight based on the
total weight of
the aerosol-generating element. Even more preferably, the polyhydric alcohol
content in the
aerosol-generating formulation accounts for from about 45 percent by weight to
about 95
percent by weight based on the total weight of the aerosol-generating element.
In particularly
preferred embodiments, the polyhydric alcohol content in the aerosol-
generating formulation
accounts for from about 50 percent by weight to about 95 percent by weight
based on the total
weight of the aerosol-generating element, more preferably from about 55
percent by weight to
about 95 percent by weight based on the total weight of the aerosol-generating
element, even
more preferably from about 60 percent by weight to about 95 percent by weight
based on the
total weight of the aerosol-generating element. In most preferred embodiments,
the polyhydric
alcohol content in the aerosol-generating formulation accounts for from about
65 percent by
weight to about 95 percent by weight or even from about 70 percent by weight
to about 95
percent by weight based on the total weight of the aerosol-generating element.
In these embodiments, the aerosol-generating element may comprise from about
30
percent by weight to about 95 percent by weight of polyhydric alcohol and
preferably from
about 35 percent by weight to about 95 percent by weight of polyhydric
alcohol. More
preferably, the aerosol-generating element comprises from about 40 percent by
weight to
about 95 percent by weight of polyhydric alcohol. Even more preferably, the
aerosol-
generating element comprises from about 45 percent by weight to about 95
percent by weight
of polyhydric alcohol. In particularly preferred embodiments, the aerosol-
generating element
comprises from about 50 percent by weight to about 95 percent by weight of
polyhydric
alcohol, preferably from about 55 percent by weight to about 95 percent by
weight of polyhydric
alcohol, more preferably from about 60 percent by weight to about 95 percent
by weight of
polyhydric alcohol, even more preferably from about 65 percent by weight to
about 95 percent
by weight of polyhydric alcohol, most preferably from about 70 percent by
weight to about 95
percent by weight of polyhydric alcohol.
In other embodiments, the polyhydric alcohol content in the aerosol-generating
formulation accounts for from about 30 percent by weight to about 90 percent
by weight based
on the total weight of the aerosol-generating element. Preferably, the
polyhydric alcohol
content in the aerosol-generating formulation accounts for from about 35
percent by weight to
about 90 percent by weight based on the total weight of the aerosol-generating
element. More
preferably, the polyhydric alcohol content in the aerosol-generating
formulation accounts for
from about 40 percent by weight to about 90 percent by weight based on the
total weight of
the aerosol-generating element. Even more preferably, the polyhydric alcohol
content in the
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aerosol-generating formulation accounts for from about 45 percent by weight to
about 90
percent by weight based on the total weight of the aerosol-generating element.
In particularly
preferred embodiments, the polyhydric alcohol content in the aerosol-
generating formulation
accounts for from about 50 percent by weight to about 90 percent by weight
based on the total
weight of the aerosol-generating element, more preferably from about 55
percent by weight to
about 90 percent by weight based on the total weight of the aerosol-generating
element, even
more preferably from about 60 percent by weight to about 90 percent by weight
based on the
total weight of the aerosol-generating element. In most preferred embodiments,
the polyhydric
alcohol content in the aerosol-generating formulation accounts for from about
65 percent by
weight to about 90 percent by weight or even from about 70 percent by weight
to about 90
percent by weight based on the total weight of the aerosol-generating element.
In these embodiments, the aerosol-generating element in accordance with the
present
invention may comprise from about 30 percent by weight to about 90 percent by
weight of a
polyhydric alcohol. Preferably, the aerosol-generating element comprises from
about 35
percent by weight to about 90 percent by weight of polyhydric alcohol. More
preferably, the
aerosol-generating element comprises from about 40 percent by weight to about
90 percent
by weight of polyhydric alcohol. Even more preferably, the aerosol-generating
element
comprises from about 45 percent by weight to about 90 percent by weight of
polyhydric
alcohol. In particularly preferred embodiments, the aerosol-generating element
comprises
from about 50 percent by weight to about 90 percent by weight of polyhydric
alcohol, preferably
from about 55 percent by weight to about 90 percent by weight of polyhydric
alcohol, more
preferably from about 60 percent by weight to about 90 percent by weight of
polyhydric alcohol,
even more preferably from about 65 percent by weight to about 90 percent by
weight of
polyhydric alcohol, most preferably from about 70 percent by weight to about
90 percent by
weight of polyhydric alcohol.
In further embodiments, the polyhydric alcohol content in the aerosol-
generating
formulation accounts for from about 30 percent by weight to about 85 percent
by weight based
on the total weight of the aerosol-generating element. Preferably, the
polyhydric alcohol
content in the aerosol-generating formulation accounts for from about 35
percent by weight to
about 85 percent by weight based on the total weight of the aerosol-generating
element. More
preferably, the polyhydric alcohol content in the aerosol-generating
formulation accounts for
from about 40 percent by weight to about 85 percent by weight based on the
total weight of
the aerosol-generating element. Even more preferably, the polyhydric alcohol
content in the
aerosol-generating formulation accounts for from about 45 percent by weight to
about 85
percent by weight based on the total weight of the aerosol-generating element.
In particularly
preferred embodiments, the polyhydric alcohol content in the aerosol-
generating formulation
accounts for from about 50 percent by weight to about 85 percent by weight
based on the total
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weight of the aerosol-generating element, more preferably from about 55
percent by weight to
about 85 percent by weight based on the total weight of the aerosol-generating
element, even
more preferably from about 60 percent by weight to about 85 percent by weight
based on the
total weight of the aerosol-generating element. In most preferred embodiments,
the polyhydric
alcohol content in the aerosol-generating formulation accounts for from about
65 percent by
weight to about 85 percent by weight or even from about 70 percent by weight
to about 85
percent by weight based on the total weight of the aerosol-generating element.
In these embodiments, the aerosol-generating element in accordance with the
present
invention may comprise from about 30 percent by weight to about 85 percent by
weight of a
polyhydric alcohol. Preferably, the aerosol-generating element comprises from
about 35
percent by weight to about 85 percent by weight of polyhydric alcohol. More
preferably, the
aerosol-generating element comprises from about 40 percent by weight to about
85 percent
by weight of polyhydric alcohol. Even more preferably, the aerosol-generating
element
comprises from about 45 percent by weight to about 85 percent by weight of
polyhydric
alcohol. In particularly preferred embodiments, the aerosol-generating element
comprises
from about 50 percent by weight to about 85 percent by weight of polyhydric
alcohol, preferably
from about 55 percent by weight to about 85 percent by weight of polyhydric
alcohol, more
preferably from about 60 percent by weight to about 85 percent by weight of
polyhydric alcohol,
even more preferably from about 65 percent by weight to about 85 percent by
weight of
polyhydric alcohol, most preferably from about 70 percent by weight to about
85 percent by
weight of polyhydric alcohol.
In yet further embodiments, the polyhydric alcohol content in the aerosol-
generating
formulation accounts for from about 30 percent by weight to about 80 percent
by weight based
on the total weight of the aerosol-generating element. Preferably, the
polyhydric alcohol
content in the aerosol-generating formulation accounts for from about 35
percent by weight to
about 80 percent by weight based on the total weight of the aerosol-generating
element. More
preferably, the polyhydric alcohol content in the aerosol-generating
formulation accounts for
from about 40 percent by weight to about 80 percent by weight based on the
total weight of
the aerosol-generating element. Even more preferably, the polyhydric alcohol
content in the
aerosol-generating formulation accounts for from about 45 percent by weight to
about 80
percent by weight based on the total weight of the aerosol-generating element.
In particularly
preferred embodiments, the polyhydric alcohol content in the aerosol-
generating formulation
accounts for from about 50 percent by weight to about 80 percent by weight
based on the total
weight of the aerosol-generating element, more preferably from about 55
percent by weight to
about 80 percent by weight based on the total weight of the aerosol-generating
element, even
more preferably from about 60 percent by weight to about 80 percent by weight
based on the
total weight of the aerosol-generating element. In most preferred embodiments,
the polyhydric
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alcohol content in the aerosol-generating formulation accounts for from about
65 percent by
weight to about 80 percent by weight or even from about 70 percent by weight
to about 80
percent by weight based on the total weight of the aerosol-generating element.
In such embodiments, the aerosol-generating element in accordance with the
present
invention may comprise from about 30 percent by weight to about 80 percent by
weight of a
polyhydric alcohol. Preferably, the aerosol-generating element comprises from
about 35
percent by weight to about 80 percent by weight of polyhydric alcohol. More
preferably, the
aerosol-generating element comprises from about 40 percent by weight to about
80 percent
by weight of polyhydric alcohol. Even more preferably, the aerosol-generating
element
comprises from about 45 percent by weight to about 80 percent by weight of
polyhydric
alcohol.
In particularly preferred embodiments, the polyhydric alcohol content in the
aerosol-
generating formulation accounts for from about 50 percent by weight to about
80 percent by
weight, preferably from about 55 percent by weight to about 80 percent by
weight, more
preferably from about 60 percent by weight to about 80 percent by weight, even
more
preferably from about 65 percent by weight to about 80 percent by weight, most
preferably
from about 70 percent by weight to about 80 percent by weight based on the
total weight of
the aerosol-generating element.
Preferably, the aerosol-generating formulation dispersed within the solid
continuous
matrix structure accounts for at least about 70 percent by weight of a total
weight of the
aerosol-generating element or even at least about 75 percent by weight of a
total weight of
the aerosol-generating element or at least about 80 percent by weight of a
total weight of the
aerosol-generating element.
More preferably, the aerosol-generating formulation dispersed within the solid
continuous matrix structure accounts for at least about 82 percent by weight
of a total weight
of the aerosol-generating element. Even more preferably, the aerosol-
generating formulation
dispersed within the solid continuous matrix structure accounts for at least
about 84 percent
by weight of a total weight of the aerosol-generating element.
In particularly preferred embodiments, the aerosol-generating formulation
dispersed
within the solid continuous matrix structure accounts for at least about 86
percent by weight
of a total weight of the aerosol-generating element. More preferably, the
aerosol-generating
formulation dispersed within the solid continuous matrix structure accounts
for at least about
88 percent by weight of a total weight of the aerosol-generating element Even
more
preferably, the aerosol-generating formulation dispersed within the solid
continuous matrix
structure accounts for at least about 90 percent by weight of a total weight
of the aerosol-
generating element.
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Most preferably, the aerosol-generating formulation dispersed within the solid
continuous matrix structure accounts for at least about 92 percent by weight
of a total weight
of the aerosol-generating element or at least about 93 percent by weight of a
total weight of
the aerosol-generating element or at least about 94 percent by weight of a
total weight of the
aerosol-generating element or at least about 95 percent by weight of a total
weight of the
aerosol-generating element.
In aerosol-generating elements wherein the aerosol-generating formulation
accounts for
a fraction of the overall weight of the aerosol-generating element within the
ranges described
above, it is advantageously possible to minimise the portion of heat supplied
to the aerosol-
generating element during use that is consumed for increasing the temperature
of the
encapsulation material. As such, a more efficient use of the heat supplied to
the aerosol-
generating element is made possible, such that the great majority of said heat
is effectively
employed for releasing the aerosol-formulation components from the solid
continuous matrix
structure and the generation of an aerosol.
As described briefly above, in an aerosol-generating element in accordance
with the
present invention the aerosol-generating formulation dispersed within the
solid continuous
matrix structure comprises at least one alkaloid or cannabinoid compound. In
some
embodiments, the aerosol-generating formulation dispersed within the solid
continuous matrix
structure comprises both an alkaloid compound and a cannabinoid compound.
As used herein with reference to the invention, the term "alkaloid compound"
is used
to describe any one of a class of naturally occurring organic compounds that
contain one or
more basic nitrogen atoms. Generally, an alkaloid contains at least one
nitrogen atom in an
amine-type structure. This or another nitrogen atom in the molecule of the
alkaloid compound
can be active as a base in acid-base reactions. Most alkaloid compounds have
one or more
of their nitrogen atoms as part of a cyclic system, such as for example a
heterocylic ring. In
nature, alkaloid compounds are found primarily in plants, and are especially
common in certain
families of flowering plants. However, some alkaloid compounds are found in
animal species
and fungi. In the context of the present invention, the term "alkaloid
compounds" is used to
describe both naturally derived alkaloid compounds and synthetically
manufactured alkaloid
compounds. Suitable alkaloid compounds for use in an aerosol-generating
element in
accordance with the invention include, but are not limited to, nicotine and
anatabine.
As used herein with reference to the invention, the term "cannabinoid
compound" is used
to describe any one of a class of naturally occurring compounds that are found
in parts of the
cannabis plant ¨ namely the species Cannabis saliva, Cannabis indica, and
Cannabis
ruderalis. Cannabinoid compounds are especially concentrated in the female
flower heads.
Cannabinoid compounds naturally occurring the in cannabis plant include
tetrahydrocannabinol (THC) and cannabidiol (CBD). In the context of the
present invention,
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the term "cannabinoid compounds" is used to describe both naturally derived
cannabinoid
compounds and synthetically manufactured cannabinoid compounds.
Cannabinoid compounds suitable for use in an aerosol-generating element in
accordance with the invention indude tetrahydrocannabinol (THC),
tetrahydrocannabinolic
acid (THCA), cannabidiol (CBD), cannabidiolic acid (CBDA), cannabinol (CB11),
cannabigerol
(CBG), cannabigerol monomethyl ether (CBGM), cannabivarin (CBV),
cannabidivarin (CBDV),
tetrahydrocannabivarin (THCV), cannabichromene (CBC), cannabicyclol (CBL),
cannabichromevarin (CBCV), cannabigerovarin (CBGV), cannabielsoin (CBE),
cannabicitran
(CBT).
In general, the aerosol-generating element may comprise up to about 10 percent
by
weight of an alkaloid compound or a cannabinoid compound or both. In view of
applications
of the aerosol-generating element of the invention as a substrate in an
aerosol-generating
article, this is advantageous as the content of alkaloid compound or
cannabinoid compound
or both in the element may be increased and adjusted with a view to optimising
the delivery of
alkaloid compound or cannabinoid compound or both in aerosol form to a
consumer.
Compared with existing aerosol-generating substrates based on the use of plant
material, this
may advantageously allow for higher contents of alkaloid compound or
cannabinoid
compound or both per volume of substrate (element or elements) or per weight
of substrate
(element or elements), which may be desirable from a manufacturing viewpoint.
Preferably, the content of the at least one alkaloid or cannabinoid compound
in the
aerosol-generating formulation dispersed within the solid continuous matrix
structure accounts
for at least 0.5 percent by weight of a total weight of the aerosol-generating
element. Thus,
the aerosol-generating element preferably comprises at least about 0.5 percent
by weight of
an alkaloid compound or at least 0.5 percent by weight of a cannabinoid
compound or at least
about 0.5 percent by weight of a combination of an alkaloid compound and a
cannabinoid
compound.
More preferably, the aerosol-generating element comprises at least about 1
percent by
weight of an alkaloid compound or a cannabinoid compound or both. Even more
preferably,
the aerosol-generating element comprises at least about 2 percent by weight of
an alkaloid
compound or a cannabinoid compound or both.
The aerosol-generating element preferably comprises less than about 8 percent
by
weight of an alkaloid compound or a cannabinoid compound or both. More
preferably, the
aerosol-generating element comprises less than about 6 percent by weight of an
alkaloid
compound or a cannabinoid compound or both. Even more preferably, the aerosol-
generating
element comprises less than about 5 percent by weight of an alkaloid compound
or a
cannabinoid compound or both. Most preferably, the aerosol-generating element
comprises
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less than about 4 percent by weight of an alkaloid compound or a cannabinoid
compound or
both.
In some embodiments, the aerosol-generating element comprises from about 0.5
percent by weight to about 10 percent by weight of an alkaloid compound or a
cannabinoid
compound or both, more preferably from about 1 percent by weight to about 10
percent by
weight of an alkaloid compound or a cannabinoid compound or both, even more
preferably
from about 2 percent by weight to about 10 percent by weight of an alkaloid
compound or a
cannabinoid compound or both.
In other embodiments, the aerosol-generating element comprises from about 0.5
percent by weight to about 8 percent by weight of an alkaloid compound or a
cannabinoid
compound or both, more preferably from about 1 percent by weight to about 8
percent by
weight of an alkaloid compound or a cannabinoid compound or both, even more
preferably
from about 2 percent by weight to about 8 percent by weight of an alkaloid
compound or a
cannabinoid compound or both.
In further embodiments, the aerosol-generating element comprises from about
0.5
percent by weight to about 6 percent by weight of an alkaloid compound or a
cannabinoid
compound or both, more preferably from about 1 percent by weight to about 6
percent by
weight of an alkaloid compound or a cannabinoid compound or both, even more
preferably
from about 2 percent by weight to about 6 percent by weight of an alkaloid
compound or a
cannabinoid compound or both.
In yet further embodiments, the aerosol-generating element comprises from
about 0.5
percent by weight to about 5 percent by weight of an alkaloid compound or a
cannabinoid
compound or both, more preferably from about 1 percent by weight to about 5
percent by
weight of an alkaloid compound or a cannabinoid compound or both, even more
preferably
from about 2 percent by weight to about 5 percent by weight of an alkaloid
compound or a
cannabinoid compound or both.
In particularly preferred embodiments, the aerosol-generating element
comprises from
about 0.5 percent by weight to about 4 percent by weight of an alkaloid
compound or a
cannabinoid compound or both, more preferably from about 1 percent by weight
to about 4
percent by weight of an alkaloid compound or a cannabinoid compound or both,
even more
preferably from about 2 percent by weight to about 4 percent by weight of an
alkaloid
compound or a cannabinoid compound or both.
In some embodiments, the aerosol-generating element comprises one or more of a
cannabinoid and an alkaloid compound comprising nicotine or anatabine. In some
preferred
embodiments, the aerosol-generating element comprises nicotine.
As used herein with reference to the invention, the term "nicotine" is used to
describe
nicotine, a nicotine base or a nicotine salt. In embodiments in which the
aerosol-generating
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element comprises a nicotine base or a nicotine salt, the amounts of nicotine
recited herein
are the amount of free base nicotine or amount of protonated nicotine,
respectively.
The aerosol-generating element may comprise natural nicotine or synthetic
nicotine.
The aerosol-generating element may comprise one or more monoprotic nicotine
salts.
As used herein with reference to the invention, the term "monoprotic nicotine
salt" is
used to describe a nicotine salt of a monoprotic acid.
In general, the aerosol-generating element may comprise up to about 10 percent
by
weight of nicotine. In view of applications of the aerosol-generating element
of the invention
as a substrate in an aerosol-generating article, this is advantageous as the
content of nicotine
in the element may be increased and adjusted with a view to optimising the
delivery of nicotine
in aerosol form to a consumer. Compared with existing aerosol-generating
substrates based
on the use of tobacco plant, this may advantageously allow for higher contents
of nicotine per
volume of substrate (element or elements) or per weight of substrate (element
or elements),
which may be desirable from a manufacturing viewpoint.
Preferably, the aerosol-generating element comprises at least about 0.5
percent by
weight of nicotine. More preferably, the aerosol-generating element comprises
at least about
1 percent by weight of nicotine. Even more preferably, the aerosol-generating
element
comprises at least about 2 percent by weight of nicotine.
The aerosol-generating element preferably comprises less than or equal to
about 8
percent by weight of nicotine. More preferably, the aerosol-generating element
comprises
less than or equal to about 6 percent by weight of nicotine. Even more
preferably, the aerosol-
generating element comprises less than or equal to about 5 percent by weight
of nicotine.
Most preferably, the aerosol-generating element comprises less than or equal
to about 4
percent by weight of nicotine.
In some embodiments, the aerosol-generating element comprises from about 0.5
percent by weight to about 10 percent by weight of nicotine, more preferably
from about 1
percent by weight to about 10 percent by weight of nicotine, even more
preferably from about
2 percent by weight to about 10 percent by weight of nicotine.
In other embodiments, the aerosol-generating element comprises from about 0.5
percent by weight to about 8 percent by weight of nicotine, more preferably
from about 1
percent by weight to about 8 percent by weight of nicotine, even more
preferably from about
2 percent by weight to about 8 percent by weight of nicotine.
In further embodiments, the aerosol-generating element comprises from about
0.5
percent by weight to about 6 percent by weight of nicotine, more preferably
from about 1
percent by weight to about 6 percent by weight of nicotine, even more
preferably from about
2 percent by weight to about 6 percent by weight of nicotine.
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In yet further embodiments, the aerosol-generating element comprises from
about 0.5
percent by weight to about 5 percent by weight of nicotine, more preferably
from about 1
percent by weight to about 5 percent by weight of nicotine, even more
preferably from about
2 percent by weight to about 5 percent by weight of nicotine.
In particularly preferred embodiments, the aerosol-generating element
comprises from
about 0.5 percent by weight to about 4 percent by weight of nicotine, more
preferably from
about 1 percent by weight to about 4 percent by weight of nicotine, even more
preferably from
about 2 percent by weight to about 4 percent by weight of nicotine.
Preferably, the aerosol-generating element comprises at least about 0.5
milligrams of
nicotine. More preferably, the aerosol-generating element comprises at least
about 1
milligram of nicotine. Even more preferably, the aerosol-generating element
comprises at
least about 1.5 milligrams of nicotine. In particularly preferred embodiments,
the aerosol-
generating element comprises at least about 2 milligrams of nicotine, and most
preferably at
least about 2.5 milligrams of nicotine.
The aerosol-generating element may comprise up to about 6 milligrams of
nicotine.
Preferably, the aerosol-generating element comprises less than or equal to
about 5 milligrams
of nicotine. More preferably, the aerosol-generating element comprises less
than or equal to
about 4.5 milligrams of nicotine. Even more preferably, the aerosol-generating
element
comprises less than or equal to about 4 milligrams of nicotine. In
particularly preferred
embodiments, the aerosol-generating element comprises less than or equal to
about 3.5
milligrams of nicotine, and most preferably less than or equal to about 3
milligrams of nicotine.
In some preferred embodiments, the aerosol-generating formulation dispersed
within the solid
continuous matrix structure of the aerosol-generating element comprises a
cannabinoid
compound. Preferably, the cannabinoid compound is selected from CBD and THC.
More
preferably, the cannabinoid compound is CBD.
The aerosol-generating element may comprise up to about 10 percent by weight
of CBD.
Preferably, the aerosol-generating element comprises at least about 0.5
percent by weight of
CBD. More preferably, the aerosol-generating element comprises at least about
1 percent by
weight of CBD. Even more preferably, the aerosol-generating element comprises
at least
about 2 percent by weight of CBD.
The aerosol-generating element preferably comprises less than or equal to
about 6
percent by weight of CBD. More preferably, the aerosol-generating element
comprises less
than or equal to about 5 percent by weight of CBD. Even more preferably, the
aerosol-
generating element comprises less than or equal to about 4 percent by weight
CBD.
In some embodiments, the aerosol-generating element comprises from about 0.5
percent by weight to about 10 percent by weight of CBD, more preferably from
about 1 percent
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by weight to about 10 percent by weight of CBD, even more preferably from
about 2 percent
by weight to about 10 percent by weight of CBD.
In other embodiments, the aerosol-generating element comprises from about 0.5
percent by weight to about 8 percent by weight of CBD, more preferably from
about 1 percent
by weight to about 8 percent by weight of CBD, even more preferably from about
2 percent by
weight to about 8 percent by weight of CBD.
In further embodiments, the aerosol-generating element comprises from about
0.5
percent by weight to about 6 percent by weight of CBD, more preferably from
about 1 percent
by weight to about 6 percent by weight of CBD, even more preferably from about
2 percent by
weight to about 6 percent by weight of CBD.
In yet further embodiments, the aerosol-generating element comprises from
about 0.5
percent by weight to about 5 percent by weight of CBD, more preferably from
about 1 percent
by weight to about 5 percent by weight of CBD, even more preferably from about
2 percent by
weight to about 5 percent by weight of CBD.
In particularly preferred embodiments, the aerosol-generating element
comprises from
about 0.5 percent by weight to about 4 percent by weight of CBD, more
preferably from about
1 percent by weight to about 4 percent by weight of CBD, even more preferably
from about 2
percent by weight to about 4 percent by weight of nicotine.
An aerosol-generating element in accordance with the present invention may be
a
substantially tobacco-free aerosol-generating element.
As used herein with reference to the invention, the term "substantially
tobacco-free
aerosol-generating element" describes an aerosol-generating element having a
tobacco
content of less than 1 percent by weight. For example, the aerosol-generating
element may
have a tobacco content of less than about 0.75 percent by weight, less than
about 0.5 percent
by weight or less than about 0.25 percent by weight.
The aerosol-generating element may be a tobacco-free aerosol-generating
element.
As used herein with reference to the invention, the term "tobacco-free aerosol-
generating element" describes an aerosol-generating element having a tobacco
content of 0
percent by weight
In some embodiments, the aerosol-generating element comprises tobacco material
or
a non-tobacco plant material or a plant extract By way of example, the aerosol-
generating
element may comprise tobacco particles, such as tobacco lamina particles, as
well as particles
of other botanicals, such as clove and eucalyptus.
In some embodiments, the aerosol-generating formulation dispersed within the
continuous solid matrix structure further comprises an add. More preferably,
the aerosol-
generating formulation dispersed within the continuous solid matrix structure
comprises one
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or more organic acids. Even more preferably, the aerosol-generating
formulation dispersed
within the continuous solid matrix structure comprises one or more carboxylic
acids.
Suitable carboxylic acids for use in the aerosol-generating formulation of
aerosol-
generating elements in accordance with the present invention include, but are
not limited to:
2-Ethylbutyric add, acetic acid, adipic acid, benzoic acid, butyric add,
cinnamic acid,
cycloheptane-carboxylic acid, fumaric acid, glycolic acid, hexanoic acid,
lactic acid, levulinic
add, malic add, myristic add, octanoic acid, oxalic add, propanoic acid,
pyruvic acid, succinic
acid, and undecanoic acid.
In particularly preferred embodiments, the acid is lactic acid or levulinic
add or benzoic
add or fumaric acid or acetic acid. Most preferably, the acid is lactic add.
The indusion of an add is especially preferred in embodiments of the aerosol-
generating
element wherein the aerosol-generating formulation dispersed within the
continuous solid
matrix structure comprises nicotine, as it has been observed that the presence
of an add may
stabilise dissolved species in the aerosol-generating formulation, such as
with nicotine and
other plant extracts. Without wishing to be bound by theory, it is understood
that the acid may
interact with the nicotine molecule, such that protonated nicotine is
stabilised. As protonated
nicotine is non-volatile, it is more easily found in the liquid or particulate
phase rather than in
the vapour phase of an aerosol obtained by heating the aerosol-generating
element As such,
the loss of nicotine during manufacturing of the aerosol-generating element
can be minimised,
and higher, better controlled nicotine delivery to the consumer can
advantageously be
ensured.
The aerosol-generating element may comprise up to about 10 percent by weight
of an
add.
Preferably, the aerosol-generating element comprises at least about 0.5
percent by
weight of an acid. More preferably, the aerosol-generating element comprises
at least about
1 percent by weight of an acid_ Even more preferably, the aerosol-generating
element
comprises at least about 2 percent by weight of an acid.
The aerosol-generating element preferably comprises less than or equal to
about 8
percent by weight of an acid. More preferably, the aerosol-generating element
comprises less
than or equal to about 6 percent by weight of an acid. Even more preferably,
the aerosol-
generating element comprises less than or equal to about 5 percent by weight
of an acid.
Most preferably, the aerosol-generating element comprises less than or equal
to about 4
percent by weight of an acid.
In some embodiments, the aerosol-generating element comprises from about 0.5
percent by weight to about 10 percent by weight of an acid, more preferably
from about 1
percent by weight to about 10 percent by weight of an acid, even more
preferably from about
2 percent by weight to about 10 percent by weight of an acid.
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In other embodiments, the aerosol-generating element comprises from about 0.5
percent by weight to about 8 percent by weight of an add, more preferably from
about 1
percent by weight to about 8 percent by weight of an add, even more preferably
from about 2
percent by weight to about 8 percent by weight of an acid.
In further embodiments, the aerosol-generating element comprises from about
0.5
percent by weight to about 6 percent by weight of an add, more preferably from
about 1
percent by weight to about 6 percent by weight of an add, even more preferably
from about 2
percent by weight to about 6 percent by weight of an acid.
In yet further embodiments, the aerosol-generating element comprises from
about 0.5
percent by weight to about 5 percent by weight of an add, more preferably from
about 1
percent by weight to about 5 percent by weight of an add, even more preferably
from about 2
percent by weight to about 5 percent by weight of an acid.
In particularly preferred embodiments, the aerosol-generating element
comprises from
about 0.5 percent by weight to about 4 percent by weight of an acid, more
preferably from
about 1 percent by weight to about 4 percent by weight of an acid, even more
preferably from
about 2 percent by weight to about 4 percent by weight of an acid.
Preferably, where the aerosol-generating solution comprises nicotine, the
molar ratio of
the acid to nicotine is between about 0.5:1 and about 2:1, more preferably
between about
0.75:1 and about 1.5:1, most preferably about 1:1.
Where a multivalent acid is used, such as a multivalent carboxylic acid, it
may be
preferable to provide a molar ratio of the acid groups to nicotine of between
about 0.5:1 and
about 2:11 more preferably between about 0.75:1 and about 1.5:1, most
preferably about 1:1.
The use of a multivalent add therefore enables a lower weight amount of the
acid to be used
whilst still providing the same level of protonation of the nicotine.
In preferred embodiments, the aerosol-generating element comprises at least
about 0.5
percent by weight of levulinic acid. More preferably, the aerosol-generating
element
comprises at least about 1 percent by weight of levulinic acid. Even more
preferably, the
aerosol-generating element comprises at least about 2 percent by weight of
levulinic acid.
The aerosol-generating element preferably comprises less than or equal to
about 8
percent by weight of levulinic add. More preferably, the aerosol-generating
element
comprises less than or equal to about 6 percent by weight of levulinic add.
Even more
preferably, the aerosol-generating element comprises less than or equal to
about 5 percent
by weight of levulinic acid. Most preferably, the aerosol-generating element
comprises less
than or equal to about 4 percent by weight of levulinic add.
In some embodiments, the aerosol-generating element comprises from about 0.5
percent by weight to about 10 percent by weight of levulinic add, more
preferably from about
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1 percent by weight to about 10 percent by weight of levulinic acid, even more
preferably from
about 2 percent by weight to about 10 percent by weight of levulinic acid.
In other embodiments, the aerosol-generating element comprises from about 0.5
percent by weight to about 8 percent by weight of levulinic add, more
preferably from about 1
percent by weight to about 8 percent by weight of levulinic acid, even more
preferably from
about 2 percent by weight to about 8 percent by weight of levulinic acid.
In further embodiments, the aerosol-generating element comprises from about
0.5
percent by weight to about 6 percent by weight of levulinic acid, more
preferably from about 1
percent by weight to about 6 percent by weight of levulinic acid, even more
preferably from
about 2 percent by weight to about 6 percent by weight of levulinic acid.
In yet further embodiments, the aerosol-generating element comprises from
about 0.5
percent by weight to about 5 percent by weight of levulinic add, more
preferably from about 1
percent by weight to about 5 percent by weight of levulinic acid, even more
preferably from
about 2 percent by weight to about 5 percent by weight of levulinic acid.
In particularly preferred embodiments, the aerosol-generating element
comprises from
about 0.5 percent by weight to about 4 percent by weight of levulinic add,
more preferably
from about 1 percent by weight to about 4 percent by weight of levulinic acid,
even more
preferably from about 2 percent by weight to about 4 percent by weight of
levulinic add.
In other preferred embodiments, the aerosol-generating element comprises at
least
about 0.5 percent by weight of lactic add. More preferably, the aerosol-
generating element
comprises at least about 1 percent by weight of lactic acid. Even more
preferably, the aerosol-
generating element comprises at least about 2 percent by weight of lactic add.
The aerosol-generating element preferably comprises less than or equal to
about 8
percent by weight of lactic acid. More preferably, the aerosol-generating
element comprises
less than or equal to about 6 percent by weight of lactic acid. Even more
preferably, the
aerosol-generating element comprises less than or equal to about 5 percent by
weight of lactic
add. Most preferably, the aerosol-generating element comprises less than or
equal to about
4 percent by weight of lactic acid.
In some embodiments, the aerosol-generating element comprises from about 0.5
percent by weight to about 10 percent by weight of lactic acid, more
preferably from about 1
percent by weight to about 10 percent by weight of lactic acid, even more
preferably from
about 2 percent by weight to about 10 percent by weight of lactic add.
In other embodiments, the aerosol-generating element comprises from about 0.5
percent by weight to about 8 percent by weight of lactic acid, more preferably
from about 1
percent by weight to about 8 percent by weight of lactic acid, even more
preferably from about
2 percent by weight to about 8 percent by weight of lactic acid.
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In further embodiments, the aerosol-generating element comprises from about
0.5
percent by weight to about 6 percent by weight of lactic acid, more preferably
from about 1
percent by weight to about 6 percent by weight of lactic acid, even more
preferably from about
2 percent by weight to about 6 percent by weight of lactic acid.
In yet further embodiments, the aerosol-generating element comprises from
about 0.5
percent by weight to about 5 percent by weight of lactic acid, more preferably
from about 1
percent by weight to about 5 percent by weight of lactic acid, even more
preferably from about
2 percent by weight to about 5 percent by weight of lactic acid.
In particularly preferred embodiments, the aerosol-generating element
comprises from
about 0.5 percent by weight to about 4 percent by weight of lactic acid, more
preferably from
about 1 percent by weight to about 4 percent by weight of lactic acid, even
more preferably
from about 2 percent by weight to about 4 percent by weight of lactic add.
An aerosol-generating element according to the present invention preferably
comprises
less than or equal to about 25 percent by weight of water.
More preferably, the aerosol-generating element comprises less than or equal
to about
20 percent by weight of water. Even more preferably, the aerosol-generating
element
comprises less than or equal to about 15 percent of water.
An aerosol-generating element according to the present invention preferably
comprises
at least about 2.5 percent by weight of water. More preferably, the aerosol-
generating element
according to the present invention preferably comprises at least about 5
percent by weight of
water. Even more preferably, the aerosol-generating element according to the
present
invention preferably comprises at least about 7.5 percent by weight of water.
Most preferably,
the aerosol-generating element according to the present invention preferably
comprises at
least about 10 percent by weight of water.
In general, it has been observed that the presence of some water contributes
to
imparting desirable stability to the aerosol-generating element At the same
time, a residual
content of water of 25 percent by weight or less is desirable as an aerosol-
generating element
may be obtained that is substantially not sticky. Further, when heating an
aerosol-generating
element with a lower water content, an aerosol more concentrated in the
polyhydric alcohol
and in the alkaloid or cannabinoid compound, such as nicotine, may be provided
to the
consumer.
In some embodiments, the aerosol-generating element according to the present
invention comprises from about 2_5 percent by weight to about 25 percent by
weight of water.
Preferably, the aerosol-generating element according to the present invention
comprises from
about 5 percent by weight to about 25 percent by weight of water. More
preferably, the
aerosol-generating element according to the present invention comprises from
about 7.5
percent by weight to about 25 percent by weight of water. Most preferably, the
aerosol-
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generating element according to the present invention comprises from about 10
percent by
weight to about 25 percent by weight of water.
In other embodiments, the aerosol-generating element according to the present
invention comprises from about 2.5 percent by weight to about 20 percent by
weight of water.
Preferably, the aerosol-generating element according to the present invention
comprises from
about 5 percent by weight to about 20 percent by weight of water. More
preferably, the
aerosol-generating element according to the present invention comprises from
about 7.5
percent by weight to about 20 percent by weight of water. Most preferably, the
aerosol-
generating element according to the present invention comprises from about 10
percent by
weight to about 20 percent by weight of water.
In further embodiments, the aerosol-generating element according to the
present
invention comprises from about 2.5 percent by weight to about 15 percent by
weight of water.
Preferably, the aerosol-generating element according to the present invention
comprises from
about 5 percent by weight to about 15 percent by weight of water. More
preferably, the
aerosol-generating element according to the present invention comprises from
about 7.5
percent by weight to about 15 percent by weight of water. Most preferably, the
aerosol-
generating element according to the present invention comprises from about 10
percent by
weight to about 15 percent by weight of water.
In yet further embodiments, the aerosol-generating element according to the
present
invention comprises from about 2.5 percent by weight to about 10 percent by
weight of water.
Preferably, the aerosol-generating element according to the present invention
comprises from
about 5 percent by weight to about 10 percent by weight of water. More
preferably, the
aerosol-generating element according to the present invention comprises from
about 7.5
percent by weight to about 10 percent by weight of water. Most preferably, the
aerosol-
generating element according to the present invention comprises from about 10
percent by
weight to about 10 percent by weight of water.
An aerosol-generating element according to the present invention preferably
has a water
activity of less than or equal to about 0.7.
The term "water activity" is used herein with reference to the present
invention to denote
the ratio of the partial water vapour pressure in equilibrium with an aerosol-
generating element
to the water-vapour saturation pressure in equilibrium with pure water at the
same
temperature. As such, water activity is a dimensionless quantity between 0,
which
corresponds to a completely anhydrous substance, and 1, which corresponds to
pure salt-free
water. Methods of measuring the water activity of an aerosol-generating
element in
accordance with the present invention are described in the 2017 publication of
ISO 18787
(Foodstuffs ¨ Determination of water activity ¨ dew point measurement).
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An aerosol-generating element in accordance with the present invention may
optionally
further comprise a flavourant. The flavourant may be in liquid form, or solid
form. Optionally,
the flavourant may be provided in a microencapsulated form wherein the
flavourant is released
upon heating.
Preferably, the aerosol-generating element comprises at least about 0.05
percent by
weight of flavourant, more preferably at least about 0.1 percent by weight of
flavourant based
on the total weight of the aerosol-generating element. The aerosol-generating
element
preferably comprises less than or equal to about 1 percent by weight of
flavourant, more
preferably less than or equal to about 0.5 percent by weight of flavourant
based on the total
weight of the aerosol-generating element.
In some embodiments, the aerosol-generating element comprises from about 0.05
percent by weight to about 1 percent by weight of flavourant, preferably from
about 0.05
percent by weight to about 0.5 percent by weight of flavourant based on the
total weight of the
aerosol-generating element In other embodiments, the aerosol-generating
element
comprises from about 0.1 percent by weight to about 1 percent by weight of
flavourant,
preferably from about OA percent by weight to about 0.5 percent by weight of
flavourant based
on the total weight of the aerosol-generating element
Suitable flavourants for use in an aerosol-generating element in accordance
with the
present invention include, but are not limited to: tobacco, menthol, mint such
as peppermint
or spearmint, cocoa, liquorice, fruit (such as citrus), gamma octalactone,
vanillin, spices (such
as cinnamon), methyl salicylate, linalool, eugenol, eucalyptol, bergamot oil,
eugenol oil,
geranium oil, lemon oil, ginger oil, and tobacco flavour.
An aerosol-generating element in accordance with the present invention may
optionally
further comprise a plurality of susceptor particles. Susceptor particles are
conductive particles
that have the ability to convert electromagnetic energy and convert it to
heat. When located
in an alternating electromagnetic field, eddy currents are induced and
hysteresis losses occur
in the susceptor particles causing heating of the susceptor. As the susceptor
particles are
located in thermal contact or close thermal proximity with the aerosol-
generating formulation
of the aerosol-generating element, the aerosol-generating formulation is
heated by the
susceptor particles such that an aerosol is formed.
The inclusion of susceptor particles in the aerosol-generating solution
therefore provides
an aerosol-generating element that is inductively heatable. When the aerosol-
generating
element is used in a device comprising an induction heater, changing
electromagnetic fields
generated by one or several induction coils of an inductive heating device
heats the susceptor
particles, which then transfer the heat to the surrounding aerosol-generating
formulation of the
aerosol-generating element, mainly by conduction of heat.
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The susceptor particles may be formed from any material that can be
inductively heated
to a temperature sufficient to generate an aerosol from the aerosol-generating
formulation.
Preferred susceptor particles comprise a metal or carbon. Preferred susceptor
particles may
comprise or consist of a ferromagnetic material, for example a ferromagnetic
alloy, terrific iron,
or a ferromagnetic steel or stainless steel. Suitable susceptor particles may
be, or comprise,
aluminium. Preferred susceptor particles may be heated to a temperature in
excess of 250
degrees Celsius. Suitable susceptor particles may comprise a non-metallic core
with a metal
layer disposed on the non-metallic core, for example metallic tracks formed on
a surface of a
ceramic core. Susceptor particles may have a protective external layer, for
example a
protective ceramic layer or protective glass layer encapsulating the susceptor
particle. The
susceptor particles may comprise a protective coating formed by a glass, a
ceramic, or an
inert metal, formed over a core of susceptor material.
The susceptor particles may have an average particle size up to about 60
micrometres.
For example, the susceptor particles may have an average particle size of less
than or equal
to about 50 micrometres, or less than or equal to about 40 micrometres or less
than or equal
to about 35 micrometres.
Typically, in an aerosol-generating solution for use in methods in accordance
with the
present invention the susceptor particles have an average particle size of at
least about 1
micrometre, or at least about 2 micrometres, or at least about 5 micrometres
or at least about
micrometres.
For example, the susceptor particles in the aerosol-generating solution may
have an
average particle size from about 1 micrometre to about 60 micrometres, or from
about 2
millimetres to about 50 micrometres, or from about 5 micrometres to about 40
micrometres,
or from about 10 micrometres to about 35 micrometres.
Optionally, the aerosol-generating formulation dispersed within the solid
continuous
matrix structure of aerosol-generating elements in accordance with the present
invention may
further comprise a solid filler. The inclusion of a solid filler may
advantageously improve the
physical properties of the aerosol-generating element. VVithout wishing to be
bound by theory,
it is understood that, during manufacture of the aerosol-generating element,
inclusion of a
solid filler may facilitate control of the properties of the aerosol-
generating solution during the
step of forming a discrete portion of the aerosol-generating solution.
Suitable solid fillers would
be known to the skilled person.
For example, an aerosol-generating element in accordance with the present
invention
may optionally further comprise particles of plant material obtained by
pulverising, grinding or
comminuting plant material. By way of example, the aerosol-generating element
may further
comprise tea particles, coffee particles, cannabis particles, clove particles,
eucalyptus
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particles, star anise particles, ginger particles. Additionally or
alternatively, an aerosol-
generating element in accordance with the present invention may optionally
further comprise
particles obtained by pulverising, grinding or comminuting one or more of
tobacco leaf lamina
and tobacco leaf stems. The inventors of the present invention have found that
through the
incorporation of such plant particles into the aerosol-generating element it
is advantageously
possible to produce an aerosol with provides a novel sensory experience. Such
an aerosol
provides unique flavours and may provide an increased level of mouthfullness.
In embodiments wherein the aerosol-generating element comprises plant
particles, the
amount of the plant particles in the aerosol-generating solution is adjusted
in order to provide
the desired level of the plant particles within the aerosol-generating element
and the desired
level of flavour within the generated aerosol. The aerosol-generating element
may comprise
up to about 40 percent by weight of plant particles. Preferably, the aerosol-
generating element
comprises less than or equal to about 35 percent by weight of plant particles.
More preferably,
the aerosol-generating element comprises less than or equal to about 30
percent by weight of
plant particles. Even more preferably, the aerosol-generating element
comprises less than or
equal to about 25 percent by weight of plant particles.
In some embodiments, the aerosol-generating element comprises at least about 1
percent by weight of plant particles. Preferably, the aerosol-generating
element comprises at
least about 2 percent by weight of plant particles. More preferably, the
aerosol-generating
element comprises at least about 5 percent by weight of plant particles. Even
more preferably,
the aerosol-generating element comprises at least about 10 percent by weight
of plant
particles.
In some preferred embodiments, the aerosol-generating element comprises from
about
1 percent by weight to about 40 percent by weight of plant particles.
Preferably, the aerosol-
generating element comprises from about 2 percent by weight to about 40
percent by weight
of plant particles. More preferably, the aerosol-generating element comprises
from about 5
percent by weight to about 40 percent by weight of plant particles. Even more
preferably, the
aerosol-generating element comprises from about 10 percent by weight to about
40 percent
by weight of plant particles.
In other embodiments, the aerosol-generating element comprises from about 1
percent
by weight to about 35 percent by weight of plant particles. Preferably, the
aerosol-generating
element comprises from about 2 percent by weight to about 35 percent by weight
of plant
particles. More preferably, the aerosol-generating element comprises from
about 5 percent
by weight to about 35 percent by weight of plant particles. Even more
preferably, the aerosol-
generating element comprises from about 10 percent by weight to about 35
percent by weight
of plant particles.
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In further embodiments, the aerosol-generating element comprises from about 1
percent
by weight to about 30 percent by weight of plant particles. Preferably, the
aerosol-generating
element comprises from about 2 percent by weight to about 30 percent by weight
of plant
particles. More preferably, the aerosol-generating element comprises from
about 5 percent
by weight to about 30 percent by weight of plant particles. Even more
preferably, the aerosol-
generating element comprises from about 10 percent by weight to about 30
percent by weight
of plant particles.
In yet further embodiments, the aerosol-generating element comprises from
about 1
percent by weight to about 25 percent by weight of plant particles.
Preferably, the aerosol-
generating element comprises from about 2 percent by weight to about 25
percent by weight
of plant particles. More preferably, the aerosol-generating element comprises
from about 5
percent by weight to about 25 percent by weight of plant particles. Even more
preferably, the
aerosol-generating element comprises from about 10 percent by weight to about
25 percent
by weight of plant particles.
The provision of an amount of plant particles within this range ensures that
sufficient
flavour can be achieved from the plant particles but without affecting the
consistency of the
aerosol-generating solution so much that processing of the aerosol-generating
solution to form
the aerosol-generating element is adversely affected.
In embodiments wherein the aerosol-generating element comprises plant
particles, the
plant particles may have an average particle size up to about 60 micrometres.
Preferably, in
an aerosol-generating element in accordance with the present invention the
plant particles
have an average particle size of less than or equal to about 50 micrometres.
More preferably,
in an aerosol-generating element in accordance with the present invention the
plant particles
have an average particle size of less than or equal to about 40 micrometres.
Even more
preferably, in an aerosol-generating element in accordance with the present
invention the plant
particles have an average particle size of less than or equal to about 30
micrometres.
Typically, in an aerosol-generating element in accordance with the present
invention the
plant particles have an average particle size of at least about 1 micrometre.
Preferably, in an
aerosol-generating element in accordance with the present invention the plant
particles have
an average particle size of at least about 2 micrometres. More preferably, in
an aerosol-
generating element in accordance with the present invention the plant
particles have an
average particle size of at least about 5 micrometres. Even more preferably,
in an aerosol-
generating element in accordance with the present invention the plant
particles have an
average particle size of at least about 10 micrometres.
In some preferred embodiments, in an aerosol-generating element in accordance
with
the present invention the plant particles have an average particle size from
about 1 millimetre
to about 60 micrometres. Preferably, in an aerosol-generating element in
accordance with the
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present invention the plant particles have an average particle size from about
2 millimetres to
about 60 micrometres. More preferably, in an aerosol-generating element in
accordance with
the present invention the plant particles have an average particle size from
about 5 millimetres
to about 60 micrometres. Even more preferably, in an aerosol-generating
element in
accordance with the present invention the plant particles have an average
particle size from
about 10 millimetres to about 60 micrometres.
In other embodiments, in an aerosol-generating element in accordance with the
present
invention the plant particles have an average particle size from about 1
millimetre to about 50
micrometres. Preferably, in an aerosol-generating element in accordance with
the present
invention the plant particles have an average particle size from about 2
millimetres to about
50 micrometres. More preferably, in an aerosol-generating element in
accordance with the
present invention the plant particles have an average particle size from about
5 millimetres to
about 50 micrometres. Even more preferably, in an aerosol-generating element
in accordance
with the present invention the plant particles have an average particle size
from about 10
millimetres to about 50 micrometres.
In further embodiments, in an aerosol-generating element in accordance with
the
present invention the plant particles have an average particle size from about
1 millimetre to
about 40 micrometres. Preferably, in an aerosol-generating element in
accordance with the
present invention the plant particles have an average particle size from about
2 millimetres to
about 40 micrometres. More preferably, in an aerosol-generating element in
accordance with
the present invention the plant particles have an average particle size from
about 5 millimetres
to about 40 micrometres. Even more preferably, in an aerosol-generating
element in
accordance with the present invention the plant particles have an average
particle size from
about 10 millimetres to about 40 micrometres.
In yet further embodiments, in an aerosol-generating element in accordance
with the
present invention the plant particles have an average particle size from about
1 millimetre to
about 30 micrometres. Preferably, in an aerosol-generating element in
accordance with the
present invention the plant particles have an average particle size from about
2 millimetres to
about 30 micrometres. More preferably, in an aerosol-generating element in
accordance with
the present invention the plant particles have an average particle size from
about 5 millimetres
to about 30 micrometres. Even more preferably, in an aerosol-generating
element in
accordance with the present invention the plant particles have an average
particle size from
about 10 millimetres to about 30 micrometres. n aerosol-generating element in
accordance
with the invention may have an equivalent diameter of at least about 0.5
millimetres.
The term "equivalent diameter of an aerosol-generating element' is used herein
to
denote the diameter of the sphere which has the same volume as the aerosol-
generating
element In general, the aerosol-generating element may have any shape,
although a
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spherical or quasi-spherical shape, such as an egg shape or ellipsoid shape is
preferred_ For
an aerosol-generating element having a spherical shape and a circular
transverse cross-
section, the equivalent diameter is the diameter of the cross-section of the
aerosol-generating
element.
Preferably, the aerosol-generating element has an equivalent diameter of at
least about
1 millimetre. More preferably, the aerosol-generating element has an
equivalent diameter of
at least about 2 millimetres. Even more preferably, the aerosol-generating
element has an
equivalent diameter of at least about 3 millimetres.
An aerosol-generating element in accordance with the invention preferably has
an
equivalent diameter of less than or equal to about 8 millimetres. More
preferably, the aerosol-
generating element has an equivalent diameter of less than or equal to about 6
millimetres.
Even more preferably, the aerosol-generating element has an equivalent
diameter of less than
or equal to about 5 millimetres.
In some embodiments, the aerosol-generating element has an equivalent diameter
from
about 0.5 millimetres to about 8 millimetres, preferably from about 1
millimetre to about 8
millimetres, more preferably from about 2 millimetres to about 8 millimetres,
even more
preferably from about 3 millimetres to about 8 millimetres.
In other embodiments, the aerosol-generating element has an equivalent
diameter from
about 0.5 millimetres to about 6 millimetres, preferably from about 1
millimetre to about 6
millimetres, more preferably from about 2 millimetres to about 6 millimetres,
even more
preferably from about 3 millimetres to about 6 millimetres.
In further embodiments, the aerosol-generating element has an equivalent
diameter
from about 0.5 millimetres to about 5 millimetres, preferably from about 1
millimetre to about
millimetres, more preferably from about 2 millimetres to about 5 millimetres,
even more
preferably from about 3 millimetres to about 5 millimetres.
In particularly preferred embodiments, the aerosol-generating element has an
equivalent diameter of about 4 millimetres or about 4.5 millimetres.
Aerosol-generating elements in accordance with the present invention may have
an
ovality up to about 35 percent
The term "ovality" as used herein with reference to the present invention
denotes the
degree of deviation from a perfect circle. Ovality is expressed as a
percentage and the
mathematical definition is given below.
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ab
Circular
alb
Oval shape
141, shape
a = b
VW a#b
2(ct ¨ b)
ovality (%) ¨
_________________________________________________________________ x 100%
a + b
To determine the ovality of an object, such as an aerosol-generating element,
the object
can be viewed along a direction substantially perpendicular to a cross-section
of the aeroso-
generating element. By way of example, the aerosol-generating element can be
positioned
on a transparent stage so that an image of the aerosol-generating element is
recorded by a
suitable imaging device located below the stage. Dimension "a" is taken to be
the largest
external diameter of the image of the aerosol-generating element, and
dimension "b" is taken
to be the smallest external diameter of the image of the aerosol-generating
element. The
process is repeated for a total of ten aerosol-generating elements having the
same
composition and prepared by means of the same process and under the same
operating
conditions. The number average of the ten ovality measurements is recorded as
the ovality
for that aerosol-generating element.
Preferably, an aerosol-generating element in accordance with the invention has
an
ovality of less than or equal to about 30 percent. More preferably, an aerosol-
generating
element in accordance with the invention has an ovality of less than or equal
to about 25
percent. Even more preferably, an aerosol-generating element in accordance
with the
invention has an ovality of less than or equal to about 20 percent
An aerosol-generating element in accordance with the invention typically has
an ovality
of at least about 1 percent. Preferably, the aerosol-generating element has an
ovality of at
least 2 percent. More preferably, the aerosol-generating element has an
ovality of at least 3
percent. Even more preferably, the aerosol-generating element has an ovality
of at least 4
percent
In some embodiments, the aerosol-generating element has an ovality from about
1
percent to about 30 percent, more preferably from about 2 percent to about 30
percent, more
preferably from about 3 percent to about 30 percent, even more preferably from
about 4
percent to about 30 percent.
In other embodiments, the aerosol-generating element has an ovality from about
1
percent to about 25 percent, more preferably from about 2 percent to about 25
percent, more
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preferably from about 3 percent to about 25 percent, even more preferably from
about 4
percent to about 25 percent.
In further embodiments, the aerosol-generating element has an ovality from
about 1
percent to about 20 percent, more preferably from about 2 percent to about 30
percent, more
preferably from about 3 percent to about 20 percent, even more preferably from
about 4
percent to about 20 percent
An aerosol-generating article in accordance with the present invention may
have an
exposed surface area to volume ratio up to 25 cm-1.
The expression "exposed surface area to volume ratio" as used herein with
reference to
the present invention denotes the ratio between the overall outer surface area
of the aerosol-
generating element, that is exposed and available for heat and mass exchange,
and the
overall volume of the aerosol-generating element.
As the aerosol-generating elements in accordance with the invention have low
ovality
and may be assimilated to spherical objects, the volume of an aerosol-
generating element in
accordance with the invention can be expressed by the formula
4n- - (Req)3
volume ¨
__________________________________________________________________________
3
The exposed surface area of an aerosol-generating element in accordance with
the
invention can be estimated by the formula
exposed surface area = 47r - (Req)2
Dimension Reg denotes an equivalent radius of the aerosol-generating element.
Preferably, the aerosol-generating article has an exposed surface area to
volume ratio
of at least about 0.083 cm* More preferably, the aerosol-generating article
has an exposed
surface area to volume ratio of at least about 0.166 cm-1. Even more
preferably, the aerosol-
generating article has an exposed surface area to volume ratio of at least
about 0.249 cm-1.
The aerosol-generating article preferably has an exposed surface area to
volume ratio
of less than or equal to about 24 cm-1. More preferably, the aerosol-
generating article has an
exposed surface area to volume ratio of less than or equal to about 20 crn-1.
Even more
preferably, the aerosol-generating article has an exposed surface area to
volume ratio of less
than or equal to about 16 cm-1.
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In some embodiment, the aerosol-generating article has an exposed surface area
to
volume ratio from about 0.083 cm-1 to about 24 cm-1, more preferably from
about 0.166 cm-1
to about 24 cm-1, even more preferably from about 0.249 cm-1 to about 24 cm4
.
In other embodiments, the aerosol-generating article has an exposed surface
area to
volume ratio from about 0.083 cm-1 to about 20 cm-1, more preferably from
about 0.166 cm-1
to about 20 cm-1, even more preferably from about 0.249 cm-1 to about 20 cm-1.
In further embodiments, the aerosol-generating article has an exposed surface
area to
volume ratio from about 0.083 cm-1 to about 16 cm-1, more preferably from
about 0.166 cm-1
to about 16 cm-1, even more preferably from about 0.249 cm-1 to about 16 cm-1.
In some embodiments, aerosol-generating elements in accordance with the
present
invention may be coated. In practice, an outer coating layer may optionally be
provided on
the aerosol-generating elements as described above. This may be achieved by
means of a
coating step that may take place before the drying step or after the drying
step. An optional
drying step may be incorporated after the coating step.
The provision of a coating layer on the aerosol-generating element may be
desirable for
many different reasons. For example, a coating layer may advantageously limit
the
permeation of oxygen or water vapour into the aerosol-generating element,
which may help to
extend the shelf life of the aerosol-generating element. Alternatively or in
addition, a coating
layer may help to protect the structural integrity of the aerosol-generating
element or to
provide improved smoothness of the aerosol-generating element In certain
embodiments, a
relatively brittle coating layer may be added to the aerosol-generating
element that is adapted
to be broken by the consumer prior to use. This type of coating layer can
therefore provide
the consumer with a tactile and audible indication that the aerosol-generating
element has
been activated. Alternatively or in addition, the provision of a coating layer
on the aerosol-
generating element may be used to adjust the colour of the aerosol-generating
element, for
example, to provide a visual indication of a property of the aerosol-
generating element, such
as the flavour or the content of nicotine.
Suitable types of coating material would be known to the skilled person. For
example,
a coating layer of a water soluble film former, such as HPMC or shellac, may
be applied to the
aerosol-generating element. Such film formers will adhere strongly to the
surface of the
aerosol-generating element. In a further example, a coating layer of sodium
alginate may be
added, which will cross-link with any remaining calcium ions on the surface of
the aerosol-
generating element to form a thin film of calcium alginate.
A coating layer may be applied to the outer surface of the aerosol-generating
element
using a variety of coating techniques. Suitable apparatus and techniques would
be known to
the skilled person.
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Aerosol-generating elements as described above may find use as aerosol-
generating
substrate for aerosol-generating articles of the type wherein the substrate is
heated to release
an inhalable aerosol ¨ as opposed to articles wherein a substrate is burned to
produce a
smoke.
Because aerosol-generating elements in accordance with the invention are easy
to
manufacture and predetermined, discrete amounts of an aerosol-generating
formulation may
thus be provided in encapsulated form, and because the composition of the
aerosol-
generating formulation ¨ especially as regards the content of polyhydric
alcohol and of the
alkaloid or cannabinoid compound ¨ can be finely tuned and controlled, aerosol-
generating
elements in accordance with the invention are versatile and can be used as
substrates in a
number of arrangement&
By way of example, a plurality of aerosol-generating elements in accordance
with the
invention may be provided within a cavity defined by a tubular element, such
that the outer
surface of the aerosol-generating elements is exposed inside the longitudinal
airflow channel
defined by the cavity. Upon heating, an aerosol can be generated from the
aerosol-generating
elements, which is thus released into the airflow channel and can be drawn
through the tubular
element into the consumer's mouth.
Aerosol-generating elements as described above may thus find use in an aerosol-
generating system comprising one or more aerosol-generating elements or an
aerosol-
generating article as described above and an electrically operated aerosol-
generating device.
A suitable aerosol-generating device comprises a heating element and a heating
chamber
configured to receive the one or more aerosol-generating elements or the
article so that the
one or more aerosol-generating element elements are heated in the heating
chamber by the
heating element.
Upon heating, aerosol-generating elements in accordance with the present
invention
release an aerosol containing the aerosol-generating formulation components,
including in
particular the polyhydric alcohol and the alkaloid or cannabinoid compound.
When an aerosol-
generating element in accordance with the present invention is heated to a
temperature in the
range from about 150 degrees Celsius to about 350 degrees Celsius, the aerosol-
generating
element has been found to lose weight without undergoing a significant volume
contraction.
Further, it has been found that, when an aerosol-generating element in
accordance with the
present invention is heated to a temperature in the range from about 150
degrees Celsius to
about 350 degrees Celsius, and heat is supplied until no additional weight
loss is detected, a
residual weight of the aerosol-generating element is typically less than 120
percent of a weight
of the solid continuous matrix structure components, preferably less than 115
percent of a
weight of the solid continuous matrix structure components, more preferably
less than 115
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percent of a weight of the solid continuous matrix structure components, even
more preferably
less than 105 percent of a weight of the solid continuous matrix structure
components.
Most preferably, when an aerosol-generating element in accordance with the
present
invention is heated to a temperature in the range from about 150 degrees
Celsius to about
350 degrees Celsius, and heat is supplied until no additional weight loss is
detected, a residual
weight of the aerosol-generating element substantially corresponds to the
total weight of the
components of the solid continuous matrix structure.
An embodiment of the invention will now be further described, by way of
example only.
Example
An aerosol-generating solution is formed from a mixture of the following
components:
Component % by
weight
Glycerin
43.6
Sodium alginate
2.1
Nicotine
1.2
Levulinic acid
1.4
Water
51.7
In an initial step, the sodium alginate is added to the water to form a matrix
polymer
solution. The nicotine is then added, followed by the glycerin and finally the
levulinic acid.
The resultant aerosol-generating solution is extruded through a 5 millimetre
nozzle to
form a plurality of droplets, which are then dropped from a height of 30
centimetres into a
cross-linking solution having the following composition, at room temperature:
Component % by
weight
Glycerin
42.9
Water
52.1
Calcium chloride
5.0
The droplets are left in the cross-linking solution for a period of 25 minutes
before being
removed and dried at 25 degrees Celsius for 12 hours, in a tray dryer. The
resultant dried
aerosol-generating elements are in the form of solid, spherical beads having a
diameter of
about 4.6 mm. Each bead has a weight of approximately 65 mg, a water activity
of 0.4 and
the following composition:
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Component % by
weight
Glycerin 76.8
Alginate 3.8
Nicotine 2.4
Levulinic acid 2.1
Water 14.4
Calcium chloride 0.5
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