Note: Descriptions are shown in the official language in which they were submitted.
,W0 95/16436 ~ ~ ~ ~ PCT/US94/12158
-1-
LIPID VESICLES CONTAINING AVOCADO OIL UNSAPONIFIABLES
The present invention relates to formulations for lipid vesicles and methods
of their
manufacture. More particularly, the present invention discloses paucimellar
lipid vesicles
designed of materials which have exceptional properties for cosmetic, edible,
dermatological,
and pharmaceutical use. The paucimellar vesicles have 2-10 lipid bilayers
surrounding a
large, amorphous central cavity which contains a water-immiscible oily
material including
triglycerides supplied by avocado oil unsaponifiables. The lipid bilayers of
these vesicles
contain at least one non-phospholipid amphiphile as the primary structural
material of the
lipid bilayers, along with phytosterol from avocado oil unsaponifiables which
acts as a
membrane or bilayer modulator.
Lipid vesicles are substantially spherical structures made of amphiphiles,
e.g.,
surfactants or phospholipids. The lipids of these spherical vesicles are
generally organized in
the form of lipid bilayers, e.g., multiple onion-like shells of lipid bilayers
which encompass
an aqueous volume between the bilayers. Paucilamellar lipid vesicles have 2-10
peripheral
bilayers which surround a large, unstructured central cavity.
Until recently, liposome technology has been concerned mostly with vesicles
composed of phospholipids. This is primarily because phospholipids are the
principal
structural components of natural membranes and, accordingly, lipid vesicles
have been used
as a model system for studying natural membranes. However, there are a number
of
problems associated with using phospholipids as synthetic membranes.
Biological
membranes are stabilized by membrane proteins and maintained by extensive
enzymatic
"support" systems that rapidly tum over, exchange or modify membrane lipids.
Neither
membrane proteins nor the requisite enzymatic support systems can be
practically
incorporated into the wall structure of liposomes, making the structures
inherently less stable
than natural membranes. In addition, the biological environment contains
several potent
phospholipases that rapidly break down free phospholipids. These phospholipids
will attack
liposomes and degrade the membrane. For these reasons, phospholipid liposomes
placed in
an in vivo environment are rapidly degraded.
Moreover, phospholipid liposome technology has other problems. Phospholipids
are
labile and expensive to purify or synthesize. In addition, classic
phospholipid liposomes are
in the form of multilamellar as opposed to paucilamellar vesicles and have
poor carrying
capacities, especially for lipophilic materials, and have poor shelf lives
unless lyophilized in
the dark with antioxidants. While unilamellar vesicles (these only having one
bilayer) add
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additional carrying capacity. they are much less stable. Finally,
phospholipids degrade too
rapidly in_ viv for most pharmaceutical or vaccine applications.
. For these reasons, there is increasing interest in liposomes made of
commercially
available nonphospholipid amphiphiles (see, e.g., U.S. Pat. No. 4,217,344, U.S
Pat. No.
4,917,951, and U.S. Pat. No. 4,911,928). These molecules have a hydrophilic
"head" group
attached to a hydrophobic "tail" and are derived from long chain fatty acids,
long chain
alcohols and their derivatives, long chain amines, and polyol sphingo- and
glycerolipids.
Commercially available amphiphile surfactants include, for example, the BRIJ~
family of
polyoxyethylene fatty ethers, the SPAN sorbitan fatty acid esters, the
TWEEN'ethoxylated
sorbitan fatty acid esters, glyceryl monostearate, glyceryl distearate, and
glyceryl dilaurate,
all available from ICI Americas, Inc. of Wilmington, De.
Paucilamellar vesicles comprised of such non-phospholipid amphiphiles provide
a
number of advantages over classical phospholipid multilamellar liposomes. For
instance.
these vesicles have a high carrying capacity for water-soluble and water
immiscible
substances. Also, the amphiphiles used to make up the vesicle bilayers can
often be used as
emulsifiers or thickeners, providing the "feel" to certain cosmetics and/or
dermatologicals.
Furthermore, many of these amphiphiles fall under the GRAS list of edible
materials and
therefore can be used in many food and pharmaceutical products.
It has previously been shown that when forming lipid vesicles containing at
least one
amphiphile as the primary lipid of the bilayers, the addition of a membrane
modulator
considerably improves the shape and size of lipid vesicles, as well as the
consistency of the
formulation after processing (See e.g., U.S. Patent No. 5,260,065). In the
past, cholesterol
has generally been used for this purpose. Sterols such as cholesterol also act
to modify the
thermotropic phase transition of the amphiphiles. However, cholesterol has the
drawback of
being an undesirable ingredient for use in most edible and pharmaceutical
preparations.
Avocado oil unsaponifiables (a source of phytosterol) can be used instead of
cholesterol as a bilayer modulator and provides many cosmetic, dermatological
and
pharmaceutical benefits. For example, it has a soft waxy consistency that
confers a creamy
texture to skin care products in addition to its moisturizing effects. Avocado
oil
unsaponifiables are also non-cytoxic, non-irritating and edible.
Accordingly, an object of the present invention is to provide a method of
making
paucimellar lipid vesicles using materials which are edible and/or have
cosmetic,
dermatological and pharmaceutical benefits.
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Another object of the invention is to provide paucilamellar lipid vesicles
which
contain a blend of at least one non-phospholipid amphiphile as the primary
structural material
of the bilayers and phytosterol supplied by avocado oil unsaponifiables as a
modulator.
A further object of the invention is to provide a method of producing
paucimellar
lipid vesicles which readily encapsulate water immiscible oily materials and
are
manufactured from relatively inexpensive materials.
These and other objects and features of the invention will be apparent from
the
following description and the claims.
Summary of the Invention
The present invention features paucilamellar lipid vesicles having 2-10
bilayers
1 ~ surrounding an amorphous central cavity which is substantially filled with
an oily material.
The lipid bilayers contain at least one non-phospholipid amphiphile as the
primary lipid and
phvtosterol supplied by avocado oil unsaponifiables as a modulator. The lipid
bilayers may
further contain a negative charge producing agent, such as dicetyl phosphate,
oleic acid,
stearic acid, or mixtures thereof or a positive charge producing agent, such
as quaternary
ammonium compounds. The term "primary lipid", as used herein, means that this
lipid is the
major lipid, by weight, forming the structure of the lipid bilayers.
In a preferred embodiment, the primary non-phospholipid amphiphile is selected
from
the group consisting of polyoxyethylene fatty esters, polyoxyethylene fatty
acid ethers,
diethanolamides, long chain acyl hexosamides, long chain acyl amino acid
amides, long
chain acyl amides, polyoxyethylene derivatives of fatty acid esters having 10-
20 oxyethylene
groups, polyoxyethylene 20 sorbitan mono- or trioletate, polyoxyethylene
glyceryl
monostearate with 1-10 oxyethylene groups, and glycerol monostearate. In
another preferred
embodiment, the bilayers further contain a phospholipid, a glycolipid, and
mixtures thereof.
In yet another preferred embodiment, the primary non-phospholipid amphiphile
is
selected from the group consisting of betaines and anionic sarcosinamides.
In still another preferred embodiment, the bilayers contain both a primary non-
phospholipid amphiphile selected from the group consisting of C 12-C 1 g fatty
alcohols, C 12-
C 1 g glycol monoesters, C 12-C 1 g g~yceryl mono- and diesters, propylene
glycol stearate,
sucrose distearate, and mixtures thereof; and a second non-phospholipid
amphiphile selected
from the group consisting of quaternary dimethyldiacyl amines, polyoxyethylene
acyl
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alcohols, polyglycerols, sorbitan fatty acid esters, polyoxyethylene
derivatives of sorbitan
fatty acid esters, fatty acids and their salts, and mixtures thereof.
The present invention further relates to a method of forming the paucilamellar
S lipid vesicles of the invention. A lipophilic phase containing at least one
non-
phospholipid amphiphile is first prepared and then blended with avocado oil
unsaponifiables and any other oily material to be encapsulated into the
vesicle to form a
lipid phase. This lipid phase is then shear mixed with an aqueous phase
containing an
aqueous-based hydrating agent and any aqueous soluble material to be
encapsulated into
the vesicle to form lipid vesicles. "Shear mixing" is defined as the mixing of
the lipid
phase with the aqueous phase under turbulent or shear conditions which provide
adequate mixing to hydrate the lipid and form lipid vesicles. "Shear mixing"
is achieved
by liquid shear which is substantially equivalent to a relative flow rate for
the combined
phase of about 5-30m/s through a 1 mm orifice.
In order to achieve the proper blending necessary to form the paucilamellar
vesicles of the present invention, all of the materials are normally in
flowable state. This
is easily achieved by elevating the temperature of the lipid phase in order to
make it
flowable followed by carrying out the shear mixing between the lipid phase and
the
aqueous phase at a temperature such that both phases are liquids.
In an aspect of the present invention there is provided a paucilamellar lipid
vesicle
having 2-10 bilayers surrounding an amorphous oil-filled central cavity, a
portion of the
oil filling of said oil-filled central cavity being supplied by avocado oil
unsaponifiables,
wherein each of said bilayers contains at least one non-phospholipid
amphiphile selected
from the group consisting of polyoxyethylene fatty esters, polyoxyethylene
fatty acid
ethers, diethanolamides, long chain acyl hexosamides, long chain acyl amino
acid
amides, long chain acyl amides, polyoxyethylene derivatives of fatty acid
esters having
10-20 oxyethylene groups, POE (20) sorbitan mono- or trioletate,
polyoxyethylene
glyceryl monostearate with 1-10 oxyethylene groups, and glycerol monostearate
as the
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primary lipid in said bilayers, and phytosterol supplied by said avocado oil
unsaponifiables as a modulator in said bilayers.
In a further aspect of the present invention there is provided a method of
forming
a paucilamellar lipid vesicle having 2-10 lipid bilayers surrounding an oil-
filled
amorphous central cavity, said method comprising the steps of: A. preparing a
lipophilic
phase containing at least one non-phospholipid amphiphile selcted from the
group
consisting of polyoxyethylene fatty esters, polyoxyethylene fatty acid ethers,
diethanolamides, long chain acyl hexosamides, long chain acyl amino acid
amides, long
chain acyl amides, polyoxyethylene derivatives of fatty acid esters having 10-
20
oxyethylene groups, POE (20) sorbitan mono- or trioletate, polyoxyethylene
glyceryl
monostearate with 1-10 oxyethylene groups, and glycerol monostearate as the
primary
lipid to be incorporated into said bilayers; B. blending said lipophilic phase
with
avocado oil unsaponifiables and any other oily material to be encapsulated
into said
vesicle to form a lipid phase; C. preparing an aqueous phase of an aqueous-
based
hydrating agent and any aqueous soluble material to be encapsulated into said
vesicle;
and D. shear mixing said lipid phase with said aqueous phase to form said
lipid vesicle,
without the formation of a separable lamellar phase, whereby said avocado oil
unsaponifiables partition so that phytosterol from said avocado oil
unsaponifiables is
incorporated into the bilayers of said lipid vesicle and the remaining
components of said
avocado oil unsaponifiables are entrapped in the amorphous central cavity of
said lipid
vesicle.
In yet a further aspect of the present invention there is provided a
paucilamellar
lipid vesicle having 2-10 bilayers surrounding an amorphous oil-filled central
cavity,
wherein each of said bilayers contains at least one non-phospholipid
amphiphile selected
from the group consisting of polyoxyethylene fatty esters, polyoxyethylene
fatty acid
ethers, diethanolamides, long chain acyl hexosamides, long chain acyl amino
acid
amides, long chain acyl amides, POE (20) sorbitan mono- or trioletate, and
glycerol
monostearate as the primary lipid in said bilayers and phytosterol supplied by
avocado oil
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unsaponifiables, said avocado oil unsaponifiables partitioning in manufacture
of said
paucilamellar lipid vesicles, so that a sufficient amount of the phytosterol
from said
avocado oil unsaponifiables goes into said bilayers so as to stabilize said
bilayers and the
remainder of said avocado oil unsaponifiables goes into said amorphous central
cavity.
Preferably, said avocado oil unsaponifiables are provided in an amount of 20
to
65% by weight of the total weight of lipids in said paucilamellar lipid
vesicle.
All of the materials used to form the vesicles of the invention can also be
used in
the methods of the invention. Other modifications of the methods and products
will be
apparent from the following description and claims.
Detailed Description of the Invention
The lipid vesicles of the invention are paucilamellar lipid vesicles
characterized
by two to ten lipid bilayers or shells with small aqueous volumes separating
each
substantially spherical lipid shell. The innermost lipid bilayer surrounds a
large,
amorphous central cavity which is substantially filled with an oily solution.
The lipid bilayers of the vesicles contain a blend of at least one non-
phospholipid
amphiphile as the primary lipid of the bilayers and phytosterol supplied by
avocado oil
unsaponifiables which acts as a modulator. The avocado oil unsaponifiables
provides
two distinct benefits: first, it acts as a source of phytosterol for the
bilayers, and second,
it acts as a source of triglycerides which substantially fill the amorphous
central cavity of
the vesicles and serve as a moisturizer. This oily material also acts as a
vesicle stabilizer.
The central cavity may further contain other oily materials.
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The following Examples will clearly illustrate the efficacy of the invention.
Fxa~ male 1
In this Example, oil-filled lipid vesicles were formed using avocado oil
unsaponifiables obtained from Croda Inc., Parsippany N.J., with and without
additional
cholesterol, as a component of the lipid bilayers. Propylene glycol stearate
was used as the
primary amphiphile of the lipid bilayers. Polysorbate 60~(polyoxyethylene 20
sorbitan
monostearate) and/or stearyl alcohol were added to Samples A, C and D as
secondary
amphiphiles or spacers.
TABLE 1
Composition Sample
(grams) A B C D
Propylene Glycol Stearate 1.75 2.5 2.5 2.5
Stearyl Alcohol 0.35 0.5 0.5
Polysorbate 60 0.25 0.35
Cholesterol 0.5
Avocado Oil Unsaponifiables*4.0 2.5 2.5 2.5
Water 28.6 30 30 29
* 1 gram Avocado oil
unsaponifiables contains
about 0.3 grams phyrtosterol
In this Example, oil-filled vesicles were formed using the hot loading
technique
described in United States Patent No. 4,911,928. Briefly, the vesicles were
hot loaded
by heating the lipid phase consisting of avocado oil unsaponifiables and the
appropriate
~0 amphiphile(s) to 85°C, and then hydrating the lipid phase by the
aqueous phase at
65°C.
Hydration to form lipid vesicles was achieved by shear mixing the lipid and
aqueous
phases using two 60 cc syringes, connected by a stopcock. The lipid and
aqueous phases
were blended from one syringe to the other, forming vesicles in two minutes or
less.
. However, in this and the following Examples, any method of achieving the
proper shear
could be used. Preferably, a flow device such as the NovaMixTM vesicle former
is used. The
basic details of the NovaMixT"' system are described in United States Patent
No. 4.895.452.
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After processing to form lipid vesicles, sample B had a cottage cheese-like
consistency, while sample C had only partially hydrated lipid and clear water.
These samples
were not examined further.
S After processing to form lipid vesicles, samples A and D had a smooth,
lotion-like
consistency. Microscopic examination of these samples showed nice, small,
spherical
vesicles with maltese crosses, indicating multiples concentric lipid bilayers.
The mean
diameters of these vesicles measured 1460 nm and 913 nm respectively. When
centrifuged at
3500 rpm for 30 minutes, samples A and D both showed some separation, probably
due to an
excess of water. Sample A, which contained 4.0 grams of avocado oil
unsaponifiables with
no additional cholesterol, contained a slightly better, more homogenous
population of
vesicles than did sample D, which contained cholesterol and only 2.5 grams of
avocado oil
unsaponifiables.
This Example shows that avocado oil unsaponifiables, preferably ranging from
20-6~
percent by weight of the lipid, can be used along with or, more preferably,
instead of
cholesterol in the formation of oil-filled lipid vesicles. Avocado oil
unsaponifiables provides
the advantage of acting both as a source of phytosterol in the lipid bilayers,
as well as a
source of triglycerides which partially fill the central cavity of the
vesicles, serving as a
moisturizing agent
Example 2
In this Example, samples A-C were designed to form oil-filled paucilamellar
vesicles
using as the primary structural components of the lipid bilayers an amphiphile
selected from
the group consisting of glyceryl dilaurate, glyceryl monostearate, or glyceryl
distearate, and
phytosterol from avocado oil unsaponifiables (obtained from Croda Inc.,
Parsippany, N.J.).
Samples B and C also contained a secondary amphiphile which acted as a spacer
molecule,
consisting of either Polysorbate 60 (polyoxyethylene 20 sorbitan monostearate)
or Brij 76
(polyoxyethylene 10 stearyl alcohol).
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TAB
Vesicle Components
(grams) A B C
Brij 76'' 1.6
Glyceryl Dilaurate 3.0
Glyceryl Monostearate 2.55
Glyceryl Distearate 2.0
Polysorbate 60~ 0.67
Avocado Oil Unsaponifiables* 4.0 4.0
3.0
Water 30.0 35.0 40.0
* 1 gram of Avocado Oil Unsaponifiables contains approximately
0.3 grams of phytosterol.
Oil-filled vesicles were formed using the hot loading technique described in
Example
l, except that the aqueous phase was heated to 70°C instead of
65°C.
After processing to form lipid vesicles, all three Samples had a nice fluid
consistency.
Upon microscopic examination, Sample A had two populations of vesicles
consisting of
small, birefringent vesicles with maltese cross patterns (indicating multiple
concentric
bilayers) and larger, aggregated vesicles. Sample B contained small, hetro-
sized, birefringent
vesicles with maltese cross patterns. Sample C contained the best vesicles of
the three
samples and was made up of homogenous, small, birefringent vesicles with
maltese cross
patterns. The mean particle diameter of the vesicles of Samples A-C, measured
by Coulter
Counter (Coulter Counter Electronics Corp., Miami, FL), was approximately 1190
nm, 1420
nm and 380 nm, respectively.
After centrifugation at 3500 rpm for 15 minutes, Sample A (containing no
secondary
amphiphile) separated into two phases consisting of approximately 25 ml of
turbid solution at
the bottom of the Sample and approximately 10 ml of creamy solution at the
top. Samples B
and D showed no separation, probably due to the addition of a secondary
amphiphile.
These results show that paucilamellar lipid vesicles can be formed using
avocado oil
unsaponifiables instead of cholesterol or other membrane modulators, along
with an
amphiphile, to form the lipid bilayers of paucilamellar vesicles. The addition
of a secondary
,,
amphiphile, preferably Brij 76 (~ Sample C), improves the size and shape of
the vesicles.
Avocado oil unsaponifiables provides the advantage of acting both as a source
of phyosterol
in the lipid bilayers, as well as a source of triglycerides which are
encapsulated in the central
cavity and serve as a moisturizing agent.
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Example s
In this Example, oil-filled paucilamellar lipid vesicles were formed using
avocado oil
unsaponifiables (obtained from Croda Inc., Parsippany, N.J.) along with a
primary .
amphiphile consisting of either polyoxyethylene 2 cetyl ether (Brij 52) or
polyoxyethylene 9
glyceryl monostearate (POE 9 GMS). For Samples B and C, phosphate buffer
saline (PBS) .
was used instead of water as the hydrating agent.
TABLF~
IO
Vesicle Components Sample
(grams) A B C D
j, 1.8 1.8
Brij 52
POE 9 GMS 2.7 2.7
Avocado Oil Unsaponifiables*1.2 1.2 1.7 1.7
Water 16.0 13.0
pBS 16.0 13.0
1 S * 1 gram of Avocado Oil Unsaponifiables contains approximately
0.3 gm of phytosterol.
Oil-filled vesicles were formed using the hot loading technique described in
Example
1, except that the lipid phase was heated to 70°C and hydrated by the
aqueous phase at 65°C.
20 Hydration to form lipid vesicles was achieved using 20cc syringes in place
of the 60cc
syringes used in Example 1.
After processing for lipid vesicles, Samples A and B were thick and viscous,
while
Samples C and D were fluid.
Microscopic examination of all four samples showed very nice, small, spherical
vesicles. The mean particle diameter of the vesicles of Samples A-D were
1040nm, 809 nm,
444 nm and 430 nm, respectively.
This Example shows that the combination of POE 9 GMS and avocado oil
unsaponifiables forms better vesicles, both in shape and in consistency of
formulation, than
X
does the combination of Brij52"and avocado unsaponifiables. This Example also
shows that
PBS can be used instead of water as a hydrating agent.
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F~,ample 4
In this Example, a variety of different primary amphiphiles were used in
combination
with avocado
oil unsaponifiables
(obtained
from Croda
Inc., Parsippany,
N.J.) to
form the
lipid bilayers For each
of oil-filled Sample,
paucilamellar vesicles
vesicles. were
made
with
- phytosterol, 15% by weight
supplied of bilayer
by avocado
oil unsaponifiables,
being
mat erial and 3.8% by weight of
the total vesicle.
I O TABLE 4
Avacado Oil
Unsaponifia Wate
bles* r
A POE10 Cetyl Alcohol (Brij 1.7 gm 1.0 gm 16 ml
56)"
B POE2 Stearyl Alcohol (Brij 1.7 gm 1.0 gm 16 ml
72) ,~
C POE10 Stearyl Alcohol (Brij 1.7 gm 1.0 gm 16 ml
76) ~~
D POE10 Oleyl Alcohol (Brij 1.7 gm 1.0 gm 16 ml
97)~
E POE4 Lauryl Alcohol (Brij 1.7 gm 1.0 gm 16 ml
30~'
F POE2 Oleyl Alcohol (Brij 92) 1.7 gm 1.0 gm 16 ml
~
G Y 1.7 gm 1.0 gm 16 ml
POE20 Sorbitan Monostearate
(Tween 6~~
H POE20 Sorbitan Monooleate 1.7 gm 1.0 gm 16 ml
(Tween 80)
I POE8 Stearate (Myrj 45) 1.7 gm 1.0 gm 16 ml
J DEA Lactic Amide (Mona 150 1.7 gm 1.0 gm 16 ml
LWA)
K DEA Lauric Amide (Mona 150 1.7 gm 1.0 gm 16 ml
LWA)
L DEA Linoleic Amide (Mona 15-70w)1.7 mg 1.0 gm 16 ml
* 1 gram of Avocado Oil Unsaponifiables contains approximately
0.3 gm of phytosterol
*POE is polyoxyethylene
*DEA is diethanolamide
Oil-filled vesicles were formed using the hot loading method described in
Example 1,
except that the lipid phase was heated to 70°C and hydrated by the
aqueous phase at 60°C.
Hydration to form lipid vesicles was achieved using 20cc syringes in place of
the 60cc
syringes used in Example 1. After processing to form lipid vesicles, the
following results
were observed:
Sample A (Brij 56'and avocado oil unsaponifiables) had a fluid consistency.
Upon
microscopic examination, many heterogenous, but small vesicles were visible.
After
centrifugation at 3500 rpm for 15 minutes, no separation was observed, but a
small amount of
creaming formed on top of the Sample. Mean particle size of the vesicles,
measured by
Coulter Counter, was 254 nm.
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Sample B (Brij 72~and avocado oil unsaponifiables) had a lotion-like
consistency.
Upon microscopic examination, many heterogenous vesicles were visible. After
centrifugation at 3500 rpm for 15 minutes, no separation was observed. Mean
particle size of
the vesicles, measured by Coulter Counter, was 765 nm.
10
Sample C (Brij 76~~and avocado oil unsaponifiables) had a fluid consistency.
Upon
microscopic examination, very nice small vesicles were visible. After
centrifugation at 3500
rpm for 15 minutes, 2 ml of hazy solution separated as infernatant. Mean
particle size of the
vesicles, measured by Coulter Counter, was 281 run.
Sample D (Brij 9'7~and avocado oil unsaponifiables) had a very fluid
consistency.
Upon microscopic examination, both very nice small vesicles and some large
vesicles were
visible. After centrifugation at 3500 rpm for 15 minutes, no separation was
observed, but a
small amount of creaming formed on top of the Sample. Mean particle size of
the vesicles,
measured by Coulter Counter, was 151 nm.
Sample E (Brij 30jand avocado oil unsaponifiables) had a very fluid
consistency.
Upon microscopic examination, both very nice small vesicles and some large
vesicles were
visible. After centrifugation at 3500 rpm for 15 minutes, no separation was
observed, but a
small amount of creaming formed on top of the Sample. Mean particle size of
the vesicles,
measured by Coulter Counter, was 348 nm.
Sample F (Brij 92 and avocado oil unsaponifiables) had a fluid consistency.
Upon
microscopic examination, nice spherical vesicles were visible. After
centrifugation at 3500
rpm for 15 minutes, 1 ml of turbid aqueous solution separated as infernatant.
Mean particle
size of the vesicles, measured by Coulter Counter, was 381 nm.
Sample G (Tween 60 and avocado oil unsaponifiables) had a very fluid
consistency.
Upon microscopic examination, extremely small homogenous vesicles were
visible. After
centrifugation at 3500 rpm for 15 minutes, no separation was observed, but a
small amount of
creaming formed on top of the Sample. Mean particle size of the vesicles,
measured by
Coulter Counter, was 151 nm.
Sample H (Tween 80 and avocado oil unsaponifiables) had the same consistency
and
size vesicles as Sample G. After centrifugation at 3500 rpm for 15 minutes, no
separation
was observed. Mean particle size of the vesicles, measured by Coulter Counter,
was 164 nm.
Sample I (Myrj 45 and avocado oil unsaponifiables) had a fluid consistency.
Upon
microscopic examination, very nice looking small vesicles were visible. After
centrifugation
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at 3500 rpm for 1 ~ minutes, no separation was observed, but the Sample took
on a lotion-like
consistency. Mean particle size of the vesicles, measured by Coulter Counter,
was 310 nm.
Sample J (Mona 150 LWA and avocado oil unsaponifiables) had a creamy
~ consistency. Upon microscopic examination, the vesicles appeared similar to
those of
Sample I (small and nice looking). After centrifugation at 3500 rpm for 15
minutes, no
separation was observed. Mean particle size of the vesicles, measured by
Coulter Counter,
was 252 nm.
Sample K (Mona 150 LWA and avocado oil unsaponifiables) had a fairly thick,
creamy consistency. Upon microscopic examination, nicely shaped heterogenous
vesicles
were visible. After centrifugation at 3500 rpm for 15 minutes, no separation
was observed.
Mean particle size of the vesicles, measured by Coulter Counter, was 644 nm.
1 ~ Sample L (Mona 15-70w and avocado oil unsaponifiables) had the same
consistency
as Sample K. Upon microscopic examination, the vesicles also appeared similar
to those of
Sample K, except that they were smaller. After centrifugation at 3500 rpm for
1 S minutes, no
separation was observed. Mean particle size of the vesicles, measured by
Coulter Counter,
was 218 nm.
This Example shows that avocado oil unsaponifiables can be used in combination
with a variety of primary amphiphiles, in particular the Tween family of
ethoxylated sorbitan
J.
fatty acid esters, the Brij family of polyoxyethylene fatty ethers, the Myrj
family of
polyoxyethylene derivatives of stearic acid, and the Mona family of
diethanolamides to form
2~ good lipid vesicles. None of the samples showed birefringence, probably due
to the small
particle size of the vesicles.
Exam lie 5
In this Example lipid vesicles for use in hair conditioners were formed. The
primary
amphiphile making up the lipid bilayers consisted of glyceryl distearate in
Sample A and
polyoxyethylene (8) stearate in Sample B. Stearyl alcohol was added as a
secondary
amphiphile. The lipid bilayers also contained phytosterol from avocado oil
unsaponifiables
(supplied by Croda Inc., Parsippany, N.J.). Distearyldimonium chloride was
used as a
positive charge producing agent.
3~
In the aqueous phase, sodium laurel sulfate (30%) was used as a secondary
emulsifier,
along with methyldibromo glutaronitrile phenoxyethenol
polyquaterniurn 7 as a preservative. Cetyl trimethyl ammonium chloride was
used as a
positive charge producing agent.
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(% by ght)
wei
A B Lipid Phase
1.5 0.5 Stearyl Alcohol
2.0 Glyceryl Distearate
1.7 Polyoxyethylene (8) Stearate
3.33 1.0 Avocado Oil Unsaponifiables*
2.5 2.5 Distearyldimonium Chloride
Aqueous Phase
0.5 0.5 Sodium Laurel Sulfate 30%
0.1 0.1 Methyldibromo Glutaronitrile
Phenoxyethenol
Polyquaternium 7
0.1 2.0 Cetyl Trimethyl Ammonium Chloride
88.0 91.7 Deionized Water
* 1 gram of Avocado Oil Unsaponifiables contains approximately
0.3 gm of phytosterol
The lipid vesicles were hot loaded according to the method described in
Example 1.
Sample A was processed using a hydration ratio of 1 part lipid at 80°C
to 9.5 parts aqueous at
70°C. Sample B was processed using a hydration ratio of 1 part lipid at
90°C to 16.5 parts
aqueous at 70°C.
After processing to form lipid vesicles, both Samples A and B had a creamy
consistency, appropriate for use as a hair conditioner. Upon microscopic
examination, the
vesicles of both Samples were very good and homogenous.
This Example shows that avocado oil unsaponifiables, which acts both as a
structural
component of lipid vesicles by supplying phytosterol to the lipid walls, as
well as a
moisturizing agent by supplying triglycerides to the central cavity can be
used along with
amphiphiles which also have cosmetic (e.g., moisturizing) properties, such as
glyceryl
distearate and polyoxyethylene 8 stearate, to form good lipid vesicles
suitable for use in
cosmetics. Other useful materials (i.e., emulsifiers and preservatives) can
also be added to
the aqueous portion of the lipid vesicles, such as sodium laurel sulfate (30%)
and
methyldibromo glutaronitrile phenoxyethenol polyquaternium 7.
xam~le 6
In this Example, lipid vesicles were formed for use in a skin rejuvenating
cream.
Polyoxyethylene 8 stearate was used as the primary amphiphile and stearyl
alcohol, stearyl
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alcohol-Ceteareth 20 and cetearyl alcohol-Ceteareth 20 were used as the
secondary'
amphiphiles making up the lipid bilayers. Avocado oil unsaponifiables was also
added to
provide phytosterol to the bilayers and triglycerides to the central cavity. A
variety of other
moisturizing agents were also added to the lipid phase, such as shark liver
oil, petrolatum
lanolin-lanolin alcohol, benzoic acid alkyl esters and cetyl acetate-
acetylated lanolin alcohol,
all of which were encapsulated in the central core of the lipid vesicles.
Tocopherol
concentrate (vitamin E) and BHA (butylated hydroxy anisol) were added to the
lipid phase as
antioxidants.
The aqueous portion of the lipid vesicles contained glycerin (99%) and
butylene
glycol as humectants, sodium DL2 pyrrolidone 5 carboxylate, aloe vera
concentrate, SRF
(skin respiratory factor) and collagen as moisturizers, di sodium EDTA as a
chelating agent,
and methyldibromo glutaronitrile phenoxyethenol polyquaternium 7 as an
antibacterial agent.
by Weight LIPID PHASE
0.5 Shark Liver Oil
0.1 Petrolatum-Lanolin-Lanolin Alcohol
0.5 Benzoic Acid-C12 - 15 Alkyl Esters
0.1 TOCOPHEROL Concentrate (Vitamin
E)
1.5 Copolyol
3.0 Stearyl Alcohol - Ceteareth - 20
0.~ Stearyl Alcohol
1.0 Cetearyl Alcohol - Ceteareth -
20
1.7 Polyoxyethylene (8) Stearate
1.0 Avocado Oil Unsaponifiables
0.04 Fragrance
0.1 BHA
1.0 Cetyl Acetate - Acetylated Lanolin
Alcohol
AQUEOUS PHASE
4.0 Glycerin 99%
6.0 Butylene Glycol
1.0 Sodium DL2 Pyrrolidone S - Carboxylate
0.2 Aloe Vera Concentrate
0.1 Di Sodium EDTA
0.1 Collagen
0.2 Methyldibromo Glutaronitrile Phenoxyethenol
Polyquaternium 7
0.05 SRF Powder
77.31 Deionized Water
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The lipid vesicles were hot loaded according to the method described in
Example I .
A hydration ratio of 1 part lipid at 80°C to 16.5 parts aqueous at
70°C was used. After
processing to form lipid vesicles, the sample had a creamy consistency,
appropriate for use as
a skin rejuvenating cream. Upon microscopic examination, the vesicles were
very good
S looking and homogenous.
This Example shows that a variety of amphiphiles which have cosmetic
properties
(i.e., moisturizers) can be used in combination with avocado oil
unsaponifiables to form the
lipid bilayers and to fill the central cavity of vesicles for use in skin
creams. Avocado oil
unsaponifiables provides the advantage of acting both as a good structural
component of
vesicles by providing phytosterol to the lipid bilayers, as well as a
moisturizing agent by
providing triglycerides to the central cavity.
Examnlg 7
In this Example, lactic acid carrying lipid vesicles were formed for use in
.dermatologicals. The lipid bilayers of the vesicles were made up of glycerol
distearate as the
primary amphiphile, polyoxyethylene 10 stearyl ether, stearyl alcohol-
Ceteareth 20, cetearyl
alcohol-Ceteareth 20 and stearyl alcohol as secondary amphiphiles, and
phytosterol supplied
by avocado oil unsaponifiables. Other materials included in the lipid phase to
be
encapsulated in the central core of the vesicles were lactic acid (88%) (a
dead skin cell
remover), and cetyl acetate-acetylated lanolin alcohol, alkyl lactate and
octyl hydroxystearate
(skin moisturizers).
The aqueous phase included methyl paraben as a preservative, Bronopol
(methyldibromo glutaronitrile phenoxyethenol polyquaternium 7) and propyl
paraben as
antibacterials, glycerin (96%) as a humectant, and Polysorbate
80~(polyoxyethylene 20
sorbitan monooleate) as a secondary emulsifier.
TABLE 7
by Weight
LIPID PHASE
5.7 Lactic Acid 88%
1.4 Polyoxyethylene 10 Stearyl Ether
3.3 Avocado Oil Unsaponifiables
6.3 Octyl Hydroxystearate
2.8 Glycerol Distearate
3.0 Stearyl Alcohol - Ceteareth 20
1.0 Cetearyl Alcohol - Ceteareth 20
1.0 Stearyl Alcohol
1.0 Cetyl Acetate and Acetylated Lanolin
Alcohol
1.5 C 12-15 Alkyl Lactate
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AQUEOUS PHASE
0.2 Methyl Paraben
4.0 Glycerin 96%
S 1.24 Sodium Hydroxide
0.03 Propyl Paraben
0.10 Sodium Chloride
f
Y_
0.75 Polysorbate 80
0.05 Bronopol
4.0 Silicone Emulsion
0.2 Fragrance
62.93 Deionized Water
The lipid vesicles were hot loaded according to the method described in
Example 1.
A hydration ratio of 1 part lipid at 70°C to 16.5 parts aqueous at
60°C was used. After
processing, the sample had a creamy consistency, appropriate for use in
dermatological
preparations. Upon microscopic examination, the vesicles were very good
looking and
homogenous.
This Example shows that avocado oil unsaponifiables can be used with
amphiphiles
and other materials having dermatological properties to form lipid vesicles
for use in
dermatologicals. Avocado oil unsaponifiables provides the advantage of acting
both as a
source of phytosterol for the lipid bilayers, as well as a source of
triglycerides (moisturizing
agent) to be encapsulated in the central cavity of the vesicles.
The foregoing Examples are merely illustrative and those skilled in the art
may be
able to determine other materials and methods which accomplish the same
results. Such
other materials and methods are included within the following claims.
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