Note: Descriptions are shown in the official language in which they were submitted.
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STABLE HERBAL DENTIFRICE
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to oral health care
products, particularly dentifrices, more particularly
gel dentifrices, containing fluoride and baking soda.
This invention also relates to methods of making
dentifrices and methods of using dentifrices.
2. Description of Related Art
Dentifrices have long been known and used to
clean teeth and to combat plaque. Formulators
constantly seek new ways to improve the attractiveness
of a dentifrice to encourage compliance with an oral
health care regimen. In addition to flavor
improvements that have been made over the years,
various visual improvements over a traditional white
paste have also been made.
One of the most striking improvements in
visual appeal came with the introduction of dentifrice
gels. In place of an opaque paste, the dentifrice
offered a transparent or translucent gel, which
provided strong appeal to the public and encouraged
compliance with daily oral health care.
Another area of recent interest for
consumers has been the use of increasing numbers of
"natural" ingredients in products generally, including
dentifrices. Thus, dentifrices have recently taken to
using baking soda, a traditional dentifrice
ingredient, as a cleaning agent in dentifrices.
One problem with baking soda as a dentifrice
ingredient, however, is stability. Baking soda,
sodium bicarbonate, has a tendency to break down when
associated with water., Thus, shelf life of baking
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soda dentifrices can be unacceptably brief.
U.S. Patent No. 3,937,804 to Delaney et al.,
issued February 10, 1976, (along with its counterpart
patent, U.S. Patent No. 3,943,240, issued March 9,
1976, both assigned to Colgate-Palmolive Company) is
an example of a baking soda dentifrice in which at
least about 20%, and preferably 30%, sodium
bicarbonate is mixed with water, a polyol humectant, a
gelling or thickening agent and fluoride. The
dentifrice has a granular textured appearance due to
macroscopic crystalline bicarbonate granules in an
otherwise smooth continuous matrix. Stability appears
to be maintained because the baking soda is separated
from the water by forming large granules.
U.S. Patent No. 5,326,554 to Fitz, Jr.,
issued July 5, 1994, is directed to oral compositions
containing sodium bicarbonate with sodium carbonate as
a stabilizing buffer.
U.S. Patent No. 4,623,536, issued November
18, 1986 and U.S. Patent No. 4,721,614, issued January
26, 1988, both to Winston et al., are' directed to a
toothpaste containing at least 60% sodium bicarbonate.
At least 30% of the bicarbonate has a particle size of
less than 25 microns, and bicarbonate is the sole
abrasive material in the dentifrice. The smaller
particle size is asserted to be the basis for the
claimed stability of the dentifrice. The Delaney
patents discussed above were distinguished because
those patents maintained stability by discontinuing
degassing of the dentifrice formulation prior to
complete deaeration. Thus, the Delaney patents
avoided unacceptable increases in pH levels.
U.S. Patent No. 4,943,429 to Winston et al.,
issued July 24, 1990, is directed to a dentifrice gel
containing sodium bicarbonate. The dentifrice
comprises up to about 60% by weight sodium bicarbonate
and at least about 22% of a humectant such as glycerol
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or sorbitol. Coarser grades of bicarbonate are
preferred at above 30% bicarbonate, since the coarser
(>about 149 microns) grades allow higher
concentrations of bicarbonate in a translucent gel.
Sodium bicarbonate and peroxide dentifrices
have been provided in split-tube designs to avoid
stability problems, as in U.S. Patent No. 5,456,902 to
Williams et al., issued t?~tober 10,1995.
Baking soda can also affect other
ingredients in the dentifrice, for good or ill. U.S.
Patent No. 5,180,576, for example (issued January 19,
1993) and U.S. Patent No. 5,318,773, (issued June 7,
1994), both to Winston et al., are directed to a
dentifrice incorporating pyrophosphate salts (tartar
control agents) and sodium bicarbonate in a
dentifrice. The combination of sodium bicarbonate and
pyrophosphate salts is asserted to have synergistic
properties, permitting,the use of reduced amounts of
pyrophosphate salts. Both ingredients, however, are
found as separate solids in the dentifrice, because
the bicarbonate "salts out" the pyrophosphate, leaving
little pyrophosphate to dissolve in the dentifrice
before use.
U.S. Patent No. 5,455,024 to Winston et al.,
issued October 3, 1995, is directed to a combination
of zinc oxide and sodium bicarbonate in a dentifrice.
In addition to baking soda, other natural
ingredients have been incorporated into dentifrices.
U.S. Patent No. 5,149,521 to Hirose et al., issued
September 22, 1992, for example, is directed to an
oral care composition such as a dentifrice. It
describes a composition comprising a powdery granule,
menthol, and basil, laurel, lavender or a lactone.
The combination produces a composition with a greatly
reduced powdery feeling during use.
An example of a dentifrice using "natural"
ingredients is found in U.S. Patent No. 5,472,684 to
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Nabi et al., issued December 5, 1995. In that patent,
a combination of thymol, eugenol and optionally a
sesquiterpene alcohol, such as farnesol, is claimed to
have antibacterial properties. The combination is
flavored with various natural agents such as:
chamomile, myrrh gum, rhatany~root, Australian Tea
Tree oil, eucalyptol, sage oil, Tulsi oil, Neem oil,
Eichinacea tincture, rosemary extract, goldenseed
extract, passion flower extract, turmeric extract,
betel nut extract, sunphenon tea extract, and
dandelion root extract.
U.S. Patent No. 4,812,306 to Cocherell et
al., issued March 14, 1989, is directed to a water-
free toothpaste having anise oil, clove oil,
sassafras, peppermint, glycerine, corn starch,
fluoride, sweetener, sodium lauryl sulfate, sodium
bicarbonate, and vegetable oil.
One problem with dentifrice gels containing
natural ingredients is syneresis, the tendency of the
liquid components to separate in a gel formulation.
This problem can be especially acute with a
formulation containing high solid levels, such as are
found in dentifrices containing baking soda.
This search for natural therapies is not
limited to dentifrices. U.S. Patent No. 4,670,264 to
Warren et al., issued June 2, 1987, for example,
discloses inhaled or transdermally delivered doses of
Nutmeg oil, Mace extract, Neroli oil, Valerian oil,
Myristicin, Isoelemicin or elemicin to reduce stress.
U.S. Patent No. 5,378,465 to Zeines, issued
January 3, 1995, is directed to an aqueous mouthwash
comprising echinacea, hydrastis canadensis,
sanguinaria canadensis, quercus albe, grapefruit seed
extract aloe vera juice, water, vegetable glycerin,
and peppermint oil.
U.S. Patent No. 5,043,153 to Vid~ki et al.,
issued August 27, 1991, is directed to a composition
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for the prevention and treatment of parondonthopathy.
The composition comprises an aqueous solution of
greater celandine, peppermint, marigold, thyme,
millfoil, and optionally chamomile, melilot leaf, and
clove or arnica.
U.S. Patent No. 4,670,263 to Noorlander,
issued June 2, 1987, is directed to a nontoxic
germicide comprising allantion (comfrey extract? and
optionally ascorbic acid, chlorophyll, or carotene.
l0 Along with baking soda and other "natural"
ingredients, dentifrice formulators continue to search
for more effective dentifrice ingredients. U.S.
Patent No. 5,578,294 to Lukacovic, issued November 26,
1996, is directed to oral compositions containing a
chelating agent and a hydrophobic anionic surfactant
in the absence of an enzyme. The chelating agent can
be a betaine and the surfactant is preferably a
combination of a sarcosinate and a tartarate. The
combination provides cleaning efficacy without soft
tissue desequamation. The enzyme is added in U.S.
Patent No. 5,320,831 to Majeti et al., issued June 14,
1994, which is directed to oral compositions
containing an enzyme, a surfactant, a chelating agent
and a fluoride ion source.
Despite the continued interest in these
areas, the art has yet to produce a stable, aqueous
dentifrice gel containing baking soda and other
natural ingredients combined with strong cleaning
properties.
SU1~1RRY OF THE INVENTION
The principal object of the present
invention therefore is to provide a stable, aqueous
dentifrice containing baking soda.
It is another object of the invention to
provide a dentifrice containing other natural
ingredients combined with strong cleaning properties.
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It is an advantage of the invention that the
dentifrice can be formulated as a gel.
It is another advantage of the invention
that it 'offers pleasant organoleptic qualities that
encourage regular use of the dentifrice.
Additional objects and advantages of the
invention will be set forth in part in the description
that follows, and in part will be obvious from this
description, or may be learned by practice of the
invention. The objects and advantages of the invention
may be realized and attained by means of the
instrumentalities and combinations particularly
pointed out in the appended claims.
To achieve the foregoing objects and
following the purpose of the invention, as embodied
and broadly described herein, the invention provides a
water-based dentifrice comprising baking soda and a
blend of natural ingredients.
To further achieve the foregoing objects and
by the purpose of the invention, the invention further
provides a method for making a dentifrice containing
water, baking soda and a blend of natural ingredients.
DESCRIPTION OF THE PREFERRED ~ODIMENTS
Reference will now be made in detail to the
presently preferred embodiments of the invention.
It has been generally difficult to formulate
a dentifrice or gel that contains a very high level of
solids, especially baking soda. This is because such
a high solid formulation is very prone to syneresis
and separation. When combined with natural
ingredients in liquid form, such as various tinctures
and extracts, the problem becomes even more difficult.
To overcome this problem, the invention
provides a dentifrice comprising baking soda, a blend
of natural ingredients, a flavor and other dentifrice
ingredients blended to form a stable dentifrice gel.
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One of the ingredients in the invention is
baking soda, sodium bicarbonate. The dentifrice of
the invention may comprise up to 60% by weight baking
soda. Preferably, however, the baking soda comprises
from about 35% to about 55% by weight of the
dentifrice and more preferably from about 40% to about
50% by weight of the dentifrice. In the most highly
preferred embodiment of the invention, baking soda
comprises about 45% by weight of the dentifrice.
Although particle size of the baking soda is not
critical to the invention, a preferred baking soda has
a particle size classification based on sieve
classification of 0-2% by weight retained on a No. 100
standard screen, 20-45% retained on a No. 200 standard
screen, and 60-100% retained on a No. 325 standard
screen.
In addition to baking soda, the dentifrice
comprises various natural ingredients. As used herein,
"natural" ingredients are those that are extracted or
derived, typically, but not necessarily, from plants
with minimal chemical alteration or processing. Many
such ingredients are available commercially and
include, but are not limited to, plant extracts,
pressings from herbs and flowers and distillations of
various materials.
One preferred combination of natural
ingredients is found in Parodontax~ brand toothpaste,
which comprises a combination of echinacea, myrrh,
chamomile, rhatany and sage.
3o Echinacea is also known as cone flower juice
or extract, and is commercially available. It is
described as the dried rhizome and roots of Echinacea
pallida, and comprises inulin, sucrose, betaine and
other ingredients.
Myrrh is described as being derived from
various species of Commiphora, and is a combination of
a gum, a volatile oil and a bitter principle. It is
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commercially available as a tincture, an alcohol
solution of a nonvolatile material.
Chamomile is made from the dried flower
heads of Anthemis nobilis. Its tincture is
commercially available and it comprises a bitter
glucoside, anthesterol, anthemene and a volatile oil.
Rhatany is also known as Krameria, and is
the dried root of Krameria triandra and other Krameria
plants. It comprises Krameriatannic acid and is
available commercially as a tincture.
Sage is also known as Salvia and is a widely
known flavoring agent. It is commercially available,
and its tincture is derived from dried leaves of
Salvia officinalis. It comprises 1-2.5% volatile oil,
resin, tannin, and bitter principles.
Although any natural ingredient,
particularly a natural ingredient that has a tendency
to separate or undergo syneresis with baking soda in a
gel, is within the scope of the invention, a blend of
natural ingredients is preferred. In a preferred
embodiment of the invention, the natural ingredient
blend is a combination of the Parodontax~ brand
dentifrice natural ingredients, although other natural
ingredients may be included.
In a preferred embodiment, the natural
ingredients may comprise up to about 5% by weight of
the dentifrice. In a more preferred embodiment, the
natural ingredients may comprise from about 1% by
weight to about 4% by weight of the dentifrice. In a
more preferred embodiment of the invention, the
natural ingredients may comprise from about 2% to
about 4% by weight of the dentifrice, and in a highly
preferred embodiment of the invention, the natural
ingredients may comprise about 3.6% by weight of the
dentifrice. In the Examples below, the natural
ingredients: Echinacea, Myrrh, Chamomile, Sage and
Rhatany comprise 3.596% by weight of the dentifrice
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formulations. Those skilled in the art will recognize
that 3.596% is well within the definition of "about
3.6%" as described herein.
In addition to the baking soda and the other
natural ingredients, the dentifrice may contain other
ingredients used in dentifrices, including gel
dentifrices.
A fluoride source may be included in the
dentifrice, such as sodium fluoride, stannous fluoride
or sodium monofluorophosphate. The fluoride source
typically comprises less than about 5%, more
preferably less than about 2% and most preferably less
than about 1% by weight of the dentifrice.
The dentifrice may comprise various
surfactants and detergents to aid in cleaning teeth.
Typical surfactants include betaines, such as
cocamidopropyl betaine, sodium lauroylsarcosinate,
lysolecithin and other detergents and surfactants
known in the art. Typically, these surfactants and
detergents are used in combinations and can comprise
up to about 5%, preferably up to about 3%, by weight
of the dentifrice.
The dentifrice of the invention may also
comprise polishing agents and abrasives. Examples of
such compounds include, but are not limited to,
colloidal silicon dioxide and amorphous silica. Such
compounds may be used alone or in combination, and
generally comprise from about 5% to about 15% by
weight of the dentifrice, preferably from about 6% to
about 12% by weight of the dentifrice, and most
preferably about 10% by weight of the dentifrice.
The dentifrice may also comprise a
humectant, such as sorbitol solution and glycerin.
The dentifrice may comprise from about 10% by weight
to about 40% by weight of the dentifrice, preferably
from about 20% to about 35% by weight of the
dentifrice, and preferably about 27% by weight of the
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dentifrice.
,The dentifrice may also contain a binder,
such as xanthan gum and a sweetener, such as sodium
saccharin. The binder generally comprises less than
about 1% by weight of the dentifrice, and the
sweetener may be adjusted to taste.
One advantage of the invention is that a
fairly large amount of a flavoring may also be
incorporated into the dentifrice. While the flavoring
may be a "natural" ingredient as discussed above, the
primary purpose of such an ingredient in the
dentifrice is to impart a pleasant flavor to the
dentifrice. Typically flavors include various mint
flavors, such as spearmint and peppermint. The
invention, however, is not limited to mint-flavored
dentifrices. The flavor may be up to about 5% by
weight of the dentifrice, although the flavor is
preferably up to about 3% by weight and more
preferably up to about 2% by weight of the dentifrice
formulation.
The dentifrice may also contain other known
ingredients used in dentifrices including, but not
limited to, whitening agents, anti-tartar agents and
desensitizing compounds.
Surprisingly, the formulation made in
accordance with the invention appears to be stable.
Although the invention is not limited by any
particular theory of operation, it appears that either
the combination of ingredients and/or the processing
of the ingredients make the product physically stable.
The dentifrice of the invention is made
substantially in the method set out in Example 1. The
water-soluble salts, i.e., the fluorides and the
sweeteners, are mixed in water. The humectants are
then added and the binder as well. The natural
ingredients are then added, followed by the abrasives,
detergents, and baking soda. Finally, the flavor oil,
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more detergent and additional natural ingredients are
added.
Although the following examples are intended
to illustrate some features and advantages of the
invention, they are not intended to limit the scope of
the appended claims.
Example 1
l0 A three thousand kilogram (3,000 Kg) batch
of a dentifrice in accordance with the invention was
manufactured by charging 274 Kg. water into a mixing
tank. 1.5 Kg of sodium saccharin and 9.3 Kg of sodium
fluoride were added and stirred until dissolved. 300
Kg. Glycerin and 510 Kg sorbitol were added to the
tank with continuous stirring. 15 Kg. xanthan gum was
slowly added with high shear mixing for about 30
minutes. 18.7 Kg myrrh tincture, 18.7 g chamomile
tincture and 28.5 Kg echinacea were slowly added to
the tank. 24 Kg. colloidal silicon dioxide was added
under high shear mixing followed by 300 Kg. amorphous
silica. Sodium sarcosinate (30 Kg) was then added
followed by 700 Kg. of sodium bicarbonate, 6 Kg.
coco-amidopropyl betaine, another 650 Kg. of sodium
bicarbonate, 57.8 Kg. peppermint oil, 15 Kg.
lysolecithin, 4.38 Kg. sage oil and 37.44 Kg. rhatany
tincture. The entire product was mixed thoroughly and
transferred for filling in suitable tubes. The
dentifrice had the formulation set forth in Table 1.
A portion of the formulation of Example 1
was placed into a 25 ml toothpaste tube and subjected
to a standard freeze/thaw test. The results are
reported in Table 2. Samples were also subjected to
stability tests at 40°C for four months, and the
results are reported in Table 3. "NR" in Tables 2 and
3 means no reading was taken. "Conforms" means that
the tested property fell within the design
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specification for the product. For appearance and
container integrity the design specification was no
obvious defect. b'or Munsell color, the design
specification was 7.5R 2/4; 7.5R 6/6.
Examples 2~ and 3
Dentifrices were prepared having the
formulations set forth in Table 1 using the procedure
set forth in Example 1. Portions of these
formulations were placed in 25 ml toothpaste tubes and
subjected to freeze/thaw tests and stability tests.
The results are reported in Table 3. Example 3 was
not tested for stability at 40° C.
Table 1 -- Dentifrice
Formulation
Ingredient Example Example Example
1 2 3
Weight Weight weight
% % %
Water 9.118 8.298 13.218
Sodium Fluoride 0.31 0.23 0.31
Sodium Saccharin 0.05 0.05 0.05
Coneflower Expressed 0.954 0.954 0.954
Juice
-- Stabilized
Myrrh Tincture 0.624 , 0.624 0.624
Chamomile Tincture 0.624 0.624 0.624
Rhatany Tincture 1.248 1.248 1.248
Sorbitol solution 70% 17 17 17
Colloidal Silicon Dioxide0.8 1.7 1.7
Amorphous Silica 10 10 5
Glycerin 96% 10 10 10
Xanthan Gum 0.5 0.5 0.5
Cocamidopropyl Betaine0.2 0.2 0.2
Sodium Lauroylsarcosinate1 1 1
Lysolecithin 0.5 0.5 0.5
Sodium Bicarbonate 45 45 45
Sage Oil 0.146 0.146 0.146
Peppermint Oil 1.926 1.926 1.926
Total 100.000 100.000 100.000
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Table 2
-- Freeze/Thaw
Data
Property Age: 5 Days 9 14
Tested 0 Days Days
1
Ex.
3-10
Days
Appearance1: Conforms1: Conforms1:Conforms 1:Conforms
2: Conforms2: Conforms2:Confozms 2:Coafosms
3: Conforms3: Conforms3:Conforms 3:Conforms
Munsell 1: Conforms1: Conforms1:Conforms 1:Conforms
l
C
o
or 2: Conforms2: Conforms2:Conforms 2:Conforms
3: Conforms3: Conforms3:Confoztna3:Conforms
pH 2: 8.76 2: 8.72 1:8.2 1:8.2
3: 8.71 3: 8.40 2:8.10 2:8.29
1: 1.56 1: 1.58 3:8.59 3:8.47
Viscosity 2: 1.76 2: 3.00 1:1.72 l:2.00
105)
(
x 3: 1.40 3: 1.24 2:3.80 2:5.20
cps
1: 1358 l: NR 3:2.40 3:1.80
Ionic 2: 1063 2: NR 1:NR 1:1282
Fl
id
uor
e 2:NR 2:1022
(ppm)
3: 1501 3: NR 3: 3:1433
NR
Sodium 1: 46t l: NR l:NR 1:45t
Bi -
b
t
car -
ona 2: 46.4ic 2: NR 2:NR ,2:46.11
e
wt ~
3: 46.71 3: NR 3 3:46.3f
NR
Container 1: Conforms1: NR 1: 1:Conforms
Inte NR
rit
g
y 2: Confozms2: Conforms2:Conforms 2:Conforms
3: Conforms3: Conforms3:Cpnforms 3:Conforms
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Table Stability
3 -- Testing
Property Age: 1 Month 3 Months 4 Months
Tested 0
Months
Appearance 1:Conforms 1: Conforms1:Conforms1:Conforms
2:Conforms 2: NR 2:Conforms2:Conforms
Munsell 1:Conforms 1: NR isNR 1:NR
Color
2:Conforms 2: NR 2:Conforms2:Conforms
pH 1:8.3 ~1: 8.8- l:8.4 1:8.2
2:8.76 2: NR 2:8.18 2:8.71
Viscosity 1:1.56 1: 1.98 l:2.44 l:3.00
tx 105)
cps 2:1.76 2: NR 2:6.30 2:7.75
Ionic 1:1358 1: 1344 1:1346 l:1368
Fluoride
lppm) 2:1063 2: NR 2:100p 2:1042
Sodium 1:46t is 46f 1:47f 1:48t
Bicarbonate
wt ~ 2:46.41 2: NR 2:47.71 2:47~t
Container 1:Conforms 1: Confosms1:Conforms1:Conforms
Integrity
2:Conforms 2s NR 2:Conforms2:Conforms
The purpose of the above description is to
illustrate some embodiments of the present invention
without implying a limitation. It will be apparent to
those skilled in the art that vario~~,~ modifications
and variations may be made in the apparatus or
procedure of the invention without departing from the
scope or spirit of the invention.
