Note: Descriptions are shown in the official language in which they were submitted.
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ENCAPSULATED FOAMING BATH COMPOSITION
Background of the Invention -
Bathing compositions which foam upon exposure to
warm water have found wide consumer acceptance due to the en-
hanced cleaning power of the foam produced and the cosmeticaspects such as appearance, fragrance and emollience which
can be imparted by the ingredients commonly incorporated
therein. Liquid bathing compositions, or "bath oils," are --
available as aqueous solutions or dispersions of mineral oil,
10 wheat germ oil, thickeners, fragrance and the like, which are -:
formulated to incorporate an effective amount of one or more
foam-producing surfactants.
Although such liquid compositions can function ef-
fectively to foam bath water, their general availability in
bulk (bottled~ form poses a number of proble~s. In the first
place, the appropriate amount must be pre-measured and poured
into the bath water stream, a step which often results in
waste or spillage. In the second place, bottled bath oils
are bulky and inconvenient to transport. Although the large
excesses of water employed to formulate the composltions pro-
mote their dispersion in the bath water, the water also in~
creases the shipping weight and storage space required for
liquid bath oil compositions.
Soft ~elatin encapsulation of a liquid foaming bath
oil composition could remedy these deficiencies, providing
easily-transportable "unit doses" of the composition in con-
centrated form. Soft, elastic (SEG) gelatin capsules are -
stable for long periods under ambient conditions while rup- -
turing readily when exposed to warm water. However, soft
gelatin, i.e. of type A or B, is chemically destabilized by
alkaline salts, leading to the leaking or bleeding of the
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capsule contents at elevated pH. This property has hereto-
fore prevented the soft gelatin enca~sulation of bath oil
compositions such as those which include commonly-used
foaming surfactants such as the fatty acid (diethanol)amides~
These surfactants exhibit pH's of greater than about 8.0-8.5
as measured in aqueous solution.
Therefore a need exists for a concentrated, high-
foaming bath composition which is suitable for, and com-
patible with, a soft gelatin shell.
Brief Description of the Invention
The present invention provides a cosmetic unit dos-
age form comprising a soft gelatin capsule containing a `-
liquid, foam-producing blend incorporating a fragrance and a
surfactant system. The surfactant system will include a
fatty acid (diethanol)amide, the diethanolamine salt OL a
fatty alcohol(ethylenoxy)sulfate and a fatty alcohol(ethyl-
onoxy)acetic acid. Although the diethanol amide and di- `
20 ethanol amine sulfate surfactants are basic (alkaline), it .~
has unexpectedly been found that the combination of these two ~-
su factants with a fatty alcohol(ethylenoxy)acetic acid sur- ---
factant is both high-foaming and compatible (non-reactive)
with soft gelatin. Although the mechanism of the interaction
of the surfactants is not known, the acidic surfactant is
able to counteract the expected degradation of the capsule
wall by -the basic surfactants without substantially reducing
the foaming power of the individual surfactants.
The liquid blend may contain minor amounts of adju- '
vants such as co-solvents and emollient oils but is otherwise
substantially water-free. As used herein, the term
"substantially water-free" is defined to mean that water pre- ~^
sent in the starting materials as provided by the manufac- --
turers or as acquired by hygroscopic attraction may be
present in the carrier mixture, as well as minor amounts of
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added water which are insu~ficient to deleteriously
effect the capsule wall stability.
The common chemical names of the surfactants
are in accord with the nomenclature system o~ the CTFA
Cosmetic Ingredient Dictionary (3rd Ed., 1982)~
The terms "foam-producing1' and "foamable" are
intended to indicate the capacity for producing a foam
layer upon contact with a warm aqueous medium such as
bath water.
Thus the present invention provides a
cosmetic unit dosage form comprising a soft gelatin
capsule containing a substantially water-free, liquid
blend consisting essentially of:
(a) from about 0.5% to about 10% of a fragrance;
(b) from about 30% to about 60% of a foamable mix-
ture of basic surfactants comprising a (diethanol)amine
salt of a fatty alcohol (ethylenoxy)sulfate and a fatty
acid ~diethanol)amide; and
(c) from about 30% to about 60% of an amount of a
foamable acidic surfactant comprising fatty alcohol-
(polyethylenoxy)acetic acid effective to render theliquid blend substantially non~reactive with said
gelatin capsule while maintaining the foam-producing
ability of the surfactants in aqueous media, said
percentages being percentages by weight based on the
total weight of the composition, said composition
containing not more than 10% by weigAt of other com-
ponents.
In another embodiment the in~ention provides a
cosmetic unit dosage form comprising a soft gelatin
capsule containing a substantially water-free liquid
blend consisting essentially of:
(a) about 005-10% fragrance;
(b) about 30-60% of a foamable mixture of basic
surfactants comprising a fatty acid (diethanol)amide
and a basic surfactant of the formula:
(C8-C22)alkyl(0CH2CH2)nOS03H.HN(CH2CH20H)2
wherein n is about 1-5;
-3a-
(c) abo~t 30-60% of a foamable acidic surfactant
comprising a surfactant of the general formula:
(c8-c~2)alkyl(ocH2cH2)mocH2co2
wherein m is about 3-15; and
(d) about 2-5~ propylene glycol said percentages
being percentages by weight based on the total weight
of the composition, said composition containing not
more than 10% by weight of other components.
Detailed Description of the Invention
The compositions of the present invention permit
the encapsulation, storage and delivery via soft
gelatin encapsulation of basic foamable surfactants
which would normally be chemically-incompatible with
soft gelatin if incorporated therein in a cosmetically
acceptable amount. To overcome this incompatibility,
the basic surfactants are combined with an amount of a
foamable acidic surfactant effective to render the
basic surfactants compatible with flexible, soft
gelatin capsules while maintaining the foam-producing
ability of the surfactants in aqueous media
substantially intact.
The basic, or high pH, surfactants useful in the
present foamable surfactant blend are selected from two
classes: the diethanol amine salts of fatty alcohol-
(ethylenoxy)sulfates and the diethanolamides of fattyacids.
Useful sulfate salts include those of the general
formula: higher (C8-C22)alkyl(0CH2CH2)nOSO3H.HN-
(C~l2CH20H)2, wherein n is about 1-5. Commercially-
available surfactants of this type include DEA-Laureth
Sulfate (available in combination with Cocamide DEA as
Monamine (trade mark) 779 from Mona Industries, Inc.,
Paterson, N.J.) and DEA-Myreth Sulfate (available in
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combination with Cocamide DEA as Standapol (trade
mark)Conc. 7023 from Henkel, Inc.). The commercially-
available preparations of these sulfate amine salts are
viscous liquids which exhibit pH's of about 8.5-9.0 in
10% aqueous solution.
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The high pH surfactants employed in the present
surfactant systems will also include at least one (diethanol)
amide of a saturated or unsaturated fatty acid of the general
formula: higher(C8-C22)alkylC=ON(CH2CH2OH)2. Useful amide
surfactants of this class include lauramide DEA (Monamid~
716, Mona Industries), cocamide DEA, linoleamide DEA and ole-
amide DEA. These amides are generally viscous liquids which
exhibit pH's of about 9.5-11.0 in 10% aqueous solutions.
The acidic, or low pH, surfactants employed to pre-
pare the present surfactant blends are selected from fattyalcohol(polyethylenoxy)acetic acids cf the general formula
higher(Cg-C22)alkyl(OCH2CH2)mOCH2CO2H wherein m is about 3-
15, preferably about 5-12. Commercially-available members of
this class include tridesceth-7-carboxylic acid (Sandopan~
DTC-Acid, Sandoz Chemical Co., East Hanover, N.J., C13-alkyl,
m=6) and isosteareth-6-carboxylic acid; C18-i-alkyl, m=3;
Sandopan3 TA-10. These surfactants are generally oily liq-
uids which exhibit pH's of about 3-~ in 1% aqueous solutions.
Preferably the acidic surfactant will be blended
with the basic surfactants in a weight ratio of about 0.5-
1.5:1, most preferabl~ about 1:1. The basic surfactant will
include at least one member of both the sulfate amine salt
and the fatty acid amide. Preferably, one or more of the
fatty acid a~ides will form the major proportion of the basic
surfactant blend, most preferably at least about 60% (e.g.,
60-80%) of the amide will be present.
The liquid blend of the present invention can also
include a minor amount of a C2-C4 diol or triol, preferably
propylene glycol and/or glycerin, which can function to ad-
just the viscosity of ~he surfacta~t blend and enhance itsrelease from the ruptured capsule.
~ inor but effective amounts of an odoriferous
ayent selected so as to be chemically-compatible with soft
gelatin and the above-described surfactants will be included
in the liquid blend. IJseful fragrances will include, for
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instance about 0.5-10~, preferably about 1-5% of floral oils
such as rose oil, lavender, lilac, jasmine, wisteria, citrus,
apple blossom, or compound bouquets such as spice, pine,
woody, oriental, and the like.
Minor amounts of other foam-compatible adjuvants,
such as dyes, emollient oils, biocides (preservatives and/or
disinfectants) and the like, may be introduced into the pres-
ent product in effective amounts either via the li~uid filler
or gelatin wall. When employed in the present products, such
adjuvants can be present at levels of up to about 5-10% by
weight of the finished product.
Therefore preferred liquid foam-producing blends
prepared according to the present invention will comprise
about 30-60%, preferably about 40-55~ by weight of a basic
surfactant comprising a diethanol amine salt of a fatty alco-
hol(ethylenoxy)sulfate and a diethanolamide of a fatty acid;
about 30-60~, preferably about ~0-55% of an acidic surfactant
com~rising a fatty aleohol (polyethylenoxy)acetic acid, about
1-10~ fragrance and about 1-10% propylene glycol, preferably
about 2-5%.
The liquid foamable blends are generally prepared
by mixing together the surfactants under ambient conditions,
followed by room temperature addition of the fragrance and
the propylene glycol. The resultant blend is mixed until
homogeneous and then filled into soft gelatin capsules in a
suitable cosmetic unit dose size, e.g. 3000-4000 mg, via a
rotary die encapsulation machine or similar encapsulating
device.
~he invention will be further described by refer-
ence to the following detailed example.
EXAMPLE
Lauramide DEA (Monamid~ 716, 5.0 kg), a mixture of
DEA Laureth Sulfate and Cocamide DEA (Monamine~ 779, 3.2 kg)
:
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and Tridesceth-7-Carboxylic Acid (Sandopan~ DTC-acid, 8.2 kg)
were blended to homogeneity in a stainless steel mixing vat
equipped with mechanical stirring. Citrus-jasmine fragrance
(0.52 kg) and propylene glycol (0.5 kg) were added and the
viscous liquid stirred an additional 1.0 hour at 25C. The
mixture was filled into spherical soft gelatin (SEG 90 minim)
capsules at a dose of 3500 mg per capsule by means of a
rotary die encapsulation apparatus. The batch resulted in
about 5x103 Eilled capsules.
Preliminary stability testing indicated that the ;
filled capsules did not leak or bleed after 1-2 months at
37C. The filled capsules are expected to be indefinitely
stable upon storage at controlled room temperatures of 56-
86~F (15-30~C).
When three capsules were contacted with a stream of
warm (110-120~F) soft city water, the capsule shells ruptured
in less than 1 minute and the shell completely dissolved in
about 10 minutes. Foaming was evident as soon as the shell
opened and the foam layer persisted for about 30 minutes~
Therefore, the Example demonstrates the preparation
of a foaming bath oil composition which is quickly released
from the capsule upon exposure to warm water, but which does
not negatively affect capsule wall stability upon storage.
While certain representative embodiments oE the
invention have been described herein for purposes of illus-
tration, i~ will be apparent to those skilled in the art that
modifications therein may be made without departing from the
spirit and scope of the invention.
