Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Having -c- – wherein x is chalcogen – bonded directly to...
Reexamination Certificate
1999-07-23
2001-08-28
Dudash, Diana (Department: 1619)
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Having -c-, wherein x is chalcogen, bonded directly to...
C424S401000, C424S405000, C424S070220, C424S070230, C424S070240, C424S070310, C424S730000, C424S725000, C514S937000, C514S939000, C514S940000, C514S941000, C514S943000
Reexamination Certificate
active
06281236
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention is directed to oil-in-water emulsions in which allantoin has improved stability, particularly for cosmetic and over-the-counter drug applications.
Allantoin is a commonly used ingredient in cosmetic applications, particularly for skin creams, where it exerts a skin protective function. Many such cosmetic compositions are prepared as emulsions, particularly oil-in-water emulsions. One emulsifier system used with such compositions is a combination of sodium lauryl sulfate and beeswax. Although solutions of sodium lauryl sulfate are alkaline with an approximate pH of 9.5, the simultaneous use of beeswax with its organic acids produces a complex and neutralized system with a pH of about 6.8 to about 7.5. However, in such a system with a pH range of 6.8 to 7.5, allantoin degrades significantly with time in an accelerated stability test at 40° C. Because cosmetics are typically stored by users at room temperature, and room temperatures can fluctuate with climatic conditions, such a degree of instability is undesirable. Therefore, there is a need for an oil-in-water emulsified composition containing allantoin that uses the sodium lauryl sulfate-beeswax emulsion system in which the stability of allantoin is increased.
SUMMARY
An improved composition containing allantoin uses an emulsification system in which the pH is adjusted to from about 4.5 to about 5.8 with the use of a small amount of acid.
The emulsification system can include beeswax and an anionic emulsifier that is substantially hydrophilic and is soluble in water. Alternatively, the emulsification system can include a nonionic emulsifier that is an ethoxylated ether or an ethoxylated ester whose carbon chain length ranges from 8 to 22 carbon atoms.
One embodiment of a composition according to the present invention comprises:
(1) allantoin; and
(2) an emulsifier system including beeswax and an anionic emulsifier that is substantially hydrophilic and is soluble in water, the pH of the emulsion being from about 4.5 to about 5.8 after the addition of acid to bring the pH into the range.
The emulsifier can be selected from the group consisting of ammonium lauryl sulfate, sodium lauryl sulfate, sodium laureth sulfate, sodium oleyl succinate, ammonium lauryl sulfosuccinate, sodium dodecylbenzenesulfonate, ammonium laureth sulfate, and sodium lauryl sarcosinate. In one preferred embodiment, the emulsifier is sodium lauryl sulfate.
The composition can comprise at least one organic acid of from 2 to 22 carbon atoms. The organic acid can be citric acid, ascorbic acid, glycolic acid, lactic acid, benzoic acid, or salicylic acid. Alternatively, the composition can comprise at least one inorganic acid selected from the group consisting of hydrochloric acid, sulfuric acid, and phosphoric acid. The composition can comprise both organic and inorganic acids.
Another embodiment of a composition according to the present invention comprises an oil-in-water emulsion comprising:
(1) allantoin; and
(2) an emulsifier system including at least one nonionic emulsifier that is an ethoxylated ether or an ethoxylated ester whose carbon chain length ranges from 8 to 22 carbon atoms, the pH of the emulsion being from about 4.5 to about 5.8 after the addition of acid to bring the pH into the range.
The composition can further include a number of ingredients. These ingredients can include the following:
(1) an emollient component that is one or more of lanolin oil, cetyl alcohol, stearyl alcohol, cod liver oil, and butylated hydroxytoluene;
(2) herbal extracts, including one or more of St. John's wort extract, witch hazel extract, chamomile extract, and arnica extract;
(3) a preservative component that is one or more of methylparaben and propylparaben; and
(4) a solvent component that is one or more of propylene glycol, glycerol, or butylene glycol, and is preferably propylene glycol.
One preferred composition according to the present invention comprises:
(1) water;
(2) sodium lauryl sulfate;
(3) propylene glycol;
(4) tetrasodium EDTA;
(5) citric acid;
(6) lanolin oil;
(7) cetyl alcohol;
(8) stearyl alcohol;
(9) beeswax;
(10) cod liver oil;
(11) butylated hydroxytoluene;
(12) St. John's wort extract;
(13) witch hazel extract;
(14) chamomile extract;
(15) arnica extract;
(16) methylparaben;
(17) propylparaben;
(18) allantoin; and
(19) fragrance;
where the pH of the composition is from about 4.5 to about 5.8.
A more preferred composition according to the present invention comprises:
(1) from about 50% to about 90% of water;
(2) from about 0.5% to about 2.5% of 30% sodium lauryl sulfate;
(3) from about 2.0% to about 9.0% of propylene glycol;
(4) from about 0.05% to about 0.50% of tetrasodium EDTA;
(5) from about 0.05% to about 0.5% of citric acid;
(6) from about 5% to about 15% of lanolin oil;
(7) from about 3% to about 10% of cetyl alcohol;
(8) from about 1% to about 5% of stearyl alcohol;
(9) from about 0.5% to about 2.5% of beeswax;
(10) from about 1.0% to about 7.0% of cod liver oil;
(11) from about 0.1% to about 1.0% of butylated hydroxytoluene;
(12) from about 0.05% to about 0.50% of St. John's wort extract;
(13) from about 0.05% to about 0.50% of witch hazel extract;
(14) from about 0.05% to about 0.5% of chamomile extract;
(15) from about 0.05% to about 0.5% of arnica extract;
(16) from about 0.1% to about 0.5% of methylparaben;
(17) from about 0.1% to about 0.5% of propylparaben;
(18) from about 0.50% to about 2% of allantoin; and
(19) from about 0.05% to about 0.50% of fragrance;
the pH of the composition being from about 4.5 to about 5.8.
A still more preferred composition according to the present invention comprises:
(1) from about 55% to about 75% of water;
(2) from about 1.0% to about 2.5% of 30% sodium lauryl sulfate;
(3) from about 3.0% to about 6.0% of propylene glycol;
(4) from about 0.1% to about 0.3% of tetrasodium EDTA;
(5) from about 0.08% to about 0.35% of citric acid;
(6) from about 8.0% to about 12.0% of lanolin oil;
(7) from about 3.5% to about 7.5% of cetyl alcohol;
(8) from about 1.0% to about 3.0% of stearyl alcohol;
(9) from about 1.0% to about 2.5% of beeswax;
(10) from about 1.0% to about 4.0% of cod liver oil;
(11) from about 0.2% to about 0.8% of butylated hydroxytoluene;
(12) from about 0.05% to about 0.15% of St. John's wort extract;
(13) from about 0.05% to about 0.15% of witch hazel extract;
(14) from about 0.05% to about 0.15% of chamomile extract;
(15) from about 0.05% to about 0.15% of arnica extract;
(16) from about 0.15% to about 0.40% of methylparaben;
(17) from about 0.10% to about 0.30% of propylparaben;
(18) from about 0.50% to about 2.0% of allantoin; and
(19) from about 0.1% to about 0.3% of fragrance;
the composition having a pH of from about 4.5 to about 5.8.
A still more preferred composition according to the present invention comprises:
(1) about 68.68% of water;
(2) about 1.9% of 30% sodium lauryl sulfate;
(3) about 5.3% of propylene glycol;
(4) about 0.15% of tetrasodium EDTA;
(5) about 0.12% of citric acid;
(6) about 10.6% of lanolin oil;
(7) about 4.2% of cetyl alcohol;
(8) about 2.0% of stearyl alcohol;
(9) about 1.90% of beeswax;
(10) about 2.0% of cod liver oil;
(11) about 0.5% of butylated hydroxytoluene;
(12) about 0.1% of St. John's wort extract;
(13) about 0.1% of witch hazel extract;
(14) about 0.1% of chamomile extract;
(15) about 0.1% of arnica extract;
(16) about 0.3% of methylparaben;
(17) about 0.25% of propylparaben;
(18) about 1.50% of allantoin; and
(19) about 0.20% of fragrance;
the composition having a pH of from about 4.5 to about 5.8.
DESCRIPTION
An improved composition containing allantoin uses an emulsification system including either: (1) beeswax and an anionic emulsifier that is substantially hydrophilic or (2) a nonionic emulsifier that is an ethoxylated ether or an ethoxylated ester whose carbon chain length ranges from 8 to 22 carbon atoms, in which the pH is adjusted to from about 4.5 to about 5.8 with the use of a small amount of acid. As shown below in Example 4, the stability of allantoin at 40° C. is grea
Alwyn Company, Inc.
Dudash Diana
Oppenheimer Wolff & Donnelly LLP
Sharareh S
LandOfFree
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