Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Having -c- – wherein x is chalcogen – bonded directly to...
Reexamination Certificate
1998-10-30
2001-02-27
Jarvis, William R. A. (Department: 1614)
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Having -c-, wherein x is chalcogen, bonded directly to...
C424S060000
Reexamination Certificate
active
06194452
ABSTRACT:
TECHNICAL FIELD
This invention relates to non-irritating, stable pharmaceutical compositions including a solution of at least one pharmaceutically acceptable silicone or oil component, and a source of pharmaceutically acceptable ascorbic acid. The invention also relates to a method for treating skin damaged by free radicals which comprises administering the above pharmaceutical composition in a therapeutically effective amount sufficient to treat and/or prevent free radical damage to skin.
BACKGROUND OF THE INVENTION
Ascorbic acid, also known as vitamin C, is an essential vitamin in the human body, which cannot synthesize vitamin C on its own. Although widely recognized for its role in the human immune system, ascorbic acid is also essential to other functions, such as the synthesis of collagen. Ascorbic acid's benefits are largely attributable to its ability to act as a reducing agent. Thus, ascorbic acid is able to boost the immune system by scavenging harmful free radicals, which are highly reactive molecular fragments having one or more unpaired electrons. [N. Sax & R. Lewis Sr.,
Hawley's Condensed Chemical Dictionary,
11th ed. Van Nostrand Reinhold 1987]. These free radicals are typically generated by the production or transfer of energy; thus, organs that use, or are exposed to, a great deal of energy, such as the brain and skin, generate numerous free radicals. For example, the transfer of energy from ultraviolet light to the skin generates free radicals such as singlet oxygen, superoxide anions, and hydroxyl radicals. [U.S. Pat. No. 5,574,063, Col. 1, lines 33-46]. If unchecked, these free radicals steal ions from other molecules, thereby destroying cells and tissues and causing chain reactions that oxidize lipids, DNA and enzymes. This often results in physical manifestations, such as sunburn and premature aging. [Id. at Col. 1, lines 40-50]. At high concentrations, ascorbic acid can protect the body against free radicals by donating ions to the free radicals, thereby neutralizing them. Moreover, ascorbic acid can help regenerate the reduced form of Vitamin E, &agr;-tocopherol, thereby rejuvenating another one of the body's major antioxidants. [H. Padh,
Vitamin C: Newer Insights into its Biochemical Functions
, Nutr. Rev. 49:65-70 (1991)].
Additionally, ascorbic acid acts as an enzyme or coenzyme in several of the body's internal chemical processes by reducing various chemical components in the process. In particular, ascorbic acid is essential to the formation of collagen, the key structural component of the extracellular network that gives strength and resilience to bodily tissues. Collagen consists of three helices spiraled around each other and bound together by hydrogen bonds, which individually are weak but collectively impart a structural strength greater than steel upon the collagen. The hydrogen bonds are catalyzed through the action of two enzymes, hydroxylase and lysyl oxidase, which are activated by ascorbic acid. Without ascorbic acid, the hydrogen bonds will not form and the collagen will fall apart, which results in a deterioration of the structural fabric of the skin, wrinkles, and in extreme cases resulting in scurvy. Ascorbic acid is not only essential to the body's production of collagen, but in the production of epinephrin, bile acid and steroids as well. [Murray et al.,
Harper's Biochemistry Twenty
-
Fourth Edition
, Appleton & Lange, pgs. 612-613. (1996)].
Unfortunately, the same attributes that make ascorbic acid vital to the human body also make it susceptible to rapid degradation, thereby making it difficult to formulate stable pharmaceutical compositions with therapeutically effective amounts of ascorbic acid. The rapid degradation of ascorbic acid is largely due to: stereochemical strains created by polar repulsive forces, oxidative degradation due to the propensity of ascorbate anions to act as a reductant, and degradation due to bulk water attack. [U.S. Pat. No. 5,140,043, Col. 2, lines 24-47].
Previously, efforts were made to overcome these difficulties by using low weight ascorbic acid, nonaqueous solvents, or derivatives of ascorbic acid. All of these methods limit the bioavailability of ascorbic acid and therefore limit the effectiveness of the formulation.
In particular, U.S. Pat. No. 5,140,043 discloses allegedly stable ascorbic acid compositions. These compositions consist of aqueous solutions containing a concentration of L-ascorbic acid above 1% W/V and having a pH below 3.5. The acidic pH of the topical application could irritate the user's skin, making the application less desirable.
Thus, a need exists for non-irritating, stable pharmaceutical compositions of ascorbic acid, which may also be used for the prevention or treatment of skin damage caused by the harmful effects of free radicals.
SUMMARY OF THE INVENTION
The present invention relates to a non-irritating, stable pharmaceutical composition which includes a solution of at least one pharmaceutically acceptable silicone component including one or more silicones or oils, and a source of pharmaceutically acceptable ascorbic acid, wherein the solution is present in an amount sufficient to inhibit degradation of the ascorbic acid while facilitating the prevention or treatment of skin damage.
In one embodiment, the silicone component includes a silicone having a general formula of [(CH
3
)
2
SiO]
x
, wherein x is an integer from about 3 to 12. In an alternate embodiment, the silicone component includes a silicone having a general formula of (CH
3
)
3
SiO{(CH
3
)
2
SiO}
y
Si(CH
3
)
3
, wherein y is an integer from about 0 to 10. In a preferred embodiment the silicone component is selected from the group of oil, cyclomethicone, dimethicone, and a mixture thereof. The solution is present in about 5 to 90 weight percent of the pharmaceutical composition.
In another embodiment, the silicone component includes an emulsifier of at least one silicone copolyol. Preferably, the emulsifier is cyclomethicone copolyol. Furthermore, the emulsifier is present in about 2 to 10 weight percent of the pharmaceutical composition.
In yet another embodiment, the source of ascorbic acid is a pharmaceutical ascorbic salt or ester of ascorbic acid. Preferably, the source of ascorbic acid is L-ascorbic acid. The source of ascorbic acid is present in about 1 to 60 weight percent of the pharmaceutical composition. In a preferred embodiment, the ascorbic acid is present in about 5 to 25 weight percent of the pharmaceutical composition.
In another embodiment, the pharmaceutical composition further includes an aqueous carrier. In a preferred embodiment, the aqueous carrier is present in about 25 to 50 percent of the pharmaceutical composition. In another preferred embodiment, the substantially all of the source of ascorbic acid is dispersed within the aqueous carrier. In another preferred embodiment, the pharmaceutical composition further includes at least one of a glucosamine, an amino acid, or a mixture thereof, dispersed within the aqueous carrier.
In a preferred embodiment, the pharmaceutical composition also includes an ingredient complex of at least one of a vitamin B
12
source, a carotenoid, a vitamin A source, and a pilewort extract. Preferably, the vitamin B
12
source is cyanocobalamin, the carotenoid is beta carotene, and the vitamin A source is retinyl palmitate. In another embodiment, the vitamin B
12
source is present in about 0.0001 to 0.1 weight percent, the carotenoid is present in about 0.01 to 5 weight percent, the vitamin A source is present in about 0.01 to 5 weight percent, and the pilewort extract is present in about 0.01 to 3 weight percent of the pharmaceutical composition.
Alternatively, the pharmaceutical composition may also include at least one of a vitamin source, antioxidant, skin conditioner, cosmetic additives, and emulsion modifiers. In a preferred embodiment, the vitamin source is a vitamin E source, the antioxidant is a catechin-based preparation, and
Jarvis William R. A.
Kim Vickie
Pennie & Edmonds LLP
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