Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Cosmetic – antiperspirant – dentifrice
Reexamination Certificate
1999-05-03
2003-11-18
Padmanabhan, Sreeni (Department: 1619)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Cosmetic, antiperspirant, dentifrice
C514S762000, C514S865000, C514S943000
Reexamination Certificate
active
06649175
ABSTRACT:
INTRODUCTION TO THE INVENTION
The present invention pertains to compositions which protect the skin against the effects of irritants, and more particularly to compositions which can be applied to the skin for protection against contact with body fluids and wastes.
A substantial fraction of the population suffers at some time from a form of incontinence. Incontinence is normal with infants, but frequently incontinence is also the result of aging or some other uncontrolled mental or physiologic process. Absorptive pads and impervious garment liners are available to contain the excreted wastes and prevent their leakage onto clothing, furniture and the like, but many of these tend to maintain the wastes in contact with skin for prolonged periods and cause dermatolologic problems.
The skin normally is capable of maintaining adequate internal moisture to remain pliable. This condition typically requires an internal relative humidity (“RH”) at least about 60 percent. Various factors, including the presence of lipid components in the skin, work to maintain proper RH values for most aspects of normal living. However, exposure to external moisture sources can cause a depletion of skin lipids and a consequential dermatitis. This condition is aggravated when the external moisture source also contains irritating chemicals, such as are present in body wastes.
The are commercially available products for coating the skin to prevent deleterious contact with chemical substances. Such products are generally called “barrier” creams, lotions or ointments and are based on impervious substances such as petrolatum, silicone greases, heavy oils, waxes and the like. Unfortunately, these materials leave a very greasy, sticky or oily uncomfortable coating on the skin and therefore are best suited as substitutes for vinyl or rubber gloves, applied just prior to exposure to detergents, industrial chemicals, etc. For application to the pubic and perianal regions of the body, many persons would prefer a substance similar to those lotions, creams and the like normally used for the typical non-barrier skin care products; these are commonly emulsions of the oil-in-water type, since the skin absorbs these formulations more readily than it does oil-external formulations and does not acquire a greasy or oily feel after application of the product.
Accordingly, it was undertaken by the present inventors to develop an oil-in-water barrier lotion formulation which, after application to the skin, promptly feels dry, smooth and non-oily, and which effectively inhibits skin irritation from prolonged contact with body wastes or other irritants.
SUMMARY OF THE INVENTION
The invention resides in a barrier lotion comprising: about 5 to 15 percent by weight of a long-chain fatty acid; about 1 to 5 percent by weight of a long-chain fatty alcohol; about 1 to 10 percent by weight of a hydrocarbon oil; about 1 to 30 percent by weight of a silicone skin protectant; about 0.5 to about 5 percent by weight of an alkanolamine; about 0.5 to about 5 percent by weight of a humectant; about 0.5 to about 10 percent by weight of an inorganic skin protectant; about 0.5 to 15 weight percent of a preservative; and about 50 to 90 percent by weight water. A very desirable additional component is up to about 5 percent by weight of a fragrance, odor neutralizer or a mixture thereof.
DETAILED DESCRIPTION OF THE INVENTION
Throughout this specification, the term “percent” is intended to mean, unless the context clearly indicates otherwise, percentages by weight. Various formulation components are identified herein by their adopted names as given by J. M. Nikitakis et al., Eds., CTFA
International Cosmetic Ingredient Dictionary
, Fourth Ed., The Cosmetic, Toiletry and Fragrance Association, Washington, D.C., 1991. The functions performed by various components are listed by J. A. Wenninger et al., Eds., CTFA
Cosmetic Ingredient Handbook
, Second Ed., The Cosmetic, Toiletry and Fragrance Association, Washington, D.C., 1992.
The invention encompasses skin barrier lotions comprising: about 5 to 15 percent by weight of a long-chain fatty acid; about 1 to 5 percent by weight of a long-chain fatty alcohol; about 1 to 10 percent by weight of a hydrocarbon oil; about 1 to 30 percent by weight of a silicone skin protectant; about 0.5 to about 5 percent by weight of an alkanolamine; about 0.5 to about 5 percent by weight of a humectant; about 0.5 to about 10 percent by weight of an inorganic skin protectant; about 0.5 to 15 weight percent of a preservative; and about 50 to 90 percent by weight water. Optionally, there also is included up to about 5 weight percent of a fragrance odor “neutralizer” or mixtures thereof.
The long-chain fatty acid is generally a substituted or unsubstituted carboxylic acid, having carbon atoms (inclusive of the carboxy group) numbering about 12 to about 22. Of course, the acid must be chosen from those which are safe for prolonged skin contact when formulated in water-external emulsions according to the general teachings herein. The acids generally should have melting points higher than the temperature of the skin to which the barrier lotion is applied, so that the acid will be at least partially in solid form after application to the skin; the solid phase permits the acid to give a “dry” feel to the skin and facilitates the occlusive function of the acid. Preferred normal carboxylic acids for purposes of the invention include, without limitation, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid and tricosanoic acid. In general, the unsaturated acids will have melting points too low to be preferred for this invention. Concentrations of the acid are generally about 5 to 15 percent, preferably about 8 to 11 percent.
The inventors presently have a preference for stearic acid, particularly in the “triple pressed” purity grade to obtain a product having consistent properties.
An alkanolamine component is desired, as this material can react with the long chain fatty acid to form an emulsifier of the type frequently used to produce cosmetic skin creams and lotions. Several alkanolamines can be used, including ethanolamine, diethanolamine, triethanolamine, isopropanolamine, diisopropanolamine, triisopropanolamine, methylethanolamine and others. About 0.5 to 5 percent alkanolamine will be present in the formulation, preferably about 1 to 2 percent. The long chain fatty acid content should be adjusted, such that an excess of fatty acid is present over that amount which will completely react with the alkanolamine to form a salt; sufficient excess acid should be used to produce a formulation having pH values approximating that of the skin, i.e., averaging about 5 to 6. Particularly when the long chain fatty acid is stearic acid, the choice of triethanolamine is preferred, as the emulsifier salt formed from these components gives a very desirable lotion product in accordance with the invention.
A further required component is the long chain fatty alcohol, being branched or unbranched, substituted or unsubstituted, and having about 14 to about 22 carbon atoms. This component also provides an occlusive effect and, for obtaining the desired “dry” feel on the skin, should have a melting point higher than the temperature of the skin. Preferred normal alcohols include myristyl alcohol, cetyl alcohol and stearyl alcohol. The alcohol component is typically present in a barrier lotion at concentrations of about 1 to about 5 percent, and more preferably about 1 to about 4 percent.
A hydrocarbon oil or plant- or animal-derived oil is included in a formulation as a skin conditioning agent to maintain an appropriate moisture level within the skin, and may act as a humectant to assist in controlling the rate of water loss from the emulsion film as it is being applied. Mineral oil has been found preferable for this purpose, and is generally present at about 1 to about 10 percent. Preferred concentrations are about 0.5 to about 5 percent. The amount of this component should be minimized, to prevent an oily feel on the skin and to facili
Haslwanter Joseph A.
Rencher William F.
Franks Robert A.
Padmanabhan Sreeni
Schering-Plough HealthCare Products Inc.
Wells Lauren Q.
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