| PATENT ASSIGNEE'S COUNTRY | USA |
| PATENT NUMBER | This data is not available for free |
| PATENT GRANT DATE | 07.11.2000 |
| PATENT TITLE |
Body powder composition |
| PATENT ABSTRACT |
A body powder composition containing croscarmellose sodium in effective moisture absorbent amounts and a powder diluent such as talc or topical starch. The composition may contain other constituents normally utilized in powders intended for topical application to the skin. |
| PATENT INVENTORS | This data is not available for free |
| PATENT ASSIGNEE | This data is not available for free |
| PATENT FILE DATE | June 23, 1999 |
| PATENT CLAIMS |
What is claimed is: 1. A body powder composition comprising: croscarmellose sodium in an amount sufficient to provide effective moisture absorbency upon topical application; and a powder diluent selected from the group consisting essentially of talc, topical starch, and mixtures thereof. 2. The composition according to claim 1, wherein said composition contains at least about 2 wt. % of croscarmellose sodium based on the total weight of said body powder composition. 3. The composition according to claim 1, wherein said composition contains no more than about 20 wt. % croscarmellose sodium based on the total weight of said body powder composition. 4. The composition according to claim 1, wherein said powder diluent is cosmetic grade talc or pharmaceutical grade talc. 5. The composition according to claim 1, wherein said powder diluent is a starch selected from the group consisting of corn starch, rice starch, potato starch, sago starch, tapioca starch, modified starch, and mixtures thereof. 6. The composition according to claim 1, further comprising at least one constituent selected from the group consisting of flow agents, medicaments, perfumes, deodorants, disinfectants, antifungal agents, skin protectants, antibacterial agents, anti-caking agents, colonizing agents, stabilizers, surfactants, antiperspirants, mildew-proofing agents, emollients, alcohols, binders, extenders, fillers, antioxidants, ultraviolet absorbers, and mixtures thereof. 7. The composition according to claim 6, wherein said composition contains no more than about 25 wt. % of said at least one constituent based on the total weight of said body powder composition. 8. A method for controlling body moisture comprising: topically applying a body powder composition, wherein said body powder composition comprises croscarmellose sodium in an amount sufficient to provide effective moisture absorbency and a powder diluent selected from the group consisting essentially of talc, topical starch, and mixtures thereof. 9. The method according to claim 8, wherein from about 2 wt. % to about 20 wt. % croscarmellose sodium is present in said body powder composition. 10. A body powder composition comprising: (a) croscarmellose sodium in an amount from about 2 to 20% based on the total weight of said body powder composition to provide effective moisture absorbency and acceptable skin feel without formation of paste or gum residue upon topical application; and (b) a powder diluent selected from the group consisting essentially of talc, topical starch, and mixtures therefore. -------------------------------------------------------------------------------- |
| PATENT DESCRIPTION |
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to powder compositions for use in human skin care. In particular, the present invention relates to a moisture-absorbing powder composition suitable for topical application to the skin comprising croscarmellose sodium. 2. Background A number of materials, and for example, talc and topical starch, have long been used in pharmaceutical and cosmetic preparations as protective agents on skin areas exposed to excessive moisture or perspiration. Powder compositions containing talc and topical starch are used for absorbing moisture resulting from the action of the sebaceous and sweat glands. Body powders are frequently used on infants to help prevent diaper rash and otherwise help maintain dryness. Powders are also used in foot care, feminine hygiene, antiperspirants and general cosmetic products. Powders have also been incorporated into creams, ointments, solid sticks or compacts. Talc is widely employed in skin care compositions, including powder compositions, because of its water repellent action, emollience and slip characteristics which lubricate skin surfaces. Its emollience and slip properties give talc its superior "skin feel" properties. Thus, talc is used in the formulation of cosmetics and as a powder for treating tender skin to prevent chafing and other irritation such as would occur from diapers or wet clothing. However, its ability to absorb aqueous fluids is quite limited. Compared to topical starch, which can absorb up to about 25 wt. % of aqueous fluids, talc has insignificant fluid-absorption capacity. The advantages of combining the absorptive action of topical starch with the emollience and lubricity of talc or other skin protectant agents have been previously recognized. By way of example, Harvey (U.S. Pat. No. 4,913,896) discloses a powder that contains talc (65-80%) and starch (20-30%) together with antibacterial and/or antifungal agents. Whistler (U.S. Pat. No. 5,453,281) substitutes small granule starch for binder excipients in pills or cosmetic and/or dusting powder compositions. However, the total absorptivity (i.e., fluid-absorption capacity) of the composition is generally unsatisfactory unless substantial amounts of starch are employed. However, if the composition contains a high proportion of starch to maintain the desired absorptivity, then the beneficial attributes provided by the other agents in the composition, such as skin feel in the case of talc, are compromised. Attempts have been made to improve the moisture absorbency properties of compositions containing talc and topical starch. For example, pregelatinized starch has been added as a minor component to talc or starch (Ashton et al., U.S. Pat. Nos. 4,485,092 and 4,568,539; Harvey, U.S. Pat. No. 4,913,896) for the purpose of increasing moisture absorption. However, pregelatinized starch hydrates in aqueous fluids and forms a paste, thereby exhibiting a gummy character which limits the desirability of this agent for skin care formulations. Furthermore, the equilibrium moisture content (or absorptivity) of pregelatinized starch at 25.degree. C. and 100% relative humidity is only about 40% greater than that of topical starch, which further limits the utility of this material. Various other ingredients, including surfactants, humectants, cellulose, various polymers and the like, have been incorporated into powder compositions for the purpose of improving their skin feel. See, for example, Nichols (U.S. Pat. No. 5,209,932); Kurisaki et al. (U.S. Pat. No. 5,024,831); and Pugh et al. (U.S. Pat. No. 4,954,334). Cellulose does not aggregate on the skin thus providing a loose sensation to the user. Furthermore, cellulose absorbs residual moisture present on the surface of the skin, resulting in an overly dry sensation to the user. Swelling and shrinking of cellulose occurs due to excess or low content of moisture in the air, respectively. Such moisture sensitivity causes cracking during or after shaping. Sodium carboxymethyl cellulose is used in a number of compositions, including a topical detergent (Birtwistle et al., U.S. Pat. No. 5,180,579), a deodorant/antiperspirant (Faryniarz et al., U.S. Pat. No. 5,135,747), dispersible tablets (Milovac et al., U.S. Pat. No. 5,047,247) and a cosmetic base (Goode et al., U.S. Pat. No. 4,946,832). Moffett (U.S. Pat. No. 3,624,200) uses talc and starch as carriers in a composition for controlling perspiration odors on human skin. Synthetic resins have also been used; however, these tend to excessively agglomerate due to their capacity to accumulate triboelectric charge. Such agglomeration causes the powder to stand out after application to the skin. The term "stand out" refers to the appearance of a powder composition after application to the skin. A composition that "stands out" is readily apparent to visual inspection: the composition may cover the skin surface so that powder-coated areas are distinguishable from non-coated areas. Others have designed microporous cellulosic powders specifically to enhance moisture absorption in skin preparations (Nichols, U.S. Pat. No. 5,209,932). The disadvantage of such systems is that they are not usually readily available and many lack a history of safe use in humans. Callingham (U.S. Pat. No. 4,650,670) discloses powder compositions containing certain non-cellulosic polysaccharides, including chemically modified starches and cross-linked polyvinylpyrrolidone, in order to obtain increased moisture absorbency. In particular, the non-cellulosic polysaccharides are said to be capable of absorbing an amount of moisture at least equal to their own weight. Despite the wide variety of known body powder compositions, there is a need for a moisture-absorbing composition that overcomes the difficulties inherent in the prior art (poor skin feel, caking, agglomeration, and the like). An ideal composition for topical use should be made of safe, readily available materials, be able to disperse easily onto the skin, carry a high payload of active ingredients, have acceptable tactile properties, and be capable of absorbing a large quantity of moisture without caking or standing out on the skin. "Super disintegrants" is a term used in the pharmaceutical industry to describe a class of readily available materials, which are widely employed in pharmaceutical dosage forms, principally in ingestible tablets and capsules. The function of these compounds is to facilitate the break-up of tablets and capsules after ingestion. Croscarmellose sodium, starch sodium glycolate and crospovidone are three common super disintegrants. (Remington: The Science and Practice of Pharmacy, 19th ed., Mack Publishing Co., vol. II, p. 1619 (1995)). Starch sodium glycolate is an insoluble low substituted carboxymethyl ether of poly-alpha-glucopyranose obtained by treatment of potato starch. Crospovidone is an insoluble cross-linked polyvinylpyrrolidone. SUMMARY OF THE INVENTION According to its major aspects and broadly stated, the present invention is a body powder composition containing croscarmellose sodium in effective moisture absorbent amounts and a powder diluent, such as talc and/or topical starch. The composition may also contain other constituents that are utilized in powders intended for topical application to the skin. Other features and advantages of the present invention will be apparent to those skilled in the art from a careful reading of the Detailed Description below. DETAILED DESCRIPTION A body powder composition according to the present invention contains croscarmellose sodium and a powder diluent such as talc and/or topical starch. The composition may also contain other constituents normally utilized in powders intended for topical application to the skin. As used herein, the terms "powder composition", "body powder composition" and "body powder" refer to a powder in a loose state or a pressed state, typically prepared by mixing a powder composed of a main constituent such as talc and/or topical starch with other constituents such as pigments, binders, perfumes, deodorants, and so forth. Any suitable powder diluent may be employed in the powder compositions of the present invention. Such diluents include, without limitation, talc, starch, metal stearates, alkali or alkaline earth carbonates, alkali or alkaline earth bicarbonates, titania, zinc oxide, clays such as kaolin and mixtures thereof. The term "talc" refers to a hydrated magnesium silicate widely used in body powder compositions. The terms "starch" and "topical starch" refer to any one of a group of carbohydrates or polysaccharides of the general composition (C.sub.6 H.sub.10 O.sub.5).sub.n, occurring as organized or structural granules of varying size and markings in many plant cells. Unless otherwise indicated, all ingredient weight % are based on the total weight of the powder composition. Starches suitable for use in the present invention include, without limitation, cornstarch, potato starch, sago starch, rice starch, tapioca starch, and mixtures thereof; however, cornstarch is preferred since it has skin affinity, uniform natural globular particle dimensionality and purity, as well as ready availability. To ensure an acceptable skin feel, the composition of the present invention preferably contains approximately 55 wt. %-98 wt. % of a powder diluent such as talc, more preferably approximately 80 wt. %-98 wt. % of the diluent, although greater or smaller amounts can be utilized. If greater amounts of the diluent are used, the resulting composition may not be capable of moisture absorption to the extent necessary to provide protection against wetness and irritation of the skin. Croscarmellose sodium is an internally cross-linked form of sodium carboxymethyl cellulose, wherein cross-linking is achieved by lowering the pH during manufacture and heating. Croscarmellose sodium is fibrous in nature with a particle size of 90% .ltoreq.44.5 .mu.m and is insoluble in water. Its fibrous cross-linked structure ensures that, when water is absorbed, the integrity of the individual particles is maintained and a paste or gum does not form. Without internal cross-linking, sodium carboxymethyl cellulose forms a pasty gum on exposure to moisture, which has an unacceptable cosmetic feel. In general, croscarmellose sodium is utilized in amounts sufficient to provide enhanced moisture absorbency upon topical application. For this and other purposes, croscarmellose sodium is preferably employed in amounts ranging from about 2 wt. % to about 20 wt. % of the total composition, more preferably from about 5 wt. % to about 20 wt. %. Amounts outside these ranges may also be utilized depending upon the desired absorbency. Importantly, improvement of water absorbency is markedly limited for compositions containing less than approximately 2 wt. % croscarmellose sodium. Compositions containing more than about 20 wt. % croscarmellose sodium tend to assume more of the skin feel (i.e., tactile sensation) of croscarmellose sodium rather than the more acceptable skin feel of the powder diluent (talc, starch). Furthermore, at concentrations exceeding approximately 20 wt. % of the total composition, water-swollen croscarmellose sodium becomes more apparent on moist skin, rendering appearance of the applied composition less acceptable. Compositions with more than about 40 wt. % croscarmellose sodium generally exhibit a skin feel and appearance that is unacceptable to users. For best results, sufficient croscarmellose sodium is present in the composition to absorb at least 2.5% by weight based on the total weight of the applied composition, and, more preferably, to absorb at least 20% by weight of moisture based on the total weight of the applied composition. Other constituents normally found in body powder compositions can be added to the croscarmellose sodium-powder diluent mixture, if desired. Such constituents include, but are not limited to, flow agents, medicaments, perfumes, deodorants, disinfectants, antifungal agents, skin protectants, antibacterial agents, anti-caking agents, colorizing agents, stabilizers, antiperspirants, emollients, binders, fillers, extenders, and mixtures and dilutions thereof. Preferably, such additives are present in an amount no greater than approximately 5 wt. % of the composition. However, depending on factors such as the selection of additive(s) and the intended use of the composition, greater amounts up to about 25 wt. % of the total composition may be useful. By way of example, a composition according to the invention may contain up approximately 25 wt. % of an antifungal agent. The constituents used in formulating the composition are preferably of a grade suitable for use in cosmetics; that is, cosmetic grade and/or pharmaceutical grade. The resulting compositions can be used directly in powder form or compacted into cakes. The compositions of the present invention can be prepared by any suitable technique, including mixing and blending procedures known to those skilled in the art. The powder constituents of the composition are typically mixed together, followed by the addition of liquid components (if present) through a liquid addition bar, spray device, or other suitable apparatus. The following non-limiting examples further illustrate the present invention. |
| PATENT EXAMPLES | This data is not available for free |
| PATENT PHOTOCOPY | Available on request |
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