Drug – bio-affecting and body treating compositions – Anti-perspirants or perspiration deodorants
Reexamination Certificate
2000-06-02
2002-03-26
Dees, Jose′ G. (Department: 1616)
Drug, bio-affecting and body treating compositions
Anti-perspirants or perspiration deodorants
C424S401000, C424S066000, C424S067000, C424S068000
Reexamination Certificate
active
06361765
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to cosmetic compositions containing a thickened or structured liquid and in particular to such compositions containing an antiperspirant and/or deodorant active.
BACKGROUND AND PRIOR ART
Topically applied antiperspirant compositions are in widespread use throughout much of the world, in order to enable their users to avoid or minimise visible wet patches on their skin, especially in axillary regions. Antiperspirant formulations have been applied using a range of different applicators, including aerosols, roll-ons, pump sprays, sticks and mushroom applicators, in accordance with the individual preferences of consumers. In some parts of the world, sticks are especially popular. The term stick traditionally indicates a bar of solid material which was usually housed within a dispensing container and which retains its integrity whilst being applied, ie a firm stick. When a portion of a firm stick is drawn across the skin surface, a film of the stick composition is transferred onto the skin surface. Although the stick has the appearance of a solid article, the material forming the stick usually comprises a structured liquid phase such that a film of the material is readily transferred onto another surface upon contact under pressure.
More recently, the term has been applied to soft solids, which have an apparent solid form during storage, but which flow under mild pressure or shear, so that in use they can be extruded through an aperture or apertures onto a dispensing surface. Soft solids retain their shape for at least 30 seconds after extrusion under such non-shear/low stress conditions from a container, but if subjected to high shear or stress, their structure is destroyed and no more than a minor fraction of the structure can be reformed within a period of about 24 hours when the shear/stress is removed.
There are typically three classes of antiperspirant sticks, namely suspension sticks, emulsion sticks and solution sticks. Suspension sticks contain a particulate antiperspirant active material suspended in a structured carrier. Emulsion sticks normally comprise an emulsion of an oil phase and a hydrophilic phase containing the antiperspirant active in solution, the continuous phase being structured. In some emulsion sticks, the continuous phase is an oil phase. In solution sticks, the antiperspirant is typically dissolved in the liquid carrier phase which is structured. The liquid phase in a solution stick can comprise water and/or a water-miscible organic solvent. The three categories can be applied to sticks of both firm and soft solids compositions.
Conventionally, many sticks have been structured using naturally occurring or synthetic waxes, of which typical examples include stearyl alcohol, and hydrocarbon waxes or silicone waxes. waxes are widely available, and by suitable selection of the waxes themselves and their concentrations in the formulation can effectively obtain either a soft solid or a firm solid. Thus, for example, wax-structured sticks are described in an article in Cosmetics and Toiletries, 1990, vol. 105, p75-78. Wax-thickened creams are described in U.S. Pat. No. 5,102,656 (Kasat.)
However, and although the disadvantage is not mentioned in either of the above-identified references, it has been observed that wax structured compositions tend to leave visible white deposits on application to human skin, and the deposits can also be transferred onto clothing by physical contact with the skin. A significant, and possibly growing, proportion of consumers of antiperspirants have indicated displeasure at visible deposits. Accordingly, the antiperspirant industry, including the instant inventors, is devoting considerable time and resources to finding means to ameliorate or overcome the customer perception of white deposits.
Amongst the class of naturally occurring waxes which have been used or contemplated for use in thickening or structuring an oily liquid phase of an antiperspirant or deodorant composition, animal-derived waxes include beeswax, and vegetable-derived waxes include candelilla wax and carnauba wax. Each of these waxes comprises in general terms a mixture of a) esters, often including an alkyl moiety of at least 8 carbons length derivable from a fatty acid or fatty alcohol, and/or an aromatic hydrocarbon moiety, b) non-esterified fatty acids, c) non-esterified fatty alcohols, d) non-gaseous hydrocarbons and e) resins. The proportions of the wax constituents varies depending on the particular wax selected, and to a lesser extent on their geographical location where they are produced and the time of year.
Various disadvantages have been attributed to the incorporation of naturally occurring waxes, including in particular beeswaxes, such as the disadvantage of variation in properties of the waxes arising from their natural variation in constitution and also the disadvantage arising from the presence of the non-esterified acids and/or alcohols in the wax mixtures. Accordingly, in a number of disclosures, some waxes have been subjected to chemical processes to increase their esters content, prior to their incorporation in a cosmetic formulation.
For example, in U.S. Pat. No. 5,176,902, a coloured cosmetic stick is obtained by incorporating a wax which had been esterified with a C1-60 mono or polyhydric alcohol to convert all naturally present C12-60 fatty acids into their respective esters. In J Kokai 58-092605 there is described the production of a modified beeswax in which free acids are esterified. The product was stated to have excellent pigment dispersibility, e.g. in a massage cream. In EPA-319062 and U.S. Pat. No. 4,948,584, Koster Keunen describe a process for modifying beeswax by removing free acids. The resultant product has self-emulsifying characteristics. None of those publications mention the visible white residue of structured or thickened antiperspirant or deodorant compositions and in consequence give no teaching on how to ameliorate or solve the problem.
However, the principle reason for incorporating a wax in a formulation is often to structure or thicken a carrier fluid forming a firm or soft solid. It is advantageous to identify waxes which have a superior ability to structure or thicken a carrier fluid. For example, only a smaller proportion of the wax is needed to achieve a desired extent of thickening or structuring, thereby increasing the options on the producer of cosmetic compositions to vary the remaining constituents. Moreover, the inventors recognised that waxes can be now implicated in at least contributing to the visibility of deposits on skin, and so they concluded that visible deposits may be observable to a lesser extent if less wax were needed.
Cosmetic compositions thickened or structured using polysiliconyl modified beeswaxes have been described in WO 98/09609 and using hexanediol-behenyl beeswaxes in WO 98/09712. However, in the course of their present investigations, the present inventors have found that the capability of derivatives of beeswax to thicken or structure an antiperspirant or deodorant carrier fluid varies, depending on the nature of the modification. Thus, for example, polysiliconyl-modified beeswaxes and fatty acid esterification of free fatty acids in beeswaxes (as in the production of hexanediol-behenyl beeswaxes) have both been observed to produce materials having a relatively poor structuring capability. Consequently, a pre-treatment of beeswaxes does not necessarily result in the modified beeswax having an effective structuring capability.
One class of stick which has been contemplated for antiperspirant or deodorant application comprises an emulsion stick. Such sticks comprise a continuous phase in which droplets of a second liquid phase are dispersed, normally referred to as a disperse phase. The continuous phase is one of hydrophobic or aqueous, and the disperse phase constitutes the other. The antiperspirant or deodorant active is conveniently incorporated within the aqueous phase. The hydrophobic phase can be structured by incorporation o
Emslie Bruce Steven
Stoimenof Laura Dimitrova
Turner Graham Andrew
Dees Jose′ G.
George Konata M.
Stein Kevin J.
Unilever Home & Personal Care USA , division of Conopco, Inc.
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