Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Cosmetic – antiperspirant – dentifrice
Reexamination Certificate
1998-12-15
2001-05-01
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Cosmetic, antiperspirant, dentifrice
C424S078030, C424S404000
Reexamination Certificate
active
06224886
ABSTRACT:
The present invention relates to compositions for topical application to the skin surface including the scalp, in particular to antibacterial skin wash compositions which are applied to water-wetted skin, and subsequently rinsed off with water. Specifically, the present invention relates to skin wash compositions comprising triclocarban as the active antibacterial ingredient formulated in a mild and non-irritant detergent base.
Antibacterial cleansing compositions are widely used in the health care industry, for example in hospitals, in the form of scrubs and washes. Skin cleansing compositions comprising an antibacterial agent also have utility in the domestic environment both as general cleansers and in particular for the treatment and prevention of acne, a pilosebaceous disease characterised by comedones containing sebum, protein debris and anaerobic microorganisms including
Propionibacterium acnes
(
P. acnes
). The active ingredient of products which are currently available on general sale as skin cleansers, including cleansers targeted for the treatment and prevention of acne, include for example salicylic acid, benzoyl peroxide and triclosan. Such compounds whilst conferring a beneficial effect on the skin may cause local irritation when applied to sensitive areas, in particular the face. Moreover, local irritation may be exacerbated by the carrier system in which the active ingredient is formulated. For example, skin wash compositions and in particular face wash compositions which generally include a soap-free detergent base selected for effective cleansing and foaming, may confer an irritant effect due to the use of surfactants commonly employed in such detergent systems.
European Patent Publication 0 670 158 A2 discloses an aqueous liquid composition comprising about 4 to 10 wt % of anionic surfactant about 1.5 to 5 wt % of betaine about 1.5 to 8 wt % of an alkyl polyglycoside wherein the average degree of polymerisation is from about 1.1 to 6 and the average alkyl length is from about 8 to 16 carbon atoms inclusive, and an antibacterial effective amount of an antibacterial agent or mixture of antibacterial agents, which compositions are described as being at least as mild if not actually milder than various commercial antibacterial liquid cleansing compositions on the market place. The preferred antibacterial agent is a member of the family of halogenated phenoxy diphenyl ethers, most preferably the compound 2,4,4′-trichloro-2′-hydroxyphenylether which has the generic name triclosan.
Triclocarban (3,4,4′-trichlorocarbanilide-N-(4-chloropheny-N-3,4-dichlorophenyl)urea) is an antibacterial agent with broad spectrum activity. It is effective against bacteria commonly found on the skin, including pathogenic Staphylococcus species which are resistant to many bacteriostats. It has been shown to reduce body odour by preventing growth of the causative organisms. It is non-irritant and has a high affinity for the skin which means that the bacteriostatic effect persists after application. The low mammalian toxicity of triclocarban together with its antibacterial activity have given rise to its usage as a bacteriostatic agent in bar soaps for over 35 years and more recently in liquid soap products. Triclocarban is described in the promotional materials of its commercial suppliers as having activity at low concentrations in finished products, typically in the range 0.5 to 1.5% w/w.
Triclocarban has a very low water solubility (<0.1%). This confers the advantage that once applied to the skin, it is not readily removed by rinsing. However, a problem arising from its low water solubility is that it requires addition of substantial quantities of organic solvents if a clear liquid product is to be obtained. Alternatively, it can be formulated as a suspension, the stability of which can be controlled by emulsification.
Experiments have now shown that triclocarban is highly effective against
Propionibacterium acnes
at low concentrations. The NIC value against
P. acnes
has been measured at 1.49 compared to a value of greater than 12.79 for triclosan.
It is an object of the present invention to provide a skin wash composition, preferably as a clear liquid product, containing an antibacterial agent which is effective against
P. acnes
in a detergent base which has good cleansing and foaming characteristics, which composition is mild and non-irritant to the skin. This object is achieved according to the present invention which is based on the unexpected finding that the antimicrobial agent triclocarban is effective against
P. acnes
at unusually low concentrations and can be incorporated in a mild detergent base comprising a mixture of a non-ionic alkylpolyglucoside surfactant and an amphoteric surfactant which has the desired cleansing and foaming characteristics in the absence of an anionic surfactant.
According to the present invention there is provided a skin wash composition comprising from 0.05 to 0.25% w/w of triclocarban and a detergent base consisting of a mixture of a non-ionic alkylpolyglucoside surfactant and an amphoteric surfactant in the absence of an anionic surfactant. Preferably the concentration of triclocarban in the composition will be in the range 0.075 to 0.15% w/w and more preferably 0.10% w/w. Surprisingly, it has also been found that triclocarban is more effective against
P. acnes
when the detergent base content of the composition is reduced.
As used herein, the term alkylpolyglucoside surfactant means a non-ionic surfactant derived from common natural organic monomer units as found in starch, fats and sugars, and most suitably derived from D-glucose monomer units. Alkylpolyglucosides derived from D-glucose are acetal compounds in which the alkyl residue has a carbon chain length of from 8 to 16 carbon atoms and the degree of glucosidation (or polymerisation), ie. the average number of glucose units per alkyl radical, is between 1.1 and 6. A range of suitable alkylpolyglucosides are commercially available either individually or as mixtures or blends. Compositions according to this invention will generally contain mixtures or blends of different alkylpolyglucosides. Preferred alkylpolyglucosides for use in the present invention include decyl glucoside and lauryl glucoside and mixtures thereof. Alkylpolyglucoside surfactants generally comprise up to 15% w/w of the skin wash composition, suitably from 2.0 to 10.0% w/w and preferably from 4.0 to 6.0% w/w of the composition. It will be appreciated that the amount of alkylpolyglucoside will be determined to some extent by the nature and amount of amphoteric surfactant present in the composition.
In principle, any amphoteric surfactant which is acceptable for topical application to the skin may contribute, with the alkylpolyglucoside surfactant, to the detergent base but, in view of their inherent mildness and good foaming performance, the preferred amphoteric surfactant will belong to the class of compounds known as betaines. Structurally, betaine compounds contain a carboxylate functional group and a quaternary nitrogen function separated by a methylene moiety. They include n-alkyl betaines such as cetyl betaine and behenyl betaine, and n-alkylamido betaines such as cocomidopropyl betaine. The amphoteric surfactant component of the detergent base for compositions of the present invention may be a single compound or a mixture or blend of two or more different substances. A preferred amphoteric surfactant is cocamidopropyl betaine. Amphoteric surfactants will generally comprise up to 10% w/w of the skin wash composition, suitably from 2.0 to 8.0% w/w and preferably from 2.5 to 5.0% w/w of the skin wash composition. The amount of amphoteric surfactant will to some extent be determined by the alkylpolyglucoside surfactant component of the detergent base.
Typically, the detergent base consisting of the mixture of non-ionic alkylpolyglucoside surfactant and amphoteric surfactant will constitute no more than 20% w/w of the skin wash composition. Suitably the detergent base will constitute from
Charlton Lynda Rosemary
McGillycuddy Juliet Teresa
Howard S.
Kinzig Charles M.
Nora Stein-Fernandez
Page Thurman K.
SmithKline Beecham p.l.c.
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