Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Biocides; animal or insect repellents or attractants
Patent
1995-03-07
1998-01-27
Levy, Neil S.
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Biocides; animal or insect repellents or attractants
424405, 424417, 424420, 424421, 514401, A01N 2526
Patent
active
057119546
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND
Imidazole compounds make up an important class of antifungal compounds used to treat yeast and fungal infections. Talc has a history of consumer acceptance and is used to provide a dry and smooth feel to topical powder formulations. Talc-based powder formulations of certain imidazole compounds (ie. clotrimazole) were found to show significant degradation of the active ingredient during storage under accelerated shelf-life conditions. Deteriorating stability is important to consumers since such drugs may deliver a weaker dose than was prescribed (Jane E. Brody, The New York Times, Wednesday, Nov. 27, 1991--Personal Health: How old is that drug in your medicine cabinet?). European Patent application 0 064 283 A2 teaches that talc compositions containing sulfur-containing imidazole antimicrobial compounds can be stabilized by adding a stabilizing amount of a basic metal salt of an inorganic or organic acid. However, the results of our study indicate that the addition of hydrophilic, or water loving compounds, such as basic metal salts to talc mixtures containing non-sulfur containing imidazole compounds such as clotrimazole, did little to control its decomposition. Accordingly, a different approach was needed to improve the stabilization of clotrimazole and other non-sulfur containing imidazole compounds.
SUMMARY OF THE INVENTION
We have discovered that the stability of imidazole antifungal compounds in powder compositions containing talc can be substantially enhanced by providing to the talc a hydrophobic coating which is repellant to water.
Accordingly, the present invention is directed towards a stable powder composition comprising:
a) an effective amount of an imidazole antifungal compound selected from clotrimazole, miconazole, terconazole, econazole, isoconazole, tioconazole, sulconazole, butoconazole, oxiconazole, bifonazole, fenticonazole, omoconazole, parconazole, ketoconazole, metronidazole, itraconazole or mixtures thereof; and
b) talc coated with a hydrophobic coating in an amount from 0.5 to 5% by weight of the powder composition.
Preferably the hydrophobic coating is wax, tetrafluorethylene fluorocarbon polymers, silicone or mixtures thereof.
The present invention is also directed toward a method for stabilizing an imidazole antifungal compound in a talc composition, comprising either preparing a mixture of talc coated with a hydrophobic coating in an amount from 0.5 to 5% by weight of the powder composition, with an imidazole antifungal compound, or coating talc with a hydrophobic coating in an amount from 0.5 to 5% by weight of the powder composition, followed by preparing a mixture of the imidazole antifungal compound with the coated talc.
The present invention has the advantage of providing pharmaceutical powder compositions in which the stability of the imidazole active ingredient is improved under accelerated and normal shelf-life conditions. A second advantage of the present invention is that it provides talc powders coated with a hydrophobic coating that still maintain the smooth and free flowing properties characteristic of uncoated talc.
DETAILED DESCRIPTION OF THE INVENTION
The active ingredients (ie. imidazole antifungal compounds) are known in the art, as taught in U.S. Pat. No. 5,041,278. Such compounds can be employed in the powder compositions in amounts ranging from about 5 to about 0.5 percent by weight of the powder composition, preferably from about two to about one percent by weight, more preferably about one percent. Mixtures of various imidazole antifungal compounds can be employed, generally in ratios ranging from four to one parts of a first imidazole antifungal compound (ie. clotrimazole) to one part of a second imidazole antifungal compound (ie. miconazole), generally in about equal parts.
The term hydrophobic refers to the property of a substance that, upon its coating of uncoated talc, causes the surface of the coated talc to become substantially repellant to water.
Talc, also known as talcum, soapstone, steatite or french chalk, is a grayish-white,
REFERENCES:
patent: 3660577 (1972-05-01), Buchel et al.
patent: 4457938 (1984-07-01), von Bittera et al.
patent: 5043155 (1991-08-01), Pukhalski et al.
patent: 5262150 (1993-11-01), Laugier et al.
Derwent 82-69438E, Jul. 1982, Abstract for Japan 57112315 A, below.
PDR-Mycelex p. 1410 Tablets of Clotrimazole, 1985.
Article from the New York Times, Wednesday, Nov. 27, 1991, "Personal Health-How old is that drug in your medicine cabinet?" by Jane E. Brody.
Product Description (two pages) and Material Safety Data Sheet (6 pages) for Supra-A SMM talc, Cyprus Industrial Minerals Company, Englewood, Colorado, Jan. 1992.
Beer Don C.
Surpuriya Vijay B.
Levy Neil S.
Majka Joseph T.
Schering-Plough Healthcare Products Inc.
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