n alkylazacyclopentan 2 one suitable acid halide forming agents include phosphorous trichloride phosphorous tribromide thionyl chloride etc the acid halide is formed at room temperature and then the reaction temperature is raised to 70 u00b0 90 u00b0 c one of the alkyl groups on the amino nitrogen of the parent acid is eliminated as alkyl halide if the alkyl groups on the amino nitrogen are different the smaller of the two alkyl groups is eliminated preferentially this method is described below str7 the amount of 1 substituted azacycloalkan 2 one which may be used in the present invention is an effective non toxic amount for enhancing percutaneous absorption generally this amount ranges between about 0 01 to about 5 and preferably about 0 1 to 2 percent by weight of the composition the subject compositions may find use with many physiologically active agents which are soluble in the vehicles disclosed fungistatic and fungicidal agents such as for example thiabendazole chloroxine amphotericin candicidin fungimycin nystatin chlordantoin clotrimazole ethonam nitrate miconazole nitrate pyrrolnitrin salicylic acid fezatione ticlatone tolnaftate triacetin and zinc and sodium pyrithione may be dissolved in the vehicles described herein and topically applied to affected areas of the skin for example fungistatic or fungicidal agents so applied are carried through the stratum corneum and thereby successfully treat fungus caused skin problems these agents thus applied not only penetrate more quickly than when applied in the vehicles of the prior art but additionally enter the animal tissue in high concentrations and are retained for substantially longer time periods whereby a far more successful treatment is effected for example the subject composition may also be employed in the treatment of fungus infections on the skin caused by candida and dermatophytes which cause athletes.