this invention provides compositions comprising a physiologically - active agent and a compound having the structural formula ## str1 ## wherein x may represent sulfur or two hydrogen atoms ; r &# 39 ; is h or a lower alkyl group having 1 - 4 carbon atoms ; m is 2 - 6 ; n is 0 - 18 and r is -- ch 3 , ## str2 ## wherein r &# 34 ; is h or halogen , in an amount effective to enhance the penetration of the physiologically - active agent through the skin or other membrane of the body of an animal .