Abstract: A transdermal drug delivery system comprising(i) an occlusive, impermeable polymeric backing layer;(ii) a drug depot on one side thereof;(iii) a removable, occlusive covering layer over said drug depot; and(iv) an adhesive means by which said delivery system, absent said removable covering layer may be affixed to an intended patient;said drug depot containing a drug formulation comprising a transdermally administrable pharmaceutically acceptable pharmaceutically active agent or a precursor thereof, water and lower alkanol; said active agent or precursor thereof being present in a pharmaceutically effective amount; said lower alkanol and said water being present in a volume:volume ratio of from 30:70 up to less than 95:5 such that said lower alkanol, water and drug are delivered to a patient's skin, which patient has applied said system absent said removable covering layer to said patient's skin, in amounts that said drug is delivered in a transdermally administrable efficacious amount, said water has an activ

Abstract: Compositions of zwitterionic drugs for transdermal administration and methods of administering zwitterions transdermally are disclosed. The compositions comprise a zwitterionic drug in a salt form and a solvent therefor.

Abstract: The invention relates to the art of transdermal administration of drug substances, particularly those drug substances having a greater solubility in ethanol than in water and those drug substances having cationic or anionic substituent groups. It is especially useful for the administration of nitroglycerin.