A stable transdermal adhesive composition comprising: an adhesive comprising a washed polymerization reaction product of at least two ethylenically unsaturated monomers; and at least one pharmaceutically active compound which is susceptible to oxidative degradation; wherein the at least two ethylenically unsaturated monomers, if present in the adhesive as unreacted monomers, are present at a level of less than 200 ppm of total unreacted monomer, based upon the total weight of the adhesive, methods of making the composition, a transdermal drug delivery device using the composition, methods of making the device, and methods of delivery the pharmaceutically active compound are provided.