Patent ID: 7785622

Claim:
An adhesive patch for maintaining a long-term drug efficacy of fentanyl for more than 48 hours, said patch comprising a backing layer and a pressure-sensitive adhesive layer formed on one side thereof, wherein the pressure-sensitive adhesive layer consists essentially of fentanyl as an active ingredient, a pressure-sensitive adhesive base, and a tackifier resin, wherein the pressure-sensitive adhesive base comprises polyisobutylene and a styrene/isoprene/ styrene block copolymer, the proportion of the polyisobutylene in the adhesive base being 8 to 15 wt. %, and a ratio of a concentration of the polyisobutylene to that of the styrene/isoprene/styrene block copolymer being from 2:3 to 3:2, and wherein the tackifier resin is an alicyclic saturated petroleum resin and a proportion of the tackifier resin is from 40 to 50 wt. %, with the proviso that the adhesive patch does not contain sodium acetate.