Patent ID: 8173156

Claim:
A method of avoiding crystallization of an anti-inflammatory medicament in an anti-inflammatory-containing plaster having adhesion to skin, comprising: providing a plaster consisting essentially of 5-40% by mass of a styrene-isoprene-styrene block copolymer, 1-25% by mass of a high molecular weight polyisobutylene having an average molecular weight of 50,000-200,000, 0.5-24% by mass of a low molecular weight polyisobutylene having an average molecular weight of 5,000-15,000, 3-50% by mass of a tackifier, 20-70% by mass of a plasticizer, 0.01-7% by mass of a dispersant selected from the group consisting of metal salts of fatty acid and aluminum hydroxide, the dispersant enhancing dispersibility of the styrene-isoprene-styrene block copolymer and the high molecular weight and low molecular weight-polyisobutylenes, and 0.1-8% by mass of an anti-inflammatory comprising a carboxyl group or a salt thereof as the anti-inflammatory medicament; and storing the plaster, wherein the anti-inflammatory-containing plaster does not contain L-menthol, and when the plaster is stored, the anti-inflammatory comprising a carboxyl group or a salt thereof does not undergo esterification.