Patch and method for producing same

Method for producing a patch comprising a backing layer and adhesive agent layer disposed on at least one surface of the backing layer, the method comprising: a step A of obtaining a composition adhesive agent layer comprising: at least one selected from the group consisting of oxybutynin and a pharmaceutically acceptable salt thereof as a drug, a polymer based on acrylic material and a rubber-based agent adhesive base, liquid paraffin, an organic acid polymer, and an alicyclic saturated hydrocarbon resin as a tackifier; a step B of heating the composition of adhesive agent layer at a temperature in a range from the melting point (° C) of the drug to a temperature higher than the melting point at 10 ° C for 2 to 24 hours; and a step C of cooling the composition of adhesive agent layer heated to a temperature lower than the melting point of the drug at an average rate of temperature drop of 1 to 20 / hour, thereby obtaining the adhesive agent layer that It comprising the drug at a supersaturated concentration in dissolved form, wherein the content of oxybutynin and pharmaceutically acceptable salt thereof in the composition of adhesive agent layer in terms of free oxybutynin is an amount which results in from 10 to 50 mass% in the layer obtained adhesive agent, the composition of adhesive agent layer comprises based acrylic polymer-based rubber at a mass ratio (mass of polymer based on acrylic polymer: polymer mass based rubber) of 1: 4 to 1:19, the content of the acrylic based polymer material composition layer of adhesive agent is an amount which co mo result of 0.5 to 10 mass% in the obtained adhesive agent layer, the polymer content in the rubber-based composition layer of adhesive agent is an amount which results in from 5 to 40 mass% in the layer obtained adhesive agent, organic acid content in the composition of adhesive agent layer is an amount which results in from 0.01 to 20 mass% in the obtained adhesive agent layer, the content of saturated hydrocarbon resin alicyclic in the composition of adhesive agent layer is an amount which results in from 10 to 60 mass% in the adhesive agent layer obtained, the mass ratio of oxybutynin and pharmaceutically acceptable salt thereof with respect to the liquid paraffin (mass in terms of free oxybutynin: mass of liquid paraffin) is 0.5: 1 to 1.2: 1 in the composition of adhesive agent layer, and the mass ratio of the total mass of the polymer based on acrylic and po limero based rubber to the mass of the alicyclic saturated hydrocarbon resin in the composition of adhesive agent layer is 1: 1 to 1: 3.