A method for preparing a thermoplastic elastomer is disclosed, said method comprising mixing. The liquid container contains a dispersion medium and settleable particles. 5 mass %-30 mass % of one or two pharmaceutically active ingredient. At least one of the electrodes has a thin film electrolyte, a catalyst and an electron conducting substance, thereby suppressing the elution of the electrolyte from the catalyst layer in an electrode part and the accompanying voltage drop. The first current generator comprises an element, the resistance of which depends on the manufacturing process. The condition of each vehicle is thus managed.