由于皮质甾类制剂在某些条件下不稳定,如油膏的乳化、赋形剂中含有丙二醇、水溶液的pH值在0.5～8.0等条件下易降解,使倍他米松17位戊酸酯重排成效价下降15倍的21位戊酸酯,随着再继续水解成倍他米松醇.本文介绍以反相HPLC法在聚西托醇霜和白凡士林两种稀释剂中测定倍他米松17-戊酸酯和 Since corticosteroid preparations are unstable under certain conditions, such as oily emulsification, the excipient contains propylene glycol and the pH value of the aqueous solution is easily degraded under the conditions of 0.5 to 8.0, so that the 17-position valerate of betamethasone The 21-mercaptoethanol ester, which has been reduced by 15 times the titer, was hydrolyzed to betamethasone alcohol.This paper describes the determination of betamethasone 17 by reversed phase HPLC in two diluents, polyeto alcohol and white petrolatum - valerate and