Progesterone-releasing intrauterine devices (IUD) have been developed for the use in experimental animals, clinical study and also for release rate measurements in vitro. The device consists of a reservoir containing progesterone surrounded by a rate-limiting ethylene vinyl acetate copolymer membrane. Progesterone is dispensed in the form of a suspension in silicone oil, which serves as drug carrier.Measurement of the drug release rate of the system was carried out under sink condition. After a initial tran...