Inhibitory Effect of Mifepristone-releasing Implants on Endometriosis in Rats

OBJECTIVE:To observe the efficacy of mifepristone-releasing implants for endometriosis in rats.METHODS:Mifepristone-releasing implants(one tube at 0.75,1.5,and 3.0 cm in length,or 2,3,4 tubes at 3 cm in length) were embedded subcutaneously in model rats with endometriosis.The inhibition ratio on the endometriosis was measured 3 months later and compared with the placebo control group.RESULTS:In vitro mean drug release rate of about 9 μg·d-1 was achieved for the one-tube implant at 3 cm in length for the first 15 days,but reduced to 5 μg·d-1 after 30 days and which was maintained for over 6 months.Inhibition ratios of(18.6±17.3)%,(31.5±12.7)% and(72.2±12.3)% on the growth of endometrial explants were achieved after subcutaneous implantation of mifepristone-releasing implants(1 tube at 1.5 cm or 3 cm in length or 2 tubes at 3.0 cm in length),showing significance differences as compared with control group(P0.05).CONCLUSION:It is feasible for subcutaneous mifepristone-releasing implant as extended action drugs for endometriosis.