ABSTRACT
OBJECTIVE: To prepare and in vitro evaluate the shell vaginal ring(VR)containing mifepristone. METHODS: The solid dispersion of mifepristone with PVPK30 as a carrier was prepared and characterized by the methods of differential scanning calorimetry (DSC) and X-ray diffraction analysis (XRD). The shell vaginal ring containing mifepristone was prepared by the method of mold molding process, the inner layer of vaginal ring is the blank silastic skeleton, the middle layer of vaginal ring is the part containing drug, the outermost layer is a non-active silicon rubber membrane. In vitro drug release test was conducted in a dissolution apparatus, release medium was 200 mL PBS (pH 4.0) meeting with sink conditions, and release samples were determined by the UV-vis spectrophotometry. RESULTS: The shell vaginal ring containing mifepristone had a steady drug release rate in vitro during 21 d. The daily release of mifeprisotne was about 1 mg, which sustained two weeks at least at this release rate, and the variance intra- batch was very small. CONCLUSION: The shell vaginal ring containing mifepristone exhibits the sustained and controlled release characteristics in vitro, and the preparation method is stable. The developed UV-vis method is rapid, accurate and convenient.