Evaluation of in Vitro Release Profile and Local Retention of Estradiol Vaginal Thermosensitive Gel / 中国药学杂志

ABSTRACT

OBJECTIVE: To examine the in vitro release profile and in vivo retention of estradiol vaginal thermosensitive gel (E2-VTG). METHODS: E2-VTISG was prepared by cold dissolving method.The dynamic membrane dialysis method and HPLC-fluorometric method were used to determine the in vitro release characteristic of the estradiol vaginal thermosensitive gel.CRi Maestro was applied to evaluate the retention of E2-VTG in ICR mice with IR820 as the fluorescent marker. RESULTS: Estradiol could be released slowly from the thermosensitive gel and the release profile was fitted with Higuchi equation. It was speculated that estradiol was mainly released through diffusion.NIR imaging and fluorescence quantitative analysis showed that thermosensitive gel could reside in vagina for at least 8 h. CONCLUSION: Estradiol thermosensitive gel can prolong the drug residence time in vagina and sustain the drug release rate.