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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.
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Background Proliferative vitreoretinopathy(PVR) is a tissue repair prevention and treatment of PVR in clinic.Natural delayed release microballoons are therefore becoming a hot spot for its easy manipulation,large lading dose and long acting duration.Objective This study was to evaluate the effect of 5-fluorouracil natural delayed release microballoons on the prevention of PVR.Methods The lymphocytes were collected from clean pigment rabbit to prepare the 8×107/ml cell suspension with complete culture fluid.PVR models were established in 45 healthy pigment rabbits by intravitreal injection of lymphocyte suspension.The animals were randomly divided into 3 groups and 15 rabbits for each.0.1ml normal saline,10g/L or 20g/L 5-fluorouracil natural delayed release microballoons were injected into vitreous cavity respectively.PVR was graded on Fastenberg's method under the slit lamp in 1,2,4,8 weeks.The animals were sacrificed and retinas were obtained for the histopathological and ultrastructural examination in the eighth week after administration of drug.Results The numbers of eyes with different grades of PVR were significantly different among 3 groups in 1 week,2,4,8 weeks(P＜0.05).The eye numbers with PVR was significant less in 20g/L Fu group than those of 10g/L Fu group and normal saline group(P＜0.05).There was statistical difference in PVR ranking among these 3 groups in 8 weeks after injection of drug(H=46.795,P＜0.05).The morphology and ultrastructure of retinas under the light microscope and transmission electron microscope were near normal in all of the three groups.Conclusion Implantation of 5-fluorouracil natural delayed release microballoons into vitreous cavity is effective and safe in preventing PVR in experimental model,and the therapeutic effect of microballoons with 20g/L 5-Fu is better.
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<p><b>AIM</b>To investigate the effect of preparation technique on in vitro release mechanism of huperzine A-PLGA microspheres.</p><p><b>METHODS</b>Huperzine A-PLGA microspheres were prepared by two kinds of O/O emulsion solvent evaporation method (method A and B). In vitro release mechanism was explained by release profile, degradation rate and swelling rate of microspheres in vitro. The microspheres morphology and drug distribution within microspheres were observed in order to explain further the drug release mechanism.</p><p><b>RESULTS</b>The encapsulation efficiency of huperzine A microspheres prepared by method A and B was 47.60% and 83.50% respectively. Microspheres prepared by method A could sustain release for 35 days with nearly no initial burst release. The release profile fitted well to zero order equation and drug release mainly through degradation and diffusion mechanism. Huperzine A microspheres prepared by method B could sustain release for 21 days with some evidence of initial burst release. The release profile fitted well to the Higuchi equation and drug release was mainly through diffusion mechanism.</p><p><b>CONCLUSION</b>Huperzine A microspheres prepared by method A had more desirable release profile.</p>