Screening of forming prescription of Weishu in situ gel and study on its release property

OBJECTIVE To optimize Weishu in situ gel forming prescription,and to study on its release property.METHODS Taking the gelling temperature and adhesion as indexes,the temperature-sensitive in situ gel forming matrix ratio,drug loading,bio-adhesive material type and dosage were screened,then the optimal molding process was determined,and the thermal reversibility of the best prescription was examined.The in vitro drug release was also studied by releasing test.RESULTS The best prescription was P40716% and P1887.5%for the temperature-sensitive gel matrix,1%HPMC as bio-adhesive material,and the drug loading was 0.8 g·ml-1.The prescription had good thermal reversibility below50℃.By releasing test,the equation of its release was obtained:LnQ=0.915 2Ln(t)+4.293,r=0.959.This model accorded with RITGER-PEPPAS equation,and it proved that the temperature-sensitive in situ gel in the release medium drug release system was the synergistic results through Fick diffusion and gel skeleton corrosion two kinds of mechanism.The release of forsythin at 120 min reached93.95%.CONCLUSION The produced Weishu in situ gel has high bio-adhesive,good process reproducibility and better release characteristics.