Reversed high-pressure liquid chromatography was applied in content determination of bufogenin in Liuying Pills. The sample was extracted with chloroform. Using the calibration curve method of external peak area for quantitation, ODS as chromatographic column, 60％ methanol as mobile phase, and detection wavelength at 298nm, the recovery reached 97.7％(CV=0.5％).

Objective:For severe skin defects which are deep to dermis, engineered skin with epidermis and dermis (bilayered) is required. Based on the success of engineering epidermis with GT/PCL electrospun membranes, our study was to investigate whether this membrane could be also used for engineering bilayered skin graft.Methods:From 2013 to 2019, we first prepared three GT/PCL electrospun membranes with different proportion (70∶30; 50∶50; 30∶70) in our laboratory; the biocompatibility of the membrane was evaluated in vitro by seeding fibroblasts or keratinocytes on the membranes. Then the outcome of GT/PCL membranes repairing skin defects in the nude mouse was investigated.Results:Cell attachment and proliferation were significantly improved with increase of gelatin. Histological analyses showed that bilayered skin engineered with GT/PCL (70∶30) group could form relatively better structure after 3 weeks of cultivation in vitro. Further in vivo transplantation studies revealed that scaffolds were not degraded in all three groups, indicating that these materials were not suitable for engineering bilayered skin although they had good biocompatibility.Conclusions:The higher gelatin membranes possess better biocompatibility. Further in vivo transplantation studies reveal that bilayered skin engineered with GT/PCL membranes is able to repair skin defects in the nude mouse.