ABSTRACT
OBJECTIVE:To investigate the effects of non-ionic polyacrylamide(model:NPAM 1400)alone or combined with nanoscale silica gel (nSiO2) on the stability of Glycyrrhetinic acid lipo-emulsion. METHODS:UV-spectrophotometer was used to determine absorbance of diluent at 500 nm before and after lipo-emulsion centrifugation. Using the preparation without stable excipient as blank,stability coefficient (KE) and it ratio (KE/KE blank) were calculated. Effects of different concentrations (200-600 mg/L) of non-ionic polyacrylamide on the stability of Glycyrrhetinic acid lipo-emulsion were evaluated. The optimal concentration of non-ionic polyacrylamide alone was determined primarily,and then the effects of it combined with different concentrations of hydrophilic nSiO2 (0.2％, 0.3％, 0.4％) or hydrophobic (0.2％, 0.3％, 0.5％) on the stability of Glycyrrhetinic acid lipo-emulsion were investigated. RESULTS:When adding non-ionic polyacrylamide alone,KE of Glycyrrhetinic acid lipo-emulsion mixed with 300 mg/L non-ionic polyacrylamide was the lowest,KE/KE blank was 0.22;when combined,KE of Glycyrrhetinic acid lipo-emulsion mixed with 300 mg/L non-ionic polyacrylamide and 0.2％ hydrophobic nSiO2 was the lowest,KE/KE blank was 0.27. CONCLUSIONS:Non-ionic polyacrylamide alone or combined with nSiO2 all can promote the stability of Glycyrrhetinic acid lipo-emulsion,among which 300 mg/L non-ionic polyacrylamide alone is the best.