RESUMO
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.
RESUMO
OBJECTIVE:To study the effect of hydrophilic/hydrophobic nano-silica with different adding amount on the stabili-ty of lipo-emulsion. METHODS:Glycyrrhetinic acid lipo-emulsion 4 mL was taken,respectively adding into 0.5%,1.0%,1.5%(m/m,the same below) hydrophilic nSiO2,and 0.4%,0.75,1.0% hydrophobic nSiO2,incubating 2 h in 30 ℃ water;the same batch of Glycyrrhetinic acid lipo-emulsion was treated as blank control. The forms were observed under electron microscopy after treatment,absorbance value was determined,the stability parameter (KE) was calculated according to the absorbance value,then the adding amount of nSiO2 was optimized,3 batches of preparations was prepared,and the verification test was conducted. RE-SULTS:The spherical structure was Glycyrrhetinic acid lipo-emulsion in the electron microscopy,the substance wrapping its sur-face white ring (fully wrapped) or semi-circular structure (not fully wrapped) was nSiO2. KE of hydrophilic nSiO2 were 4.66%, 5.01% and -2.08%,and KE of hydrophobic nSiO2 were 3.02%,4.51% and 7.24%. The optimized adding amount of hydrophilic nSiO2 was 0.2%,0.3% and 0.4%,hydrophobic nSiO2 was 0.1%,0.2% and 0.3%;KE were 6.19%,3.05%,7.84%,8.42%, 2.41%,2.93%,respectively. The optimal adding amount was 0.3% hydrophilic nSiO2 and 0.2% hydrophobic nSiO2;the 3 batches of preparation showed the optimum stability in its own adding amount. CONCLUSIONS:Both hydrophilic and hydrophobic nSiO2 can improve the stability of Glycyrrhetinic acid lipo-emulsion,and preferably 0.3%,0.2%.