Determination of megestrol acetate in rat plasma by HPLC

Objective:To establish a HPLC method for the determination of megestrol acetate in rat plasma.Methods:After being extracted by hexane with danazol as internal standard(IS),the plasma sample was analyzed on a Thermo BDS Hypersil C18 column(250mm×4.6mm,5μm) at 30℃.The mobile phase consisted of methanol-water(75∶25) with a flow rate of 1.0mL·min-1.The detection wave length was 288nm.Results:The peak area ratios of megestrol acetate to danazol(Y) showed linear relationship with the concentrations of megestrol acetate in plasma(X) over the range of 0.032～4μg·mL-1(the linear equation was Y=2.70X+2.71×10-2,r=0.9991).The limit of quantification was 0.016μg·mL-1.The limit of detection was below 0.0064μg·mL-1.The intra-and inter-day precisions were both less than 15%.The methodology recovery was 95%~105%,while the extraction recovery was 89%~95%.The method established was applied to determine the concentration of megestrol acetate in rat plasma for in vivo pharmacokinetic study of megestrol acetate solid dispersion prepared in our laboratory,and it was proved to be effective.Conclusion:The analysis method was accurate and reliable,which can be applicable for the determination of megestrol acetate in rat plasma.