Objective To develop a HPLC method for the determination of oxymatrine in Oxymatrin Injection.Methods A RP-HPLC method with Lichrospher 5 ODS C18 column(4.6 mm? 250 mm,5 ? m) was used,and the mobile phase was the mixture of acetonnitrile-pH2.0 sulphate buffer solution(7∶93) at the f low rate of 1.0mL/min.The column temperature was 30 ℃,the UV detection wave length was 220 nm and the injection volume was 20 ? L.Results The calibra tion curve was linear(r=1.0000) in the range of 3.63～ 116.04 ? g/mL for oxyma trine.The mean recovery was 100.1 %(RSD=0.86 %,n=6).Conclusion Thi s method is effective and can be used for the determination of oxymatrine in Oxymatrine Injection.

To develop a sensitive analytical method for the determination of the genotoxic impurity mono ethyl ester of ecabet (Imp-I),an HPLC-MS/MS technique was employed. Imp-I was synthesized according to the previ-ous literatures. MS/MS and NMR were used to confirm the structure of Imp-I. A Thermo C18column was used for chromatographic separations. The mobile phase consisting of A:5 mmol/L ammonium acetate (pH adjusted to 3. 0 with formic acid)and B:acetonitrile,with a gradient program:0 min 50%B,4 min 50%B,12 min 80%B,16 min 80%B,16. 1 min 50%B and 20 min 50%B. The column was maintained at 40 °C throughout the analysis.All measurements were carried out with the mass spectrometer operated under the negative ESI mode. The selective reaction monitor (SRM)transition was used. Good linearity was obtained for Imp-I over the concentration range of 4 150 ng/mL with the coefficient of determination (r)of 0. 999. And the LOQ was 4 ng/mL. A rapid and sensi-tive HPLC-ESI-MS/MS method was developed for quantitative analysis of Imp-I in ecabet sodium APIs. This method can be of used for quality assurance of ecabet sodium in bulk commercial drugs.