James D Terish, Suresh Kumar, Ramesh N and Sasi jith SL
An analytical procedure was developed/validated for the quantification of Artemether and its metabolite, Dihydroartemisinin (DHA), in human plasma. The analyte and its metabolite were extracted from human plasma by solid phase extraction technique, followed by simple isocratic chromatographic condition with mobile phase Acetonitrile: Ammonium formate buffer 2 mM (80:20 v/v) and mass spectrometric detection that enables detection at nanogram levels. Artemisinin was used as the internal standard. A Polaris A, C18, 50 X 4.6 mm, 5μm column provided chromatographic separation of the analyte which was followed by detection with mass spectrometry. The mass transition ion pair was followed as m/z 316.1 / 267.1 for Artemether, m/z 302.1 / 267.1 for Dihydroartemisinin and m/z 300.2 / 209.2 for internal standard using ESI Positive ionization mode. The retention time of analyte (Artemether and Dihydroartemisinin) and internal standard was 2.7, 1.6 and 1.8 minutes respectively. The proposed method has been validated with linear range of 2.386-200.787 ng/mL for Artemether and 2.391- 201.252 ng/mL for Dihydroartemisinin. Estimation of Artemether and its metabolite dihydroartemisinin in biological matrices has usually been difficult, with sensitivity being unease. The absence of any matrix effects was observed. Both intra-day and inter-day accuracy and precision showed good reproducibility. The method developed produce recovery of for Artemether was 92.57%, and for Dihydroartemisinin was 93.89%. The LC-MS/MS method described is sensitive, selective and linear for the wide range of concentrations for Ethambutol in human plasma. The validated method well suited for application in bioequivalence study of 20 mg Artemether tablet.
