Qualitative and quantitative studies on impurities in schizonepetin, a novel antiviral agent, using HPLC, NMR and MS

Abstract

Schizonepetin is a new naturally occurring monoterpene with antiviral activity. Three unknown related impurities were observed in analysis of schizonepetin bulk drug. A semi-preparative liquid chromatography was used for isolation of the three impurities. Three impurities were characterized as (-)-mintlactone (Impurity I), (R)-(+)-pulegone (Impurity II) and (+)-menthofuran (Impurity III) by a variety of spectral data (IR, UV, MS, 1H-NMR, 13C-NMR, DEPT and 2D-NMR). The simultaneous quantitative determination of schizonepetin and its impurities (Imp-I, II and III) was performed by reversed-phase HPLC method with UV detection at 220 nm. The method shows good precision, sensitivity, linearity (between 0.025 and 1.0 mg mL -1) and robustness. © 2013 Springer-Verlag Berlin Heidelberg.