Simultaneous determination of synephrine, arecoline, and norisoboldine in Chinese patent medicine Si-Mo-Tang oral liquid preparation by strong cation exchange high performance liquid chromatography.

Context: Chinese patent medicine Si-Mo-Tang oral liquid preparation (SMT) is composed of Aucklandia luppa Decne (Compositae), Citrus aurantium Linn (Rutaceae), Lindera aggregata (Sims) Kosterm (Lauraceae), and Areca catechu Linn (Arecaceae). Studies of SMT have been impeded due to the lack of quality control methods. Objective: This study aimed to simultaneously determine three alkaloids including synephrine, arecoline, and norisoboldine in SMT for the first time. Materials and methods: A strong cation exchange (SCX) high performance liquid chromatography (HPLC) method was developed to simultaneously determine synephrine, arecoline, and norisoboldine in SMT, and was compared with ion-pairing chromatography using regular reversed-phase chromatography columns. System suitability parameters of synephrine, arecoline, and norisoboldine using the SCX chromatography column were investigated. Results: Results demonstrated that good separations were achieved on an Agilent SCX (250 x 4.6 mm, 5 mu m) column at 35 degrees C. The mobile phase consisting of methanol-0.2% phosphoric acid was delivered at a constant flow of 1.0 mL min(-1) and the eluent was monitored at 215 nm. The HPLC method showed good linearity for the examined concentration ranges of 2.55-255.0, 1.30-208.0, and 2.06-201.6 mu g mL(-1) for synephrine, arecoline, and norisoboldine, respectively. The limits of quantification (S/N = 10) were 2.55, 1.30, and 2.06 mu g mL(-1), the limits of detection (S/N = 3) were 1.53, 0.78, and 1.21 mu g mL(-1), and average recoveries were 98.99, 95.63 and 99.04%, respectively, for synephrine, arecoline, and norisoboldine. Discussion and conclusion: This method has been successfully applied to determine synephrine, arecoline, and norisoboldine in Chinese patent medicine SMT.