DETERMINATION OF SYNEPHRINE FROM CHINESE MEDICINAL DRUGS ORIGINATING FROM CITRUS SPECIES BY ION-PAIR HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

A simple and precise method was established for the determnation of synephrine in Chinese crude drugs from Citrus plants using high-performance liquid chromatography with sodium dodecyl sulphate (SDS) as ion-pair reagent. Synephrine is known as a sympathomimetic drug contained in Chinese crude drugs from Citrus plants, namely Aurantii nobilis Pericarpium (Japanese name "Chinpi"), Aurantii fructus Immaturus ("Kijitsu"), "Kikoku" and "Seihi". The optimum conditions for extracting synephrine from these Chinese crude drugs was a 15-min reflux with water-acetonitrile-SDS-H3PO1 (65:35:0.5:0. 1) as the mobile phase. Synephrine was eluted within 13 min without interference from co-existing components using an ODS column and SDS as an ion-pair reagent. The results revealed that synephrine was present at levels of 0.174-0.566% in the Chinese crude drugs, which were 1.3-2.2 times higher than those reported previously.