Study on the chiral separation of securinine by high-performance capillary electrophoresis and its stereoselective metabolism in rat / 药学学报

<p><b>AIM</b>To establish a high-performance capillary electrophoresis (HPCE) chiral separation method for d-securinine and l-securinine, and use this method to investigate the stereoselective metabolism process of d- and l-securinine in Wistar rats.</p><p><b>METHODS</b>The electrophoretic condition and parameters were investigated and the optimized conditions were as following: the electrophoretic medium was 40 mmol.L-1 Tris-H3PO4 buffer (pH adjusted to 6.0 with H3PO4) containing 32 mmol.L-1 HP-beta-CD as chiral selector. Determination was carried out with a UV detector at 254 nm. The separations were performed at 16 degrees C with a positive voltage of 15 kV. Samples were injected into the capillary by pressure for 6 s. The biological samples (urine, bile, plasma and feces) of rats were alkalized and extracted with ethyl acetate.</p><p><b>RESULTS</b>The experimental results showed that the concentration of HP-beta-CD, the concentration of the running buffer and the pH value of the buffer were the main important factors which effected the resolution. d-Securinine and l-securinine were separated at baseline level under the determination conditions. The determination was not interfered by endogenous components and metabolites. After i.p. administration, the rats excreted more d-securinine than l-securinine through bile, urine and feces. The metabolism process in rats was stereoselective.</p><p><b>CONCLUSION</b>This method is simple, reliable and suitable for studying the stereoselective metabolism of securinine in rats.</p>

The metabolic transformation of (-)-securinine / 药学学报

<p><b>AIM</b>To study the in vitro and in vivo metabolism of (-)-securinine.</p><p><b>METHODS</b>The metabolic transformation of (-)-securinine was studied by using phenobarbital-induced rat liver microsomal incubate containing the NADPH-generating system in vitro and the constitution of the system was optimized. A reversed phase HPLC method was established to analyze the parent drug and its metabolites. The major metabolites were isolated and purified by liquid-liquid extraction, preparative TLC and HPLC, and their structures were elucidated as 6-hydroxyl securinine, 6-carbonyl securinine, 5 beta-hydroxyl securinine and 5 alpha-hydroxyl securinine by 1HNMR, 13CNMR and MS spectral analysis. An HPLC method was developed to analyze securinine and its metabolites in biofluids (bile, urine) of rat. The bile, urine and their enzymatic hydrolyzed samples of the rat i.p. administrated with (-)-securinine were determined by using this method.</p><p><b>RESULTS</b>Four main metabolites of (-)-securinine in rat hepatic microsome incubation were obtained and their structures were elucidated. Metabolites from in vitro study were confirmed in biofluids (bile, urine) which were collected from rats given securinine i.p. It was suggested that 6-hydroxyl securinine was excreted in conjugated form as well by analyzing enzymatic hydrolyzed bile.</p><p><b>CONCLUSION</b>The main metabolic pathway of (-)-securinine in vitro and in vivo is basically elucidated.</p>