Beijing Wellso Pharmaceutical Co., Ltd.

A simple and sensitive method of high performance liquid chromatog. tandem mass spectrometry (HPLC-MS/MS) was established to determine rotundine in human plasma and urine.The plasma and urine samples were precipitated by acetonitrile and then were directly injected into the HPLC-MS/MS system.Agilent-ZORBAX C₁₈ (2.1 mm×150 mm, 5μm) column was used with acetonitrile-0.2% formic acid solution=85:15 as the mobile phase in gradient elution.Rotundine and the internal standard, diazepam, were separated by HPLC and quantitated by MS/MS with electrospray ionization (ESI) and multiple reaction monitoring (MRM) in the pos. ion mode.The most intense [M-H]⁺ MRM transition of rotundine at m/z356.3→192.3 was used for the quantitation and the transition at m/z 285.0→193.0 was used to monitor diazepam.The minimal detectable plasma concentration was 2.5 ng·mL^-1, the calibration curve was linear at 2.5-1 000 ng·mL^-1 (r=0.999 4), and the intra-day and inter-day RSDs were less than 10%.The average recoveries were 91.4%-109.2% and 88.63%-115.8%: resp. for rotundine in human plasma and urine.The method is simple, sensitive and accurate.It is suitable for pharmacokinetic study of rotundine in human plasma and urine.

Azelnidipine was synthesized from di-Ph amine and epichlorohydrin by nucleophilic substitution, cyclization, esterification, addition and reduction with Pd/C to give 1-benzhydrylazetidin-3-yl amidinoacetate acetic acid salt (5), which was subjected to Michael addition with 2-(3-nitrobenzylidene) acetyl iso-Pr acetate (6) and then cyclization.The overall yield was about 40%.