DETERMINATION OF URAPIDIL HYDROCHLORIDE IN RABBIT PLASMA BY LC-MS-MS AND ITS APPLICATION TO A PHARMACOKINETIC STUDY

摘要

A sensitive and selective liquid chromalography tandem mass speclromelry (LC-MS-MS) method for determination of urapidil hydrochloride in rabbit plasma was developed and validated. After addition of doxapram hydrochloride as the internal standard (IS), protein precipitation by Iff/a Irichloroacetic acid was used as the sample preparation. Chromatographic separation was achieved on a Zorbax SB-C18 (2.1mm x 50 mm, 3.5mum) column with acetonitrile-waler as the mobile phase with gradient elulion. Eleclrospray ionizalion (ESI) source was applied and operated in positive ion mode; multiple reaction monitoring (MRM) mode was used to quantification using target fragment ions m/z 387.9-> 204.6 for urapidil hydrochloride and m/z 378.9-> 291.8 for the IS. Calibration plots were linear over the range of 5-1000 ngj mL for urapidil hydrochloride in plasma. Lower limit of quanlilalion (LLOQ) for urapidil hydrochloride was 5ng/mL. Mean recovery of urapidil hydrochloride from plasma was in the range 93.5%-96.4'A. RSD of intra-day and inter-day precision were both less than 12%. This developed method is successfully used in pharmacokinelic study of urapidil hydrochloride in rabbit.