Determination of flunarizine in rat brain by liquid chromatography-electrospray mass spectrometry

A rapid liquid chromatography-electrospray mass spectrometry (LC-ES-MS) ass ay for the determination of flunarizine (FZ) in rat brain has been develope d. A C-18 column and an isocratic elution were employed for the separation. Using post-column split, 64% of the eluent was introduced into the ES-MS s ystem for detection. The [M + H](+) (m/z 406) and a fragmented ion (m/z 203 ) were detected using selected ion monitoring. The linear range of this ass ay was good, ranging from 0.05 to 5 mu M (r(2) = 0.99). The intra- and inte r-day precisions showed relative standard deviations ranging from 1.4% to 2 .0% and 1.3% to 2.9%, respectively. The application of this newly developed method was demonstrated by examining the pharmacokinetics of FZ in rat bra in. (C) 1999 Elsevier Science B.V. All rights reserved.