A RAPID AND SENSITIVE ELECTRON-CAPTURE GAS-CHROMATOGRAPHIC PROCEDURE FOR ANALYSIS OF METOPROLOL IN RAT-BRAIN AND HEART

A procedure for analysis of metoprolol-utilizing extraction followed b y derivatization with pentafluoropropionic anhydride and analysis on a gas chromatograph equipped with a fused silica capillary column, an e lectron-capture detector and a printer/integrator is described. Propra nolol was carried through the procedure as internal standard. The pent afluoropropionyl derivative of metoprolol yields a sharp peak on the g as chromatograph, and the structure of the derivative was confirmed us ing combined gas chromatography-mass spectrometry. The analytical meth od is linear, sensitive and reproducible and has been applied to analy sis of metoprolol in brain and heart from rats treated with metoprolol intraperitoneally. Pretreatment of the rats with the antidepressant d esipramine prior to metoprolol administration resulted in a marked inc rease in levels of metoprolol in both brain and heart, indicating a ph armacokinetic drug-drug interaction between desipramine and metoprolol . (C) 1997 Elsevier Science Inc.