10.22376/ijpbs.2019.10.1.p1-12 Volume 1 Issue 1 2010 (January - March) This paper describes a gas chromatography-mass spectrometry (GC-MS) method with selected ion monitoring (SIM) for determination of metoprolol in rabbit plasma. Metoprolol and internal standard (IS) atenolol were extracted from plasma and cleaned up by using a single step liquid-liquid extraction. Derivatization was carried out using lessThan i greaterThan N-Methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA). lessThan /i greaterThan Calibration curves were linear over the concentration range 15-500 ng mL lessThan sup greaterThan -1 lessThan /sup greaterThan . Intra- and inter-day precision values for metoprolol in rabbit plasma were less than 6.4, and accuracy (relative error) was better than 8.8%. The analytical recovery of metoprolol from rabbit plasma averaged out to 91.20%. The limits of detection (LOD) and quantification (LOQ) of metoprolol were 5.0 and 15 ng mL lessThan sup greaterThan -1 lessThan /sup greaterThan , respectively. Also the developed and validated GC-MS method was successfully applied to a pharmacokinetic study of metoprolol in New Zealand white rabbits. B. Yilmaz and M. C. Cavus Metoprolol, Gas chromatography-mass spectrometry (GC-MS), Validation and Pharmacokinetics -