The present work describes the O-silylation of the hydroxyl
group of metoprolol using N-methyl-N-(trimethylsilyl)trifluoroacetamide
(MSTFA) as a silylating reagent. This is followed by deter-mination of metoprolol after a derivatization procedure in human
plasma using internal standardmethodology by GC–MS. The developed
method was validated by using linearity, stability, precision,
accuracy and sensitivity parameters according to International Conference
on Harmonization (ICH) guidelines [16]. The advantages of
present method include simple and single step extraction procedure
using inexpensive chemicals and short run time. Also, this
method was used to assay the metoprolol in plasma samples
obtained from three patients with hypertension who had been
given an oral tablet of Problok (100mg metoprolol).