[Show abstract][Hide abstract] ABSTRACT: A rapid, sensitive and accurate high performance liquid chromatographic (HPLC) method for determination of propranolol in dog plasma is described. Propranolol was extracted from dog plasma using a mixture of n-heptane and isoamyl alcohol (98.5:1.5, v/v) and separated on a C18 column. The mobile phase consisting of a mixture of acetonitrile-water (containing of 1% acetic acid and 0.2 % of triethylamine) (28:72, v/v) was delivered at a flow rate of 0.9 ml/min. Linearity was obtained over the concentration range of 2.0–500.0 ng/ml for propranolol and the lower limit of quantitation was 2.0 ng/ml. For each level of QC samples, inter-and intra-run precision was less than 4.3% and 5.5% (relative standard deviation (R.S.D.), respectively, and the bias was within ±4.0%. This method was successfully applied to the pharmacokinetic study of a propranolol formulation after oral administration to Beagle dog s.