An HPLC method for the quantitative determination of propranolol, 4-hydroxypropranolol, and propranolol glycol in human plasma is described. The limits of sensitivity for the method were: 1 ng/ml propranolol; 5 ng/ml 4-hydroxypropranolol; and 1 ng/ml propranolol glycol. Data obtained from 6 healthy volunteers given a single 160 mg oral dose of propranolol revealed mean (+/- SEM) peak plasma levels of 31 +/- 10 ng/ml for 4-hydroxypropranolol and 9 +/- 2 ng/ml for propranolol glycol. These plasma levels were less than the peak concentrations recorded for propranolol (123 +/- 34 ng/ml. The rates of plasma decay of these two metabolites were greater than that observed for propranolol.
Chromatography, High Pressure Liquid Fluorometry