Determination of propranolol and 4-hydroxypropranolol in human plasma by high-performance liquid chromatography.

A high-performance liquid chromatographic method was developed to determine the levels of propranolol and its major metabolite, 4-hydroxypropranolol, in human plasma. The limits of determination are 10 ng ml-1 of propranolol and 5 ng ml-1 of 4-hydroxypropranolol using a 0.5-ml plasma sample. The stability of plasma samples stored at -30 degrees C for up to 2 months was also tested. No stabilising antioxidants were added to the samples.