Assay of rifampicin in serum

Abstract

Two methods for the assay of rifampicin in serum are described. The first is conventional plate diffusion method, measuring concentrations down to 0.02 μg/ml, and the second a chemical extraction followed by measurement of the inhibition of uptake of [14C]uridine by Staphylococcus aureus, which estimates in the range of 0.02 to 0.001 μg/ml. The methods were used to measure serum concentrations in man following doses of about 1050 mg and 75 mg rifampicin.