Determination of bezafibrate, ciprofibrate and fenofibric acid in human plasma by high-performance liquid chromatography

Abstract A selective high-performance liquid chromatographic method to assess either bezafibrate, ciprofibrate or fenofibric acid plasma levels is described. Drugs are extracted with diethyl ether, after acidification with HCl. An isocratic acetonitrile-0.02 M H 3 PO 4 (55:45) mobile phase, a C 18 (5 μm) column and UV detection are used. The LOQ found was 0.25 μg/ml for the three fibrates. Intra- and inter-assay accuracy ranges were 90–107% and 82–111%; 96–115% and 94–107%; 94–114% and 94–126% for bezafibrate, ciprofibrate and fenofibric acid, respectively. Intra- and inter-assay precision (C.V.% ranges) were 1.72–3.06% and 2.66–7.67%; 1.88–4.64% and 0.62–2.99%; 1.26–4.69% and 3.56–7.17% for the three fibrates studied. Its sensitivity, accuracy and precision make it a useful tool for monitoring plasma levels of these drugs in a clinical setting and for research purposes.