Analysis of benzimidazoles in body fluids by high-performance liquid chromatography.

A simple assay for benzimidazole in plasma and GI fluids using high-performance liquid chromatography was developed. The benzimidazoles were extracted using ether and were chromatographed with methanol-ammonium carbonate mixtures as the eluting solvents. Benzimidazole was detectable in 4 ml of plasma or GI fluid to a limit of 20 ng/ml.