Solid-phase extraction of midazolam and two of its metabolites from plasma for high-performance liquid chromatographic analysis.

A rapid, sensitive and selective assay of midazolam and two of its metabolites in plasma, based on high-performance liquid chromatography, has been developed. The compounds are subjected to solid-phase extraction, using C18 cartridges (Bond-Elut). Recoveries are in excess of 90% for midazolam and its metabolites. The limit of quantitation of the assay is 50 ng/ml of plasma for each compound.