Simple and sensitive determination of nisoldipine in plasma using liquid chromatography-tandem mass spectrometry.

A simple and rapid quantification method was developed for determining nisoldipine in plasma. After a simple protein precipitation with a mixture of 10% of zinc sulfate and methanol, the analytes were chromatographed on a reversed-phase C(18) column, and detected by MS/MS. The assay precision was less than 10.7%, and the accuracy ranged from 86 to 112%. The limit of quantification was 0.1 ng/ml. This method was used to measure the plasma concentration of nisoldipine from healthy subjects after a single 5-mg oral dose of nisoldipine.