Simultaneous determination of tenidap and its stable isotope analog in serum by high-performance liquid chromatography/atmospheric pressure chemical ionization tandem mass spectrometry.

A specific high-performance liquid chromatographic/atmospheric pressure chemical ionization tandem mass spectrometric assay for the quantitative determination of tenidap and its D3 analog in human serum is described. The assay exhibited a linear dynamic range of 0.1-25 micrograms ml-1. Its precision for the two analytes over the range was 17% or better. The assay validity and its utility to investigate changes in tenidap bioequivalence and pharmacokinetics are presented.