Determination of nefazodone and its metabolites in plasma by high-performance liquid chromatography with coulometric detection.

Nefazodone and its metabolites together with the internal standard are extracted from plasma using CN Bond-Elut sorbent columns. Chromatography and detection are performed using isocratic reversed-phase high-performance liquid chromatography (HPLC) with a CN column and coulometric end-point detection. The lower limits of quantitation for nefazodone, mCPP, and OH-nefazodone was 0.9, 0.2 and 0.6 ng ml-1 when 1 ml of plasma was extracted. The interassay relative standard deviations were less than 6% for nefazodone and its metabolites. Recovery averaged over 80%. Plasma profiles of nefazodone and its metabolites following oral dosing are presented.