Determination of hydralazine and its metabolites by gas chromatography-mass spectrometry.

Metabolism of the vasodilator hydralazine was investigated by in vivo and in vitro studies. Standards to identify metabolic products were synthesized. Determination and quantification of hydralazine and its metabolites were accomplished by gas chromatography-mass spectrometry. A deuterium-labeled internal standard was used for quantification. 14C-labeled internal standards were synthesized and used to demonstrate recoveries from the biological samples.