CAD MIKE spectrometry: a novel approach to the study of drug metabolism

A method for the screening and identification of drug metabolites directly in crude urine and tissue extracts is described. The method, an application of an MS/MS technique, CAD MIKE spectrometry (collisionally activated decompostion mass analyzed ion kinetic energy spectrometry), greatly reduces the time of analysis and the amount of biological sample required. The structure of the metabolites is elucidated by interpretation of the CAD MIKE spectra obtained by selection and collision-induced decomposition of targeted molecular ions. Application of this technique to the study of biotransformation in the rat of the anthelmintic drug Nitroxynil (3-iodo-4-hydroxy-5-nitrobenzamide) has provided unequivocal identification of its metabolutes in urine and liver tissue in less than 3 days.