Gas chromatography/mass spectrometry assays for the determination of debrisoquine and sparteine metabolites in microsomal fractions of rat liver.
Debrisoquine and sparteine are prototype substrates of a genetic deficiency in cytochrome P450-dependent drug metabolism. Sensitive assays of in vitro oxidation of sparteine and debrisoquine are required for evaluation of this polymorphism. The activities were measured by quantitative analysis of 2-dehydrosparteine and 4-hydroxydebrisoquine production, respectively, using capillary column gas chromatography coupled with mass selective ion detection. With a single extraction, separation of parent drug, metabolite, and a suitable internal standard was readily achievable. Time-dependent production of both metabolites could be detected from as little as 40 micrograms of microsomal protein. Both activities showed a maximal activity with a 240-min incubation period. The ability to simultaneously quantify the parent drug and its metabolite suggests it would also be useful for evaluation of in vivo metabolism.
Ho
J W
JW
Department of Pharmacology and Toxicology, University of Utah College of Pharmacy, Salt Lake City 84108.
Moody
D E
DE
D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics; D003647:Debrisoquin / Q000031:analogs & derivatives / Q000032:analysis / Q000378:metabolism*; D008401:Gas Chromatography-Mass Spectrometry; D066298:In Vitro Techniques; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism*; D011110:Polymorphism, Genetic; D051381:Rats; D017207:Rats, Sprague-Dawley; D013034:Sparteine / Q000031:analogs & derivatives / Q000032:analysis / Q000378:metabolism*
D013034:Sparteine; C012359:4-hydroxydebrisoquin; C044694:2-dehydrosparteine; D003577:Cytochrome P-450 Enzyme System; D003647:Debrisoquin