An evaluation of metabolite profiling of six drugs using dried blood spot.

Dry blood spot (DBS) analysis has been extensively used for the quantitative analysis of drugs by mass spectrometry; however, utilization of DBS for qualitative metabolite profiling has been very limited. In the present study, we investigated the use of DBS for metabolite profiling of genistein, carbamazepine, losartan, sunitinib, sildenafil and zoniporide representing a range of Phase I and Phase II biotransformations following oral and intravenous dosing to rats. Plasma and DBS were collected for PK and metabolite profiling.

In Vitro and In Vivo Correlation of Hepatic Fraction of Metabolism by P450 in Dogs.

1-Aminobenzotriazole (ABT) has been widely used as a nonspecific mechanism-based inhibitor of cytochrome P450 (P450) enzymes. It is extensively used in preclinical studies to determine the relative contribution of oxidative metabolism mediated by P450 in vitro and in vivo. The aim of present study was to understand the translation of fraction metabolized by P450 in dog hepatocytes to in vivo using ABT, for canagliflozin, known to be cleared by P450-mediated oxidation and UDP-glucuronosyltransferases-mediated glucuronidation, and 3 drug discovery project compounds mainly cleared by hepatic metabolism.

Comparison between Radioanalysis and F Nuclear Magnetic Resonance Spectroscopy in the Determination of Mass Balance, Metabolism, and Distribution of Pefloxacin.

Mass balance and metabolism studies using radiolabeled substances are well recognized as an important part of the drug development process. In this study, we directly assessed the use of fluorine nuclear magnetic resonance (F NMR) to achieve quantitative mass balance, metabolism, and distribution information for fluorinated compounds, without the need for radiolabeled synthesis or study. As a test case, the disposition of pefloxacin, a fluoroquinolone antibiotic, was evaluated in rats using quantitative F NMR in parallel with a radiolabeled study.