In vitro metabolite profiling

Generally based on shared in vitro metabolite profile with humans. Pharmacologic activity is a secondary consideration. Rodent and nonrodent species are easily identified. 

In vitro metabolite profiling (including human ADME) (radiolabel)... 

Full in vitro safety profiling (see ADMEI), PK/ PD, metabolite profile, multiple dose study... 

Liquid chromatography is routinely used for the quantitative analysis of a drug and its metabolites in radiolabeled in vitro metabolism experiments and in humans and animal ADME studies. Online radio-flow detection (RFD) and offline microplate scintillation counting (MSC) are the most commonly used radiochromatographic techniques in radiolabeled metabolite profiling and quantification (Boernsen et al., 2000 Nassar et ah, 2003 Bruin et al., 2006). LC/RFD is compatible with ESI mass spectrometry and provides high analytical speed and excellent separation resolution (Athersuch et al., 2008). 

Flavonols are the widest spread metabolites in higher plants and predominantly accumulate as glycosides. In vitro biochemical analyses and in planta metabolite profiling have identified a number of interesting Arabidopsis GTs involved in flavonol glycoside biosynthesis, such as UGT78D1 and UGT89C1 which catalyze the 3-OH and 7-OH rhamnosylation of flavonols... 

Ni et al. [143] investigated the profile of the major metabolites of primaquine produced by in vitro liver microsomal metabolism, with silica gel thin-layer and high performance liquid chromatography analysis. Results indicated that the liver microsomal metabolism could simultaneously produce both 5-hydroxyprimaquine (quinoline ring oxidation product) and carboxyprimaquine (side-chain oxidative deamination product). However, the quantitative comparative study of microsomal metabolism showed that the production of 5-hydroxyprimaquine was far much higher than that of carboxyprimaquine. 

Ni et al. [144] also investigated the profiles of major metabolites of primaquine produced from liver microsomal and mitochondrial metabolism, in vitro by silica gel thin-layer and reversed-phase high performance liquid chromatography. The results... 

These in vivo and in vitro human metabolism studies indicate that pyrethroids undergo rapid metabolism and elimination as observed in rats, and qualitative metabolic profiles (e.g., kinds of metabolites) of pyrethroids are assumed to be almost the same between humans and rats, suggesting that a large database of animal metabolism of pyrethroids could provide useful information for the evaluation of behavior of pyrethroids in humans. Nowadays, human pesticide dosing studies for regulatory propose are severely restricted in the US, and thus detailed comparison of in vitro metabolism (e.g., metabolic rate constants of pathways on a step-by-step basis) using human and animal tissues could be an appropriate method to confirm the similarity or differences in metabolism between humans and animals. 

Green et al. (1986) compared the metabolism of amphetamine in isolated hepatocyte suspensions from rat, dog, squirrel, monkey, and human livers. The metabolite profile of hepatocytes from each species corresponded to the profile of urinary metabolites identified previously. These results indicate that species-specific differences in the metabolic activation of compounds seen in vivo can be reproduced in vitro by the utilization of primary hepatocyte cultures. 

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