Prediction of differences inin vivooral clearance ofN,N-dipropyl-2-[4-methoxy-3-(2-phenylethoxy)phenyl]ethylamine monohydrochloride (NE-100) between extensive and poor metabolizers fromin vitrometabolic data in human liver microsomes lacking CYP2D6 activity and recombinant CYPs

Abstract

1. It has previously been reported that N,N-dipropyl-2-[4-methoxy-3-(2-phenylethoxy)phenyl]-ethylamine monohydrochloride (NE-100) was predominantly metabolized by cytochrome P450 (CYP) 2D6 in human liver microsomes (HLM). In the present study, the contribution of CYP forms involved in the formation of the major metabolites of NE-100 in human liver lacking CYP2D6 activity (PM-HLM) has been predicted by use of in vitro kinetic data on recombinant CYPs microsomes (rCYPs). 2. In PM-HLM, NE-100 is predicted to be metabolized to N-despropyl-NE-100 (NE-098), p-hydroxy-NE-100 (NE-152) and m-hydroxyl-NE-100 (NE-163), but not to O-demethy-NE-100 (NE-125), which is a major metabolite in pooled human liver microsomes (EM-HLM). The relative activity factor approach assumed that NE-098 formation is predominantly catalysed by CYP3A4 and CYP2C9 and the NE-152+163mix (a mixture of two hydroxylated metabolites, NE-152 and NE-163) formation is only catalysed by CYP3A4. 3. The predicted contribution rates of CYP3A4 and CYP2C9 for NE-098 formation were 58.1 and 34.6%, respectively, in PM-HLM. These predicted results were strongly supported by kinetic and inhibition studies using PM-HLM. The intrinsic clearance of NE-100 predicted from rCYPs (the predicted CLint-HLM-total) corresponded to those observed from EM- and PM-HLM (the observed CLint-HLM). 4. The in vivo oral clearance (CLoral) of NE-100 in extensive metabolizers and poor metabolizers of CYP2D6 was predicted to be 50times higher in extensive metabolizers than poor metabolizers using in vitro-in vivo scaling method based on the dispersion model. These data suggest that polymorphism of CYP2D6 might greatly affect NE-100 metabolism in vivo.

Sex-Dependent Environmental Health Risk Analysis of Flupyradifurone

“…Remarkably, male, as compared to female, rats produced greater amounts of difluoroethyl-amino-furanone (DFEAF) and (6-chloropyridin-3-yl) methanol (CHMP) via the preferential phase I biotransformation of C–N hydrolysis . N-dealkylation of the ethylamine bond (C–N at position 7) caused cleavage of the FPF molecule into two parts, DFEAF and CHMP, which might be induced by the CYP450 isoform 2D6, CYP3A4, and CYP2C9. , CHMP can be further oxidized into 6-chloronicotinic acid (6-CNA), which can be conjugated with glycine in the following phase II reaction, which yields the final product CNA-Gly. Interestingly, the urine samples of female rats had a greater concentration of CHMP metabolites than those of male rats.…”

Prediction of the Effects of Genetic Polymorphism on the Pharmacokinetics of CYP2C9 Substrates from In Vitro Data

“…For example, the oral clearances of warfarin in *1/*1, *2/*2, and *3/*3 subjects varies considerably (39.6, 12.8, 3.7 L/h) (16), but those of losartan (64, 57, 39 L/h) (17) and diclofenac (20,30,23 L/h) (18) do not show large differences among subjects with mutant alleles. These kinds of substrate-specific effects of CYP2C9 mutations on the pharmacokinetics are attributed to differences in the contribution of CYP2C9 to the overall clearance of drugs and differences in the decrease in the intrinsic clearances by mutated enzymes.…”

“…The quantitative contribution of CYP2C9 to overall metabolic clearance has been reported to be an important factor in extrapolating in vitro data to in vivo situations (19). Some studies have extrapolated in vitro data to in vivo situations, considering polymorphisms of metabolic enzymes and contribution of the CYP isozyme to the metabolic clearance (20). Furthermore, a successful in vitro to in vivo extrapolation of warfarin metabolism considering CYP2C9 polymorphisms has been reported (21,22).…”

Prediction of Hepatic Clearance in Human From In Vitro Data for Successful Drug Development

“…The RAF represents the ratio of the metabolic activity of the CYP-isoform-specific marker substrate in the human liver microsomes to that in the complementary-DNA-expressed system for the same isoform, and the value quantitatively facilitates bridging metabolic activities between both in vitro systems (115)(116)(117)(118). Successful extrapolations of in vitro metabolic clearance obtained in the recombinant CYP isoforms to that in vivo have been well documented for the compounds with less significant contribution of hepatic uptake to overall clearance in human (115,(119)(120)(121). This approach cannot only provide quantitative information on the relative contribution of CYP isoform(s) involved in the metabolism of the compound of interest but also the preliminary prediction of hepatic clearance attributable to the CYP-mediated metabolism in human at discovery stage (87,116,122,123).…”