A model system for prediction of the in vivo metabolism of designer drugs using three-dimensional culture of rat and human hepatocytes

Abstract

The in vitro metabolisms of 4-bromo-2,5-dimethoxyphenethylamine (2C-B), 5-methoxy-N,N-diisopropyltryptamine (5-MeO-DIPT), and 2,5-dimethoxy-4-propylthiophenethylamine (2C-T-7) were studied using TESTLIVER TM -rat and TESTLIVER TM -human, which are new three-dimensional rat and human hepatocyte culture systems, respectively. The metabolites produced in the incubation media were measured by liquid chromatographytandem mass spectrometry or gas chromatography-mass spectrometry. The data obtained with the in vitro system of rat origin were carefully compared with those obtained by rat in vivo experiments; most of the metabolites found in the in vivo experiments could be reproduced in the present threedimensional in vitro experiments, although quantitative metabolite distribution patterns obtained with the threedimensional system was somewhat different from those of in vivo experiments. Because human in vivo experiments are not possible, especially for dubious designer drugs, the in vitro experiments using the three-dimensional human hepatocyte culture system seem very useful for studying human metabolism of new designer drugs as an alternative to human experiments.Keywords Three-dimensional culture Á Hepatocyte Á Metabolism Á 2C-B Á 5-MeO-DIPT Á 2C-T-7

Evaluation ofin vitrometabolic systems for common drugs of abuse. 1. Cocaine

“…Fandino et al did note appreciable variability of enzymatic activity between microsomal preparations derived from various tissues, specifically a lack of oxidative metabolite production in kidneyand brain-based assays. However, as has been noted in other studies, xenobiotic metabolism can vary both qualitatively and quantitatively between species (Kanamori et al, 2011;Roberts et al, 1991), suggesting caution when drawing conclusions based on cross-species assays. Species-dependent differences in COC metabolite profiles were recently examined by Yao et al, demonstrating not only quantitative and qualitative shifts in metabolism but also suggesting that the primary route of oxidative COC metabolism may differ between species (Yao et al, 2013).…”

“…Recently, in vitro assays have been employed to designate major metabolites of ''designer drugs,'' including amphetamine, phencyclidine and D 9 -tetrahydrocannabinol (THC) analogs (Kanamori et al, 2011;Peters & Meyer, 2011). These studies were able to facilitate the development of analytical detection methods for numerous emerging designer drug analogs whose in vivo metabolism had not been reported.…”

“…In the drug planning and development stages, pharmaceutical researchers utilize various in vitro assays to model the in vivo production of potentially toxic and reactive metabolites, in addition to detoxified products, by both Phase I and Phase II biotransformation (Evans et al, 2005). To a much more limited extent, these assays have also been employed by forensic toxicologists to designate primary metabolic products of abused substances (Kanamori et al, 2011;Peters & Meyer, 2011).…”

Covalent Protein Adduction by Drugs of Abuse

“…116,117 These studies have facilitated the development of analytical detection methods for numerous emerging designer drug analogs whose in vivo metabolism has not been reported. In the present study, several such systems were effective in producing a set of biotransformation products of cocaine, methamphetamine, and morphine, including all known major primary metabolites and numerous common secondary metabolites.…”