- 著者
- Yusuke Kamiya Kentaro Handa Tomonori Miura Junya Ohori Airi Kato Makiko Shimizu Masato Kitajima Hiroshi Yamazaki
- 出版者
- The Pharmaceutical Society of Japan
- 雑誌
- Biological and Pharmaceutical Bulletin (ISSN:09186158)
- 巻号頁・発行日
- pp.b21-00769, (Released:2021-11-02)
- 参考文献数
- 39
- 被引用文献数
- 12
Physiologically based pharmacokinetic (PBPK) modeling has the potential to play significant roles in estimating internal chemical exposures. The three major PBPK model input parameters (i.e., absorption rate constants, volumes of the systemic circulation, and hepatic intrinsic clearances) were generated in silico for 212 chemicals using machine learning algorithms. These input parameters were calculated based on sets of between 17 and 65 chemical properties that were generated by in silico prediction tools before being processed by machine learning algorithms. The resulting simplified PBPK models were used to estimate plasma concentrations after virtual oral administrations in humans. The estimated absorption rate constants, volumes of the systemic circulation, and hepatic intrinsic clearance values for the 212 test compounds determined traditionally (i.e., based on fitting to measured concentration profiles) and newly estimated had correlation coefficients of 0.65, 0.68, and 0.77 (p < 0.01, n = 212), respectively. When human plasma concentrations were modeled using traditionally determined input parameters and again using in silico estimated input parameters, the two sets of maximum plasma concentrations (r = 0.85, p < 0.01, n = 212) and areas under the curve (r = 0.80, p < 0.01, n = 212) were correlated. Virtual chemical exposure levels in liver and kidney were also estimated using these simplified PBPK models along with human plasma levels. These results indicate that the PBPK model input parameters for humans of a diverse set of compounds can be reliability estimated using chemical descriptors calculated using in silico tools.
- 著者
- Tomonori Miura Yusuke Kamiya Shiori Hina Yui Kobayashi Norie Murayama Makiko Shimizu Hiroshi Yamazaki
- 出版者
- The Japanese Society of Toxicology
- 雑誌
- The Journal of Toxicological Sciences (ISSN:03881350)
- 巻号頁・発行日
- vol.45, no.11, pp.695-700, 2020 (Released:2020-11-02)
- 参考文献数
- 26
- 被引用文献数
- 1 9
Coumarin is a dietary-derived substance that is extensively metabolized by human liver to excretable 7-hydroxycoumarin. Although coumarin under daily dietary consumption is generally regarded as nontoxic, the substance is of toxicological and clinical interest because of its potential association with hepatotoxicity, which is especially evident in rats. In this study, the pharmacokinetics of coumarin were modeled after virtual oral administration in humans. The adjusted monitoring equivalents of coumarin, along with the biotransformation of coumarin to o-hydroxyphenylacetic acid (via 3,4-epoxidation) based on reported plasma concentrations from rat studies, were scaled to human coumarin equivalents using known species allometric scaling factors. Using rat and human liver preparations, data on the rapid in vitro metabolic clearance for humans (~50-fold faster than in rats) were obtained for in vitro–in vivo extrapolation. For human physiologically based pharmacokinetic (PBPK) modeling, the metabolic ratios to o-hydroxyphenylacetic acid and 7-hydroxycoumarin were set at minor (0.1) and major (0.9) levels for the total disappearance of coumarin. The resulting modeled plasma concentration curves in humans generated by simple PBPK models were consistent with reported simulated coumarin maximum concentrations. These results provide basic information to simulate plasma levels of coumarin and its primary metabolite 7-hydroxycoumarin or its secondary activated metabolite o-hydroxyphenylacetic acid (via 3,4-epoxidation) resulting from dietary foodstuff consumption. Under the current assumptions, little toxicological impact of coumarin was evident in humans, thereby indicating the usefulness of forward dosimetry using PBPK modeling for human risk assessment.