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Bernstein AS, Prasad B, Schlosser PM, Kapraun DF. A Model Template Approach for Rapid Evaluation and Application of Physiologically Based Pharmacokinetic Models: Extension to Volatile Organic Compounds. Toxicol Sci 2023; 192:kfad021. [PMID: 36869685 DOI: 10.1093/toxsci/kfad021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2023] Open
Abstract
Chemical risk assessors use physiologically based pharmacokinetic (PBPK) models to perform dosimetric calculations, including extrapolations between exposure scenarios, species, and populations of interest. Assessors should complete a thorough quality assurance (QA) review to ensure biological accuracy and correct implementation prior to using these models. This process can be time-consuming, and we developed a PBPK model template that allows for faster, more efficient QA review. The model template consists of a single model "superstructure" with equations and logic commonly found in PBPK models, allowing users to implement a wide variety of chemical-specific PBPK models. QA review can be completed more quickly than for conventional PBPK model implementations because the general model equations have already been reviewed and only parameters describing chemical-specific model and exposure scenarios need review for any given model implementation. We have expanded a previous version of the PBPK model template by adding features commonly included in PBPK models for volatile organic compounds (VOCs). We included multiple options for representing concentrations in blood, describing metabolism, and modeling gas exchange processes to allow for inhalation exposures. We created PBPK model template implementations of published models for seven VOCs: dichloromethane, methanol, chloroform, styrene, vinyl chloride, trichloroethylene, and carbon tetrachloride. Simulations performed using our template implementations matched published simulation results to a high degree of accuracy (maximum observed percent error: 1%). Thus, the model template approach can now be applied to a broader class of chemical-specific PBPK models while continuing to bolster efficiency of QA processes that should be conducted prior to using models for risk assessment applications.
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Affiliation(s)
- Amanda S Bernstein
- Oak Ridge Institute for Science and Education, Oak Ridge, TN, USA
- Center for Public Health and Environmental Assessment, Office of Research and Development, US Environmental Protection Agency, Durham, North Carolina, USA
| | - Bidya Prasad
- Center for Public Health and Environmental Assessment, Office of Research and Development, US Environmental Protection Agency, Durham, North Carolina, USA
| | - Paul M Schlosser
- Center for Public Health and Environmental Assessment, Office of Research and Development, US Environmental Protection Agency, Durham, North Carolina, USA
| | - Dustin F Kapraun
- Center for Public Health and Environmental Assessment, Office of Research and Development, US Environmental Protection Agency, Durham, North Carolina, USA
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Take M, Takeda T, Ishikawa H, Matsumoto M, Nagano K, Fukushima S. Area under the blood concentration-time curve (AUC) of ethylbenzene concentration in rats: relationship to inhalation and oral administration route-dose. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2020; 55:1596-1603. [PMID: 33054527 DOI: 10.1080/10934529.2020.1827653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 09/17/2020] [Accepted: 09/19/2020] [Indexed: 06/11/2023]
Abstract
For human risk assessment of toxic chemicals, especially volatile organic compounds (VOCs), the Ministry of the Environment, Government of Japan, has called for the interconversion of inhalation-dose and oral-dose data, two common exposure routes. To address this issue, the present study investigated the time-course changes of ethylbenzene (EB) concentrations in the blood of rats during and after 6-hr inhalation exposure to EB (25, 50, 100, and 200 ppm) and after oral administration of EB by a single oral gavage (25, 50, 100, and 200 mg/kg) of EB. The Area Under the blood concentration-time Curve (AUC) at each blood collection time point (0, 30, 60, 120, 180, 360, 420, 540, and 1440 min, after starting exposure) was determined. The inhalation dose of 25 ppm corresponded closely to the oral administration of 25 mg/kg・bw (r value of 0.859), and the inhalation dose of 200 ppm correlated with the oral administration of 100 mg/kg・bw (r value of 0.948). These results suggest that this comparison using the AUC data at each blood collection time point is valuable for understanding the route- and dose-effects of EB. This study will improve risk assessment of human exposure to EB and other VOCs.
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Affiliation(s)
- Makoto Take
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, Hadano, Kanagawa, Japan
| | - Tomoki Takeda
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, Hadano, Kanagawa, Japan
| | - Hiroaki Ishikawa
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, Hadano, Kanagawa, Japan
| | - Michiharu Matsumoto
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, Hadano, Kanagawa, Japan
| | - Kasuke Nagano
- Nagano Toxicologic-Pathology Consulting, Hadano, Kanagawa, Japan
| | - Shoji Fukushima
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, Hadano, Kanagawa, Japan
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Take M, Takeuchi T, Hirai S, Takanobu K, Matsumoto M, Fukushima S, Kanno J. Distribution of 1,2-dichloropropane in blood and other tissues of rats after oral administration. J Toxicol Sci 2017; 42:121-128. [DOI: 10.2131/jts.42.121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Makoto Take
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety
| | - Tetsuya Takeuchi
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety
| | - Shigeyuki Hirai
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety
| | - Kenji Takanobu
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety
| | - Michiharu Matsumoto
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety
| | - Shoji Fukushima
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety
| | - Jun Kanno
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety
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Boobis AR, Cohen SM, Dellarco VL, Doe JE, Fenner-Crisp PA, Moretto A, Pastoor TP, Schoeny RS, Seed JG, Wolf DC. Classification schemes for carcinogenicity based on hazard-identification have become outmoded and serve neither science nor society. Regul Toxicol Pharmacol 2016; 82:158-166. [DOI: 10.1016/j.yrtph.2016.10.014] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 10/20/2016] [Accepted: 10/21/2016] [Indexed: 12/27/2022]
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Take M, Takeuchi T, Haresaku M, Matsumoto M, Nagano K, Yamamoto S, Takamura-Enya T, Fukushima S. Estimation of chloroform inhalation dose by other routes based on the relationship of area under the blood concentration-time curve (AUC)-inhalation dose to chloroform distribution in the blood of rats. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2014; 49:253-261. [PMID: 24279616 DOI: 10.1080/10934529.2014.846191] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The present study investigated the time-course changes of concentration of chloroform (CHCl3) in the blood during and after exposure of male rats to CHCl3 by inhalation. Increasing the dose of CHCl3 in the inhalation exposed groups caused a commensurate increase in the concentration of CHCl3 in the blood and the area under the blood concentration-time curve (AUC). There was good correlation (r = 0.988) between the inhalation dose and the AUC/kg body weight. Based on the AUC/kg body weight-inhalation dose curve and the AUC/kg body weight after oral administration, inhalation equivalent doses of orally administered CHCl3 were calculated. Calculation of inhalation equivalent doses allows the body burden due to CHCl3 by inhalation exposure and oral exposure to be directly compared. This type of comparison facilitates risk assessment in humans exposed to CHCl3 by different routes. Our results indicate that when calculating inhalation equivalent doses of CHCl3, it is critical to include the AUC from the exposure period in addition to the AUC after the end of the exposure period. Thus, studies which measure the concentration of volatile organic compounds in the blood during the inhalation exposure period are crucial. The data reported here makes an important contribution to the physiologically based pharmacokinetic (PBPK) database of CHCl3 in rodents.
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Affiliation(s)
- Makoto Take
- a Japan Bioassay Research Center, Japan Industrial Safety and Health Association , Hadano , Kanagawa , Japan
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Take M, Matsumoto M, Takeuchi T, Haresaku M, Kondo H, Senoh H, Umeda Y, Takamura-Enya T, Fukushima S. Inhalation exposure to 1,2-dichloropropane: Distribution of blood and tissue concentrations of 1,2-dichloropropane in rats during and after exposure. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2014; 49:1341-1348. [PMID: 25072765 DOI: 10.1080/10934529.2014.928193] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The present investigation was undertaken to determine the distribution and accumulation of 1,2-dichloropropane (DCP) in the blood, lung, liver, kidney, and abdominal fat of rats during and after inhalation exposure. Male rats were exposed to 80 or 500 ppm (v/v) DCP vapor for 360 min and the concentrations of DCP in the blood and tissues during the inhalation exposure period and after the end of the exposure period were measured. DCP accumulation in the abdominal fat was much greater than that in the blood and other tissues. Eighteen hours after the end of inhalation exposure, DCP could still be detected in the abdominal fat in the 80-ppm group, and in the blood, liver, kidney, and abdominal fat in the 500-ppm group. Our results are valuable data pertaining to the pharmacokinetics of DCP and to human health risk assessment of exposure to DCP vapor by inhalation.
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Affiliation(s)
- Makoto Take
- a Japan Bioassay Research Center, Japan Industrial Safety and Health Association , Hadano , Kanagawa , Japan
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Sasso AF, Schlosser PM, Kedderis GL, Genter MB, Snawder JE, Li Z, Rieth S, Lipscomb JC. Application of an updated physiologically based pharmacokinetic model for chloroform to evaluate CYP2E1-mediated renal toxicity in rats and mice. Toxicol Sci 2012; 131:360-74. [PMID: 23143927 DOI: 10.1093/toxsci/kfs320] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Physiologically based pharmacokinetic (PBPK) models are tools for interpreting toxicological data and extrapolating observations across species and route of exposure. Chloroform (CHCl(3)) is a chemical for which there are PBPK models available in different species and multiple sites of toxicity. Because chloroform induces toxic effects in the liver and kidneys via production of reactive metabolites, proper characterization of metabolism in these tissues is essential for risk assessment. Although hepatic metabolism of chloroform is adequately described by these models, there is higher uncertainty for renal metabolism due to a lack of species-specific data and direct measurements of renal metabolism. Furthermore, models typically fail to account for regional differences in metabolic capacity within the kidney. Mischaracterization of renal metabolism may have a negligible effect on systemic chloroform levels, but it is anticipated to have a significant impact on the estimated site-specific production of reactive metabolites. In this article, rate parameters for chloroform metabolism in the kidney are revised for rats, mice, and humans. New in vitro data were collected in mice and humans for this purpose and are presented here. The revised PBPK model is used to interpret data of chloroform-induced kidney toxicity in rats and mice exposed via inhalation and drinking water. Benchmark dose (BMD) modeling is used to characterize the dose-response relationship of kidney toxicity markers as a function of PBPK-derived internal kidney dose. Applying the PBPK model, it was also possible to characterize the dose response for a recent data set of rats exposed via multiple routes simultaneously. Consistent BMD modeling results were observed regardless of species or route of exposure.
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Affiliation(s)
- Alan F Sasso
- National Center for Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Washington, DC 20460, USA.
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