Pharmacokinetics, Toxicological risk assessment, Mathematical modeling, Uncertainty analysis, Model validation
AuthorsAbstractMathematical modeling has become an essential component of modern pharmacokinetics and toxicological risk assessment, offering systematic tools to describe, predict, and interpret the behavior of chemical substances within biological systems. This study presents a comprehensive and integrative examination of mathematical approaches used to characterize exposure dynamics, biological responses, and adverse outcomes across pharmaceutical and toxicological contexts. The work synthesizes deterministic and probabilistic pharmacokinetic frameworks, population-based modeling strategies, and quantitative toxicological risk assessment methods, with particular emphasis on their integration through coupled pharmacokinetic– toxicodynamic modeling. By incorporating sensitivity analysis, uncertainty quantification, and structured model validation, the study highlights how mathematical rigor enhances the credibility, transparency, and predictive reliability of risk estimates. The analysis demonstrates that dynamic and uncertainty-aware models provide significant advantages over traditional static and deterministic approaches by explicitly addressing variability, nonlinear behavior, and time-dependent effects. These modeling frameworks support more informed decision-making in drug development, safety evaluation, and regulatory science. The study further underscores the importance of adopting fit-for-purpose modeling strategies and standardized validation practices to ensure robust application in real-world scenarios. Overall, the findings emphasize that integrated mathematical approaches represent a critical pathway toward more accurate, biologically meaningful, and defensible pharmacokinetic and toxicological risk assessments. 1. IntroductionThe fundamental component of the modern drug development and chemical safety assessment is the risk assessment in pharmacokinetics and toxicology. Pharmacokinetics tries to mathematically simulate absorption, distribution, metabolism and excretion of compounds in the body, and toxicological risk assessment tries to make estimations on the likelihood and severity of adverse effects of exposure to chemicals. During the past 20 years, the two disciplines have been growing in their connection to each other through the modelinformed drug development (MIDD) paradigm, which concentrates on quantitative models to assist in decision-making during the drug lifecycle (Bhat et al., 2025). This shift reflects an appreciation of the growing inadequacy of conventional empirical approaches to deal with the complexity, uncertainty and variability of biological systems and human populations. The use of pharmacometric modeling has made a great contribution to regulatory science and research in pharmaceuticals. Simulation-based approaches have lately gained relevance in dose choice, trial optimization, benefit-risk evaluation, and post-marketing studies (Madabushi et al., 2022). The effectiveness of quantitative decision-making has also been enhanced through the collaborative structures involving the integration of mathematical models of industry, academia, and regulatory agencies (Anziano and Milligan, 2020). The current development indicates that pharmacometrics ceased to be a supportive analysis tool and became a key element of strategic drug development, with applications in the case of small molecules, biologics, and complex therapeutic modalities (Xiong et al., 2025). •••••••••••••••••••••••••••••••• ejprd.org- Published by Riset Publishing Services LLC.
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