Free open-source Modelica library called Chemical 2.0 (https://github.com/MarekMatejak/Chemical) provides expressions between chemical substances and processes. These robust and unified definitions allow users to choose whether define processes or substances in their dynamic (electro-)chemical models. Propagation of substance definition and chemical solution through connected components simplify configuration. Chemical pathways can start even with unknown substances. Chemical kinetics was rewritten. The possibilities and performance of chemical pathways modeling are increased using a new type of connectors based on inertial electro-chemical potential. Chemical processes can be directly connected without need to add unsignificant states. Parameterization of chemical reactions is also streamlined, e.g. using forward rate and dissociation coefficient.

Mechanistic modeling of drug behavior and response is essential for rational drug development and personalized therapy, yet constructing, maintaining, reusing and customizing complex pharmacokinetic–pharmacodynamic and physiologically based pharmacokinetic models can be error-prone when implemented solely via equations or code. We introduce Pharmacolibrary, a free Modelica library offering standardized acausal components for pharmacokinetics, pharmacodynamics, toxicokinetics/toxicodynamics and pharmacogenomics from compartmental and physiologically based templates to effect models and genotype–phenotype records—to simplify model reuse, customization, and interoperability. Its utility is showcased with gentamicin, midazolam, and fentanyl case studies, including pharmacogenomics-driven clearance adjustments and pharmacodynamics simulations.