This workshop provides an in-depth exploration of PBPK modeling for FIH and DDI applications. Participants will learn how to build, verify, and apply PBPK models across species, handle complex DDI mechanisms, and use simulations to inform study design. The course emphasizes practical skills in navigating PK-Sim and MoBi, incorporating in-vitro data, and evaluating model risk and regulatory applicability. Real-world case studies and guided exercises will reinforce core concepts.