Despite the rapid rise in childhood obesity, a significant knowledge gap remains regarding the impact of obesity on drug pharmacokinetics (PK) in pediatric patients. As a result, this vulnerable population continues to lack access to evidence-based pharmacological treatments. Conducting drug research in children—particularly in specific pediatric subpopulations—poses various challenges. Therefore, regulatory agencies such as the European Medicines Agency (EMA) and the U.S. Food and Drug Administration (FDA) have encouraged the development of animal models. Among these, pigs are particularly noteworthy due to their close anatomical and physiological resemblance to humans, making them an innovative and promising juvenile animal model for reliably predicting PK in children. This project aims to establish a juvenile pig model to investigate how variations in body composition affect the pharmacokinetics of model drugs—namely cefazolin and paracetamol—across different pediatric age groups (2–15 years).