Preclinical Evaluation of Nanocarriers: In Vitro, Ex vivo, and In vivo Models

The preclinical assessment of nanocarriers represents a vital stage in the creation of innovative drug delivery systems, ensuring their safety, effectiveness, and potential for translation into human clinical trials. This chapter explores the three main preclinical testing methods: in vitro, ex vivo, and in vivo, each providing unique benefits for evaluating the pharmacokinetic and pharmacodynamic properties of nanocarrier formulations. In vitro models, which include 2D cell cultures, co-culture systems, and sophisticated 3D spheroids or organoids, offer controlled settings for examining cytotoxicity, cellular uptake, and drug release kinetics. Ex vivo models, such as isolated perfused organs, excised tissues, and organ-on-chip platforms, serve as a link between cell culture and whole-animal studies by maintaining physiological structure and function, facilitating localized toxicity and penetration assessments. In vivo models, which involve both rodent and non-rodent species, allow for a thorough evaluation of biodistribution, metabolism, immunogenicity, and therapeutic effectiveness within a systemic framework. Particular attention is given to the selection of animal models based on the type of disease and the characteristics of the nanocarrier. The chapter also emphasizes the importance of imaging technologies (fluorescence, PET, MRI) and biomarkers for real-time monitoring and the development of predictive modeling systems. Furthermore, it addresses regulatory considerations and ethical issues, along with emerging trends in preclinical personalized models, such as patient-derived xenografts and humanized animals. These preclinical strategies provide the basis for the optimization of nanocarrier design and translation in clinical applications.