The course aims to provide appropriate information about the current legislation that regulates the development of experimental projects / protocols that involve the use of animals, emphasizing the importance of the 3Rs, defined as Refinement (evaluation damage and optimization of methods to reduce suffering), Reduction (use of the minimum number of animals to give statistical validity to the experimental data) and Replacement (replacement of tests on animals with in vitro tests). The course will focus on the alternative methods already validated, in prevalidation or in development phase, including the use of isolated organs, cells confluent monolayer and reconstituted tissues. Commercial reconstituted tissue models will be taken into account, in terms of anatomical and physiological characteristics, the type of study (irritation, corrosion, absorption, drug delivery, inflammation, etc.) in combination with the product to be tested (single active principle /excipient and/or full formulation) depending on the field of application such as pharmaco-toxicological, cosmetic or medical device. A part of the course will focus on the computational methodologies for "drug repurposing/repositioning" and a branch of computational pharmacology, namely, Quantitative System Pharmacology (QSP), that has been emerging will be treated. Using QSP is possible to evaluate the potential pharmacological profile of a drug candidate related to the pathophysiological mechanisms of a disease.