The aim of this work is to investigate new and classical techniques, methods and formulations for topical and buccal release. All the formulations proposed are based on natural and biocompatible polymer matrices such as gellan gum, scleroglucan and hydroxypropylmethylcellulose. The proposed formulations are tested by in vitro release tests. In fact they represents a valid support and a useful starting point for the realization of a potentially usable in-vivo pharmaceutical formulation that may have commercial utility. The research work is both experimental and theoretical. Each topic presents a more chemical-pharmaceutical part, based on the formulation preparation and release experiments, and a more theoretical-numerical approach that allows a correct interpretation and description of the experimental data obtained. Release from hydrogels and thin films require different modelling approaches. Also the physico-mathematical description of different release experiments (different release devices such as Franz cell, millifluidic device and USP II) requires different theoretical and numerical techniques. The outcome of an accurate model development is of fundamental importance for future design of pharmaceutical formulations with prescribed release properties. In addition the formulations are investigated through rheological, mechanical, thermoanalytic and mucoadhesive tests in order to have a more comprehensive picture of their practical utilization.