DESIGN AND DEVELOPMENT OF CAPSULAR MOLDED DEVICES FOR MODIFIED RELEASE OF DRUGS

The present work focused on the formulation and manufacturing of modified-release drug delivery systems employing injection molding (IM) technique. IM is based on the injection, under high pressure and temperature, of thermoplastic materials into a mold. The interest in applying IM as well as micromolding (μIM) techniques, commonly used within the plastic industry, in the pharmaceutical field is driven by the possible reduction of development and manufacturing costs related to the simplification of industrial scalability, to the patentability of the new drug products and to the product versatility in terms of size and shape. The PhD research activity was focused on the design and the development of prolonged release drug delivery systems and site specific one, both in the form of capsular devices. A large part of the work was aimed at the setup of methods for the screening of polymeric carriers and composites and on the identification of parameters as well as procedures for the evaluation of hot-processability of materials and physico-technological characterization of molded prototypes. Considering the development of extended release drug delivery systems, the first step was the selection of the most appropriate polymer candidate for evaluating the feasibility of μIM for the manufacturing of capsular containers intended for prolonged release of drug. The following step was the development of an investigation protocol to assess the processability by micromolding of EC-based materials through tests performed on a screening disk, in addition to the performance studies conducted on such molded disk-shaped specimens. As regards the development of site specific drug delivery systems for colon targeting manufactured by µIM, the possibility to combine the time-controlled and the enzyme-triggered approaches was attempted in order to make up for the respective limitations of the individual approaches thus reducing the variability and achieving a fine-tuning of the release performance.