ABSTRACT

Abstract The recent advances made in the pharmaceutical area allowed the improvement of polymeric-controlled drug release systems design, providing thus an enhanced therapeutic efcacy and reduced side effects of a required drug. This chapter presents the factors that must be taken into account before developing controlled release systems, a classication of these systems, and an overview of the release mechanisms. An important aspect consists in the identication and understanding of the involved mechanisms during the drug release process, since usually a combination of different mechanisms is found. Thereafter, as examples of efcient controlled drug release systems obtaining, two types of polymer-based systems are presented: chitosan matrices containing tannic acid and chitosan liposomes containing ketoprofen. The rst type was studied in vitro by evaluating the drug release kinetics, at ∼37°C, in three dissolution media having different pH values (2.0, 5.2, and 9.3). The tannic acid release mechanism from chitosan matrices was

10.1 Introduction .................................................................................................. 160 10.2 Types of Controlled Drug Delivery Systems ................................................ 161 10.3 Mechanisms of Controlled Release .............................................................. 162 10.4 In Vitro Study of Tannic Acid Release Kinetics from Polymer Matrices .... 163

10.4.1 Materials and Methods ..................................................................... 163 10.4.2 Results and Discussions .................................................................... 164 10.4.3 Conclusions ....................................................................................... 165

10.5 In Vivo Study of the Analgesic Effect of Ketoprofen Polymer Liposomes ...... 166 10.5.1 Materials and Methods ..................................................................... 167 10.5.2 Results and Discussions .................................................................... 169 10.5.3 Conclusions ....................................................................................... 172

10.6 Concluding Remarks .................................................................................... 172 References .............................................................................................................. 172

identied by using the Korsmeyer-Peppas model. The second type of controlled drug release system was studied at rst in vitro, and then in vivo in order to assess the ketoprofen analgesic effect on mice nociception. For this, a hot-plate analgesia meter was involved to measure the response latency time after mice paws thermal stimulation.