Biodegradable Polymers as Drug Delivery Systems

Abstract

Polyanhydrides have been investigated as a biodegradable material used for controlling the release of drugs. Poly1,3-bis(p-carboxyphenoxy) propane:sebacic acid [P(CPP:SA) 20:80] is one of the popular biodegradable polymers for controlling release of drugs as it has a character of surface degradation mechanism. In this thesis P(CPP:SA) 20:80 was synthesised by the melt condensation. The degradation of P(CPP:SA) 20:80 was investigated in vitro by using ¹H-NMR, IR to determine the manners of degrading process in line with molecular weight changes and effects on the microenvironment such as pH. Paclitaxel was selected to be encapsulated into P(CPP:SA) microspheres using PVA and Vitamin E TPGS as emulsifying agents in order to overcome its poor water solubility and maximise its anti-tumor therapeutic potential. The microspheres were characterized in terms of morphology, particle size, drug content, as well as in vitro drug release behavior. Two implantable disks were prepared using P(CPP:SA) 20:80 and paclitaxel; one by pressing the mixture of P(CPP:SA) 20:80 and paclitaxel, the other was prepared by pressing P(CPP:SA) microspheres loaded with paclitaxel. Studies of the drug release from the disks were carried out in vitro.