Modified drug delivery and Role of Polymers

Abstract

Current efforts in the area of drug delivery include the development of targeted delivery in which the drug is only active in the target area of the body (for example, in cancerous tissues) and sustained release formulations in which the drug is released over a period of time in a controlled manner from a formulation. Types of sustained release formulations include liposomes, drug loaded biodegradable microspheres and drug polymer conjugates. There are many drug release mechanisms known, such as matrix swelling, erosion, drug dissolution (re-crystallisation), drug diffusion, drug – polymer interaction, initial drug distribution and particle size distribution (for powdered matrix systems). Polymers are becoming increasingly important in the field of drug delivery. The pharmaceutical applications of polymers range from their use as binders in tablets to viscosity and flow controlling agents in liquids, suspensions and emulsions. Polymers are used as film coatings to disguise the unpleasant taste of a drug, to enhance drug stability and to modify drug release characteristics. A range of materials have been employed to control the release of drugs and other active agents. Now a days polymers are widely used as biomaterials for delivery systems. Controlled Drug Delivery (CDD) occurs when a polymer, whether natural or synthetic, is judiciously combined with a drug or other active agent in such a way that the active agent is released from the material in a predesigned manner. Paper will discuss different methods of drug delivery, role of polymers in that. Recent developments about polymer applications in this field. Paper will also focus on the aspects related to the material characteristics for successfully used in controlled drug delivery formulations.