ABSTRACT
Today recent advances in the understanding of the pharmacokinetic and pharmacodynamic behaviour of drugs offer a more rational approach to the development of optimal drug delivery systems. Future success in drug delivery research will largely be the result of multidisciplinary efforts. Therapeutic agents that are more efficacious and safe, using an improved drug delivery system, represent both lucrative marketing opportunities for pharmaceutical companies and advancement in the treatment of diseases. An ideally designed drug system delivers a specified amount of drug to a particular target site at an appropriate time and rate as dictated or desired by the etiological and physiological needs of the body. Conventional pharmaceutical dosage forms are incapable of controlling the rate of drug delivery to target sites. As a result the distribution of a drug in non-target tissue and bodily fluids necessitates therapeutic doses that can far exceed the amount required in the target cells; but higher doses often lead to serious adverse issues during treatment. Thus, novel drug delivery systems are carriers which maintain the drug concentration within a therapeutic range for a longer period of time and, in addition, may deliver the content to the site of action. This chapter deals with drug delivery to the circulation system in a controlled manner.
