Malaysian Journal of Pharmaceutical Sciences, Vol. 4, No. 1, 65–81 (2006) REVIEW ARTICLE CONTROLLED DRUG DELIVERY THROUGH MICROENCAPSULATION NIKHIL K. SACHAN 1* , BHUPENDRA SINGH 1 AND K. RAMA RAO 2 1 Department of Pharmaceutical Sciences, Dibrugarh University, Dibrugarh, Assam –786004, India 2 Research Associate, Ranbaxy Research Laboratories, Gurgaon, Haryana –122001, India An appropriately designed controlled release drug delivery system can be a major advance towards solving problems concerning to the targeting of drug to a specific organ or tissue and controlling the rate of drug delivery to the target site. The development of oral controlled release systems has been a challenge to formulation scientist due to their inability to restrain and localize the system at targeted areas of gastrointestinal tract. Microparticulate drug delivery systems are an interesting and promising option when developing an oral controlled release system. The objective of this paper is to take a closer look at microparticles as drug delivery devices for increasing efficiency of drug delivery, improving the release profile and drug targeting. In order to appreciate the application possibilities of microcapsules in drug delivery, some fundamental aspects are briefly reviewed. Keywords: Drug delivery systems, Microcapsules, Controlled release, Microencapsulation INTRODUCTION During the past decades, there has been an increasing interest in optimizing the efficiency of existing drugs through the use of better- designed drug delivery systems. Intensive interdisciplinary research efforts have led to a variety of advanced dosage forms. The majority of these systems are based on polymers that differ in their permeability, rate of dissolution, degree of swelling and erodibility (Khan 2001). An important class of polymer mediated drug delivery systems that are applied for controlled drug delivery is the microcapsules. Microencap- sulation provides the means of converting liquids to solids, of altering colloidal and surface properties, of providing environmental protection and controlling release characteristics or availability of coated materials (Bakan 1986). The recent research has been heavily involved particularly * Corresponding author: Nikhil K. Sachan, e-mail: nikhilsachan_du@yahoo.co.in