Publication Ref No.: IJPRD/2011/PUB/ARTI/VOV-3/ISSUE-1/MARCH/014 ISSN 0974 – 9446 International Journal of Pharma Research and Development – Online www.ijprd.com 134 NEED OF COLON SPECIFIC DRUG DELIVERY SYSTEM: REVIEW ON PRIMARY AND NOVEL APPROACHES Tarak Jayraj Mehta 1* , Mr A.D.Patel 2 , Dr Mukesh R.Patel 2 ,Dr N.M.Patel 2 1 Reseach Scholar Jjt University, Rajasthan 2 Shree B.M.Shah College of Pharm. Edu. & Research.,Modasa ,Gujarat India. Email:tarakjmehta@yahoo.com ABSTRACT Drug targeting is delivery of drug to receptor, organ or to any other specific part of body exclusively. Various non-magnetic micro-carriers like liposome’s, nano-particles, microspheres, micro-particles are successfully utilized for drug targeting but it seemed to have poor specificity and rapidly cleared off by RES (Reticulo-Endothelial System) under normal circumstances. Magnetism plays a very important role in this case. The field of magnetic micro sphere was pioneered in US by Dr. Kenneth Widder and his colleagues in late 1970’s. Magnetic field is believed to be harmless to biological system and adaptable to any part of body. Up to 60% of an injected dose can be deposited and released in controlled manner in selected surface. After administration of that formulated drug place a magnet on body site where one need action. Due to magnetic property drug, get attracted to that site either via enzymatic activity or changes in physiological condition like pH, osmolality, temperature and be taken up by tumour cells. It is a challenging area for future research and holds lots of promises for novel and efficient approach for targeted drug delivery system. This review focuses on drug targeting by Magnetic Microspheres, various magnetic carriers and their characterization. Key Words: colonic delivery system, time- controlled systems, , osmotic-controlled systems, timed- release systems, INTRODUCTION Oral controlled - release formulations for the small intestine and colon have received considerable attention in the past 25 years for a variety of reasons including pharmaceutical superiority and clinical benefits derived from the drug - release pattern that are not achieved with traditional immediate (or) sustained - release products 1 . Tarak Mehta