IJPCBS 2013, 3(1), 150-167 Pramod Kumar Biswal et al. ISSN: 2249-9504 150 I NTERNATI ONAL JOURNAL OF PHARMACEUTI CAL, CHEMI CAL AND BI OLOGI CAL SCI ENCES Available online at www.ijpcbs.com DESI GN AND EVOLUTI ON OF COLON SPECI FI C DRUG DELIVERY SYSTEM Pramod Kumar Biswal*, Anant Kumar 1 and Anupam Singh Bhadouriya 2 1 R.K.D.F School of Pharmaceutical Sciences, Bhopal, Madhya Pradesh, India. 2 Kunwar HariBans Singh college of Pharmacy, Jaunpur, Uttar Pradesh, India. INTRODUCTION In the past two decades, the pharmaceutical scientists are extensively investigated in the area of colonic region for targeted drug delivery system. Targeted drug delivery to the colon is mainly for the treatment of colonic diseases, for drugs like proteins and peptides, for the treatment of diseases sensitive to circadian rhythms such as Asthma, Angina and Rheumatoid arthritis and for delivery of steroids, which absorbable in colon. The advent of slow release technologies increase the chances for a drug to be released in the colon and thus this organ has an important role to play in drug absorption from oral sustained release formulations. In 1942, Svar t z discovered that sulfasalazine; the sulfanilamide prodrug of 5- aminosalicylicacid (5-ASA) is effective in the treatment of rheumatoid arthritis and anti-inflammatory disease. The exact mode by which the drug target itself to the colon was elucidated much latter in 1970 i.e., colon specific azoreductase splits sulfasalazine causing the release of the active moiety 5-aminosalicylicacid. After the sever al other azo-bonds containing compounds designed to locally r elease 5-aminosalicylicacid w er e synthesized bensalazine, balsalazide and olsalazine. In1986, Saffron and coworkers described the use of azo containing acrylic polymers to the delivery of protein drugs like insulin to the colon (Girish et al. 2006). Review Article ABSTRACT Due to greater flexibility in design of dosage form and high patient compatibility, oral administration of different dosage forms is the most commonly used method.But the gastrointestinal tract presents several formidable barriers to drug delivery. In oral colon-specific drug delivery system, colon has a large amount of lymphoma tissue which facilitates direct absorption in to the blood, negligible brush boarder membrane activity, and much less pancreatic enzymatic activity as compared with the small intestine. Colon-specific drug delivery has gained increased importance not just for the delivery of the drugs for treatment of local diseases associated with the colon but also for its potential for the delivery of proteins and therapeutic peptides. Different approaches are designed based on pro-drug formulation, pH- sensitivity, time-dependency (lag time), microbial degradation and osmotic pressure etc. to formulate the different dosage forms like tablets, capsules, multi-particulates, microspheres, liposomes for colon targeting. The efficiency of drug delivery system is evaluated using different in vitro and in vivo release studies. This review updated the research on different approaches for formulation and evaluation of colon-specific drug delivery systems (CDDS). Key words: Colon specific drug delivery system, Microbial degradation, Osmotic Pressure.