A Study On A 5-Salicylicacid Colon Specific Delivery Systerm

Colon specific drug delivery has received much interests for the last 20 years .It not only present a possibility of oral administration for therapeutive proteins and peptides, but also has some special advantages for the treatment of local disease such as inflammatory bowel disease( IBD).In present investigation, a new colon specific delivery systerm was developed based on the polysaccharides that can be degraded by the colonic microflora utilizing 5-ASA as the model drug, extrution-spherization and fulid bed technologies were adopted in the delivery systerm preparation.The advancement in colon-specic drug delivery and the athophysiological conditions in the diseased large intestine were reviewed, implications of the conditions on the design of the colon specific delivery systerms were discussed, based on the relative research work available', a new multi-unit delivery systerm was designed, the desired release behavier of the delivery systerm present bimodal drug release pattern, i.e. a minmised drug release in the upper gastrointestinal tract, and a bolus pattern upon entry into the caecum.In the pre-formulation study, the stability of 5-ASA was examined.the soubility of 5-ASA is determined under different pH eviroment.The maximum content of 5-ASA in the core was examined.factors influencing the rate of release were evaluated, including drying method, disintegrating agents content ,the concentration of ethanol in the wetting agents, the relationship between the type of wetting agent and pellet friability was also examined, the formulation of pellets core and process of preparation was decided.