Colon targeted drug delivery system

In the recent year colonic drug delivery has gained importance for delivery of drug for the treatment of local diseases associated with colon and systemic delivery of therapeutic peptides and proteins. Treatment could be more effective if it is possible for drug to be directly delivered to colon. During the last decade there are new developments in site-specific formulations for targeting drug to the colon. Colon has proved to be a site for the absorption of poorly soluble drugs. Micro carriers as colon drug delivery System has gained importance for the delivery of the drug in the colon because of their increase biocompatibility, controlled release of drug and higher stability. This review is discusses in brief about introduction to colon, Micro Carrier as colon drug delivery system. Oral delivery is still the most favorable route of drug administration, especially for chronic therapies where repeated administration of drug is required. Oral administration offers less pain, good patient convenience and reduced risk of cross infection and needle stick injuries.

Colon targeted drug delivery system is capable of protecting the drug in route to the colon i.e. drug gets released and absorbed once it reaches the colon. A multiparticulate system combining pH sensitive property and biodegradability has been investigated to prepare and evaluate Eudragit S-100 coated Sodium alginate microspheres for colon targeting of Tramadol Hydrochloride. Uncoated Tramadol Hydrochloride microspheres were prepared by ionotropic gelation technique using different ratios of Tramadol Hydrochloride and Sodium alginate. Coated Tramadol Hydrochloride microspheres were prepared by coacervation phase separation technique using different ratios of uncoated Tramadol Hydrochloride and Eudragit S-100/ Eudragit L-100. Uncoated and coated Tramadol Hydrochloride microspheres were evaluated for percentage yield, particle size, surface morphology, flow properties, drug content and entrapment efficiency and were found to be within the acceptable range. The uncoated microspheres sustained the release upto 8 hrs whereas coated microspheres sustained the release upto 12 hrs in a pH progression medium mimicking the condition of GIT. The drug release from MC4 formulation coated with Eudragit S-100 (1:4) showed desired rate as there was no drug release observed upto 4-5 hrs, while in colonic fluid controlled drug release was observed releasing about 69.66 % after 12 hrs. The release kinetics followed Peppas showing Super Case II transport. Stability studies suggested formulations were stable. It is concluded from the present investigation that Eudragit S-100 coated Sodium alginate microspheres are promising controlled release carriers for colon targeted delivery of Tramadol Hydrochloride.