FORMULATION, DEVELOPMENT AND EVALUATION OF COLON TARGETED BEADS FOR ANTI-INFLAMMATORY DRUG

Mesalamine is an anti-inflammatory drug used in treatment of Crohn’sdisease and ulcerative-colitis. Since Mesalamine islargely absorbed from the upper intestine, selective delivery of drugs into the colon may be regarded as a better method of drug delivery with fewer side effects and a higher efficacy.An objective of the present investigation is to prepare and evaluate Mesalamine microbeads for colon targeting. These microbeads were prepared by Ionotropic gelation method using physical mixtures of gellan gum locust bean gum and sodium alginate in ratio 1:3:2, 1:1:2 and 3:1:2. Eudragitcoated Mesalamine microspheres were evaluated for surface morphology, particle size analysis, percentage drug entrapment, percentage yield and in vitro drug, in-vivo drug release and stability studies. Drug release studies carried out in SGF (pH 1.2) for 2hrs, SIF (pH 6.5) for 5 hrs, SCF (pH 7.4) for 24hrs. The cumulative percent drug release after 24 hrs was found to 96.73%; 89.76%; 86.12% and 82.12%, 74.79%, 68.24% for F-1, F-2, F-3 of uncoated and CF1, CF2, CF3 of coated formulation respectively. By comparing the in vitro release pattern of all coated and uncoated formulations, it was found that the drug release from coated formulations was prolonged than uncoated beads. The drug release may be mainly controlled by drug diffusion through the natural gums matrix. The in vivo release performance of the developed colon specific formulation was carried out by gamma scintigraphy.The scintigraphy of the optimized formulation CF3 (92 ± 0.8% Radio labeling efficiency) was performed using rabbits (animal model) in order to establish its colon targeting potential. Scintigram shows the residence of beads in colon more than 12 hrs. These results showed that Eudragit S-100 coated beads formulation may be useful for targeting mesalamine to the colon. Stability studies indicated that the optimized formulation does not show any significant change with respect to shape, color, surface and in vitro drug release.It is concluded from the present investigation that Mesalamine microspheres are promising controlled release carriers for colon-targeted drug delivery.