Mesalazine-probiotics beads for acetic acid experimental colitis: formulation and characterization of a promising new therapeutic strategy for ulcerative colitis.

Background: Acetic acid ulcerative colitis (UC) is an experimental condition created due to intra-rectal administration of acetic acid which causes inflammation and ulceration in the lining of colon and rectum. In such condition, the colon cannot absorb liquid from the stools, resulting in larger volume of watery stools. Mesalazine is mainly used for the treatment of UC but suffers from the drawback of having poor bioavailability. UC is also characterized by alteration in colonic microflora. The present work was focused on delivering mesalazine along with probiotic, which would facilitate to refurbish customary growth of microflora. Mesalazine and probiotic were encapsulated in pectin beads with an aim to protect the drug from gastric environment and target to colonic region.

Methods: Pectin beads were prepared, formulation process was optimized for polymer concentration, drug concentration, cross-linking agent concentration. Formulation was characterized for surface morphology, in vitro drug release studies, determination of viable cell count, in vivo ulcer protective studies and stability studies.

Results: Average particle diameter of beads was ∼1.44-1.72 mm. Drug entrapment efficiency was found to be optimal (78-79%). A sustained release of drug was observed for 5 h; nearly 60% of drug was released at the end of 10 h. Microbiological studies of probiotic showed best cell viability. In acetic acid induced UC model, Mesalazine-probiotic beads-treated group showed significant (p < 0.01) ulcer protection index with respect to free drug-treated group.

Conclusion: In conclusion, mesalazine-probiotic loaded beads may serve as a useful colon specific drug delivery system for treatment of colitis.