Ulcerative colitis is an inflammatory condition with ulcerations throughout the colon. The existing remedies have some limitations such as drug inactivation, poor absorption, and adverse reactions. The present study aimed to design novel microsponge formulations to enhance remission of the dexamethasone (as a model pharmaceutical ingredient) in the colon. Microsponges were prepared by using the quasi-emulsion technique. The optimal formulation was selected by applying the design of experiments approach which used methylcellulose (MC) (0.75-2%, w/w), polyvinylalcohol (PVA)(0.5-1%, w/w), and tween 80 (TW80) (1.5-2.5%, w/w). The critical quality attributes were selected as particle size and entrapment efficiency. The particle size and encapsulation efficiency were found as 140.38 ± 9.2 µm and 77.96 ± 3.4 %. After the optimization; morphological, thermal, and physicochemical characterization studies were performed. Ultimately, the optimal formulation was investigated by using the acetic acid-induced ulcerative colitis model in rats. The physicochemical characterization studies confirmed that the formulation components were compatible with each other. The in vitro release mechanisms were fitted to First order kinetics at pH 1.2 (R2:0.9563), and Korsmeyer-Peppas kinetics at pH 4.5 (R2: 0.9877), and pH 6.8 (R2: 0.9706). The medicated microsponges exhibited remarkable recovery compared to the control group of the in vivo ulcerative colitis model (p < 0.05). It could be concluded that microsponges were evaluated as a promising alternative drug delivery system for the management of ulcerative colitis.
Keywords: Bioavailability; Design of experiments; Dexamethasone; Microsponges; Ulcerative colitis.
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