Design and characterization of dexamethasone loaded microsponges for the management of ulcerative colitis

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.

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Materials

Dexamethasone (DEX) (>99% purity) was acquired from Rapharm (Athens, Greece). Methylcellulose (MC) was supplied by Evonik GmbH (Essen, Germany). Polyvinyl alcohol (PVA), Tween 80 (TW80), dichloromethane, and methanol were purchased from Sigma-Aldrich (Schnelldorf, Germany). All other chemicals and reagents used in the study were of analytical grade.

Samet Özdemir, Burcu Üner, Juste Baranauskaite, Engin Sümer, Ecem Yıldırım, Aylin Yaba, Design and characterization of dexamethasone loaded microsponges for the management of ulcerative colitis, European Journal of Pharmaceutics and Biopharmaceutics, Volume 187, 2023, Pages 34-45, ISSN 0939-6411, https://doi.org/10.1016/j.ejpb.2023.04.007.

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