High-Payload chitosan microparticles for the colonic delivery of quercetin: Development and in-vivo evaluation in a rabbit colitis model

Quercetin, a natural flavonoid has high potential for management of inflammatory bowel diseases (IBD). However, its onset of action is delayed when administered systemically and high doses are needed for IBD treatment. The present study aimed to develop chitosan microparticles for colonic delivery of clinically relevant quercetin concentrations as a potential treatment for IBD. Different formulations of quercetin microparticles were prepared and evaluated in terms of pharmaceutical, morphological and compatibility aspects. The in vitro release profiles of acid-resistant capsules filled with quercetin microparticles showed that most of quercetin was released in IBD colon simulating medium. Rabbit colitis model was used to evaluate the therapeutic effects of quercetin microparticles based on various assessment criteria (e.g. index of tissue edema, clinical activity score, colon macroscopic and histopathological characteristics, biochemical assays of the levels of myeloperoxidase enzyme and tumor necrosis factor-α and the activities of superoxide dismutase and catalase). The animals treated with quercetin microparticles had significantly improved therapeutic outcomes as compared to those treated with plain drug and the untreated animal controls. The results demonstrate that the developed quercetin microparticles have suitable pharmaceutical properties and might find clinical applications in acute IBD management.