Influence of high-methoxylated pectin on retrograded starch/cellulose nanofibers microparticles as a potential strategy for colonic release of 5-ASA in the treatment of inflammatory bowel disease

Abstract

Inflammatory bowel disease (IBD) is a generic term used to describe disorders involving chronic inflammation of the gastrointestinal tract (GIT). 5-Aminosalicylic acid (5-ASA) is considered the first-line treatment for mild to moderate IBD. For 5-ASA to exert pronounced therapeutic effect, it is necessary to avoid its release in the upper portions of the GIT and promote its release in the colonic region, which contributes to a localized treatment with a significant reduction in side effects. The development of systems using polysaccharides biodegradable by the colonic microbiota, such as retrograded starch (RS), has been considered the most reliable way to release drugs in the colon. The RS can be obtained through the retrogradation process in association with pectin (P) which promotes a higher yield in its contents. In addition, the association of RS with cellulose nanofibers (CNF) allows the construction of composite-type systems, reinforced with nanoscale fibers. However, the high aqueous solubility of P has still been associated with the premature release of 5-ASA in the upper portions of the GIT. The use of Ps with a high degree of methoxylation and, therefore, lower solubility, can be considered a rational strategy to overcome this limitation, contributing to both starch retrogradation and targeting of 5-ASA release to the colon.