Rose Bengal–Chitosan Nanocomposites for Oral Administration

Rose Bengal (RB) holds promise for therapeutic applications in the gastrointestinal (GI) tract but faces significant limitations due to poor bioavailability and stability in the GI environment. This in vitro proof-of-concept study aimed to develop an oral drug delivery system using self-assembled RB-chitosan (RBCS) nanocomposites formed via electrostatic interactions. RBCS nanocomposites exhibited high drug loading efficiency (87%) and a uniform particle size (~443 nm), with physicochemical analyses confirming molecular interactions and structural stability. However, in vitro studies revealed poor and highly variable drug release in simulated gastric fluids (SGFs), underlining the need for further optimization. To address these limitations, RBCS nanocomposites were encapsulated within well-established alginate beads (AlgBs). Among the tested systems, RBCS20-AlgBs were selected as the optimal one, forming a gastroresistant platform. Encapsulation mitigated burst release, enhanced structural integrity, and enabled sustained RB release under intestinal conditions. Swelling studies demonstrated that RBCS20-AlgBs maintained controlled hydration, preventing premature disintegration. Mathematical modeling indicated a matrix relaxation-driven release mechanism, with RBCS20-AlgBs demonstrating improved reproducibility compared to RB-loaded AlgBs (RB-AlgBs). Future studies should focus on evaluating in vivo performance to confirm the system's efficacy for oral administration.