Shifting Perspectives on Biotherapeutic Treatment in Ulcerative Colitis using Lipid Mesophases: Formulation Design and Preclinical Validation

Biotherapeutics are required to achieve high remission rates in patients with severe ulcerative colitis (UC); however, adverse effects, complex dosing regimens, administration routes, and low patient compliance may limit their widespread clinical use. Given the localized nature of UC, this study aimed to develop and evaluate a localized delivery strategy for infliximab (IFX), an anti-tumor necrosis factor- (TNF-) monoclonal antibody (mAb) recommended by the European Crohns and Colitis Organization (ECCO) and the American Crohns & Colitis Foundation for moderately-to-severely active UC. Exploiting the intrinsic biocompatibility, mucoadhesivity, and protein-entrapment capacity of lipid mesophases (LMPs), IFX was encapsulated within the gel matrix, providing protection against enzymatic and environmental degradation. IFX-loaded LMPs were designed for targeted delivery to inflamed colonic tissues via rectal or oral administration, with patient-centric oral dosage forms manufactured using a 3D printing approach. A comprehensive physicochemical characterization was performed to elucidate mesophase self-assembly and its relationship with IFX release profiles in biorelevant fluids. Therapeutic efficacy was evaluated in vivo using a dextran sulfate sodium (DSS)-induced colitis rat model, which demonstrated rectal gel retention for at least 8 h and colonic targeting of the oral formulation within 6 h. Under severe inflammatory conditions, LMP-based formulations reduced disease activity, inflammatory biomarkers (TNF- and fecal lactoferrin), and colon shortening to values comparable to those of healthy controls, outperforming the therapeutic efficacy of subcutaneous IFX. Overall, this study establishes a biocompatible delivery platform that enables targeted colonic IFX release and suppresses systemic absorption, representing a promising advancement in the biotherapeutic treatment of UC.