Oral Delivery of a GI-Stable Apigenin–Cyclodextrin Complex via Pectin-Coated Nanoliposomes In Situ Gel: A DoE-Optimized Targeted Colon Cancer Therapy by Modulating Gut Drug Sensitivity

This study emphasizes overcoming the challenges of targeted drug delivery in colon cancer therapy by developing gastrointestinal (GI) stable, pectin-coated nanoliposomes for the oral delivery of Apigenin-Cyclodextrin Complex as an in situ gel formation. Initially, the formulation was strategically designed using design expert software for formulation optimization. FTIR and XRD studies were conducted to ensure physical compatibility and to confirm the encapsulation of apigenin within the formulation. In process optimization, among all seventeen formulations run tested, PNL (Api-Cy)-13 was identified for the highest drug loading, favourable size dimension of particle with zeta potential, and spherical external morphology through SEM analysis. The metered drug release during an in vitro study for PNL (Api-Cy)-13 was remarkably high (more than 75% of drug availability in the colonic environment, precisely in contrast to only 20% in the gastric phase in a sustained release manner), focused on colon drug targeting as an in situ gel. Furthermore, apigenin release from PNL (Api-Cy)-13 in an ex vivo chick ileum permeability study was observed both in the absence and presence of 1% vancomycin. An incremental apigenin release in the absence of the antibiotic (1% vancomycin) indicated gut microbial-associated and pectinase-mediated drug release. Here, pectin degradation materializes by the colonic microbial environment, which facilitates desirable incremental colonic drug permeation. Finally, an in vitro MTT assay and a competitive flowcytometric cell uptake study with PNL (Api-Cy)-13 using HCT-116 cells proved significant superiority in cytotoxicity profile for apigenin when delivered as an optimized coated nanoliposome in comparison to free apigenin or other non-modified nano-formulation. Also, the inhibition of the cell efflux process was validated by Multidrug Resistance 1 (MDR1) gene regulation. These observations establish an undoubted promise for the novel biopolymer, pectin-based apigenin-cyclodextrin nanoliposomes as targeted therapy in colon cancer with significant in vivo pharmacokinetics and safety profile.