Biopolymeric advanced hydrogel systems with special reference to pectin for targeted colonic drug delivery: A review.

Colonic diseases, including Inflammatory Bowel Disease (IBD) and Colorectal Cancer (CRC), are escalating global health concerns. In 2020, CRC ranked as the second leading cause of cancer related deaths, with over 1.9 million new cases worldwide. India reported over 64,000 CRC cases in 2022, with projections suggesting a doubling of incidence and mortality by 2050, driven by lifestyle changes, urbanization, and rising IBD prevalence. These trends highlight the need for enhanced prevention, early detection, and targeted therapies. Conventional oral drug delivery faces challenges due to physiological barriers and nonspecific drug distribution, limiting efficacy for colon-specific treatments. Colon-targeted drug delivery systems leverage physiological triggers like pH, transit time, and microbial activity to achieve site specific release. Among these, hydrogels, particularly those based on natural biopolymers, are promising due to their biocompatibility, tunable properties, and ability to mimic natural tissues. Their porous, water retaining structure enables sustained and localized drug release. Natural polymers such as pectin, alginate, chitosan, guar gum, and starch are favored for their safety and biodegradability. Pectin excels due to its stability in acidic environments, resistance to upper GI tract enzymes, and degradation by colonic microbiota. It forms gels with divalent cations and adapts to pH changes, making it ideal for colon-targeted drug delivery. This review explores current challenges, delivery mechanisms, and advanced hydrogel-based systems, emphasizing pectin-based carriers, and outlines future strategies to improve therapeutic outcomes for CRC and IBD management.