Stimuli-Responsive Alginate-Based Micro- and Nanocarriers for Colon-Targeted Drug Delivery in Inflammatory Bowel Disease and Colorectal Cancer: A Systematic Review

Abstract Inflammatory bowel disease (IBD) and colorectal cancer (CRC) pose significant global clinical burdens, where traditional systemic treatments are often limited by adverse effects and low site-specificity. Alginate, a biocompatible natural polysaccharide, has emerged as a cornerstone for colon-targeted drug delivery systems (CDDS) due to its pH-responsive gelation and protective properties. This PRISMA 2020-compliant systematic review evaluates 34 studies on stimuli-responsive alginate-based micro- and nanocarriers. Systematic searches (PubMed, Scopus, Web of Science, ScienceDirect; 10 January 2025) identified 2,847 records; after duplicate removal and screening, 34 studies met eligibility criteria. Dual-mechanism systems (pH-sensitive coatings + enzyme-triggered cores) restricted premature release to 80% colonic release and significantly improved body-weight recovery, colon length, and cytokine suppression (TNF-α, IL-6) in murine models. Alginate-chitosan complexes enhanced mucoadhesion and probiotic viability. These systems offer a potent, biocompatible alternative to conventional therapies by improving regiospecificity and protecting sensitive cargo.