Colon-Targeted Curcumin Delivery Systems: Mucoadhesive Approaches, Challenges, and Emerging Multi-Mechanistic Strategies

Abstract

Curcumin possesses excellent properties associated with inflammation, oxidative stress, and cancer. This makes it a potential therapeutic agent for treating inflammatory bowel diseases (IBDs) and colorectal cancers (CRC). Limitations on the clinical use of curcumin include: its poor solubility in water, its inability to be absorbed by the gut, rapid metabolism, and lack of stability in the GI tract. Therefore, colon-targeted drug delivery systems (CTDDS) are being used to improve the targeted delivery of curcumin at the site of action, as well as to reduce the premature release of curcumin before it reaches the colon. Various strategies have been explored for CTDDS, including pH-dependent, time-dependent, enzyme-responsive, pressure-dependent, and mucoadhesive systems. Additionally, most research geared to finding new CTDDS focuses on the use of multifunctional systems with multiple targeting mechanisms (e.g. mucoadhesion, enzymatic activation, and ROS-sensitive release) to maximize the therapeutic effect and colonic specificity of the drug. This paper reviews the pharmacological significance of curcumin in colonic disorders, difficulties related to its oral administration, main strategies for targeting the colon, as well as recent advances in developing multifunctional delivery systems aimed at enhancing curcumin's use in colonic disease therapy.