Drug Delivery Strategies for the Lower GI Tract: A Review.

The lower gastrointestinal (GI) tract is affected by a range of diseases, including colorectal cancer and inflammatory bowel disease, among others. Effective treatment of these conditions requires drug delivery systems (DDSs) capable of precise targeting. While pH- and enzyme-sensitive DDSs are the most used, they often suffer from premature drug release and target specificity, limiting their efficacy. To address this challenge, researchers are exploring alternative triggers, such as reactive oxygen species (ROS), reduction-oxidation (redox) and modified enzyme- and pH-responsive systems, to enhance specificity and performance. This review highlights the latest advancements and current limitations in targeted drug delivery strategies for the lower GI tract, aiming to improve therapeutic outcomes and the quality of life for patients with intestinal disorders.