Strategies and opportunities of micro/nano delivery systems for targeted therapy of ulcerative colitis: Focus on underlying mechanisms and future perspectives

Ulcerative colitis (UC) is a common progressive inflammatory disease whose incidence has increased rapidly in recent years, and can develop into colorectal cancer in severe cases. There are currently no adequate or effective treatments for UC due to the fact that some patients have found suboptimal results after repeated administration, while others have experienced adverse effects. With the rapid development of nanotechnology, developing innovative colon-targeting platforms is essential to improving efficacy, reducing side effects, and improving patient compliance. In this review, we summarize the pathophysiological characteristics of UC and the most recent status of numerous nanodrug delivery systems based on different targeting mechanisms in treating UC. Oral, intravenous, and rectal drug delivery nanoparticles targeting the colon are discussed, which can provide ideas for the design of colon-targeting nanoparticles for the treatment of colon diseases, especially for the treatment of UC. Last but not least, we provide a glimpse into the future of colon-targeted delivery systems, as well as future advancements in the field.