Recent Advances in Designing 5-Fluorouracil Delivery Systems: A Stepping Stone in the Safe Treatment of Colorectal Cancer.

5-Fluorouracil (5-FU) has become one of the most widely employed antimetabolite chemotherapeutic agents in recent decades. It is considered a first line antineoplastic agent for the treatment of colorectal cancer. Unfortunately, chemotherapy with 5-FU has several limitations, including its short half-life, high cytotoxicity and low bioavailability. In order to overcome the drawbacks of 5-FU and enhance its therapeutic efficiency, many scientific groups have focused on designing a new delivery system to successfully deliver 5-FU to tumor sites. We provide a comprehensive review on different strategies to design effective delivery systems, including nanoformulations, drug-conjugate formulations and other strategies for the delivery of 5-FU to colorectal cancer. Furthermore, co-delivery of 5-FU with other therapeutics is discussed. This review critically highlights the recent innovations in and literature on various types of carrier system for 5-FU.