Advances in delivery of Irinotecan (CPT-11) active metabolite 7-ethyl-10-hydroxycamptothecin.

CPT-11 is a first-line chemotherapy for advanced or metastatic colorectal cancers. 7-Ethyl-10-hydroxycamptothecin (SN38), the active metabolite of CPT-11, has an anticancer efficacy 100-1000 folds more than CPT-11 in vitro. However, the drawbacks such as ultralow solubility and poor stability, greatly limit the clinical applications of SN38. Recently, SN38-based nanomedicines have greatly improved the pharmaceutical and therapeutic characteristics of SN38. In addition, these nanosized delivery systems can target tumor tissues via the EPR effect and/or active-targeting strategies, thereby significantly improving anticancer efficacy, reducing side effects and reversing drug resistance. This review focuses on the advances of nano-delivery systems for SN38. We categorize the published studies into two groups, physical encapsulation and chemical conjugation, for the development of SN38 nano-delivery systems, and particularly summarize those for active tumor targeting. The advantages and shortcomings of current SN38 nano-delivery systems, aiming to develop more potent SN38 nano-delivery systems, are also discussed.