Nano-Prodrugs Toward Anticancer Drug Delivery

In conventional chemotherapy for cancer, drugs are generally administered in solution. The administered drug diffuses throughout the body and causes adverse effects. Recently, researchers have attempted to efficiently accumulate drug nanoparticles with diameters of less than 200 nm into cancer lesions by taking advantage of a 150–200 nm gap that exists in the vascular endothelium around cancer tissues; however, there are several challenges that remain to be solved, such as the antigenicity of nanocarriers and the small amount of drug that can be loaded onto a single particle. One attempt to overcome these challenges is the use of carrier-free drug nanoparticles composed of only drug molecules. This chapter outlines the latest trends in carrier-free drug nanoparticles, which we refer to as nano-prodrugs.