Stimuli sensitive systems for camptothecin delivery

Abstract Camptothecin (CPT) is a water insoluble alkaloid isolated from Camptotheca acuminate , which shows strong antitumor activity against a wide spectrum of human cancers. Unfortunately, its poor water solubility, low stability at physiological pH, reversibility of drug–target interaction and severe systemic toxicities, are strong issues that preclude its use at the clinical stage. To overcome CPT’s limitations, many drug delivery systems (DDSs) have been formulated and are being investigated to improve its pharmaceutical profile. Here, stimuli-responsive DDSs show several attractive features in medical and pharmaceutical fields. Their most important characteristic is the ability to deliver to target cells a therapeutic agent with no zero premature release, as a result of an accurately controlled release process through a specific intracellular stimulus or external input, which minimizes undesired side effects. Typical stimuli are pH, redox potential, electric field, magnetic fields, ultrasounds, temperature, osmotic pressure, enzyme activity, and light. In this chapter, we aim to summarize the most advanced achievements in the design, development, and synthesis of CPT stimuli-responsive DDSs, including some remarks on the most important formulations currently under clinical trials.