Activation approaches on delivery of imaging and therapeutic agents

Abstract

Successful treatment for a disease relies upon the effective delivery of a therapeutic agent to the target site. An approach to enhance the therapeutic efficacy and to minimize unwanted side effects is to formulate a drug carrier for active and passive targeting. Alternatively, activatable agents have been designed to release active pharmaceutical moieties in response to internal (pH and enzyme) or external (heat, light, and magnetic field) stimuli. Often, the drug releases from these agents are self-regulatory or are remotely controlled in a spatial and/or temporal manner. A site-specific drug release can also improve the therapeutic efficacy, decrease the side effect, and reduce dosage regimen. Complementary to nanotechnology, activatable agents with various built-in sophisticated mechanisms have recently been engineered. Some of them have been used for the development of contrast agents to reduce the imaging background. This chapter provides an update review of activatable agents, with specific examples being highlighted to illustrate their mechanisms and potential applications for imaging and the treatment for diseases, such as cancer.