Nanoscale particulate systems for multidrug delivery: towards improved combination chemotherapy.

While combination chemotherapy has led to measurable improvements in cancer treatment outcomes, its full potential remains to be realized. Nanoscale particles such as liposomes, nanoparticles and polymer micelles have been shown to increase delivery to the tumor site while bypassing many drug resistance mechanisms that limit the effectiveness of conventional therapies. Recent efforts in drug delivery have focused on coordinated, controlled delivery of multiple anticancer agents encapsulated within a single particle system. In this review, we analyze recent progress made in multidrug delivery in three main areas of interest: co-delivery of antineoplastic agents with drug sensitizers, sequential delivery via temporal release particles and simultaneous delivery of multiple agents. Future directions of the field, in light of recent advances with molecularly targeted agents, are suggested and discussed.