Biopolymers for Parenteral Drug Delivery in Cancer Treatment

Abstract

Traditional chemotherapy treats tumors by systemic treatment via parenteral or oral application, by intratumoral injection, or by interstitial placement of drugs. New drug delivery systems can be used for local delivery to reduce side effects, to improve the bioavailability, or to target specific sites. Most of these specifically designed dosage forms in cancer treatment are based on polymeric materials to control the release of the active agent via dissolution, matrix erosion and degradation, diffusion, or cleavage of prodrugs. The focus of this chapter is on parenteral biodegradable carrier systems, which present a main form of drug delivery or targeting in local or systemic chemotherapy. Enhanced local drug retention at the tumor site can be achieved by administration of drug-loaded monolithic polymer implants of different shapes, microparticles, or a polymeric gel vehicle. In addition, chemoembolization provides higher local therapeutic concentrations. The expression chemoembolization connotes a bipartite anticancer effect through occlusion of the tumor vascular bed via metal coils, ethanol, glues, or particulate systems (1) coupled with cytotoxic drug administration either via embolization followed by chemotherapy or embolization with microparticulate drug delivery systems (2,3). In systemic chemotherapy, biomaterials can also be used for sustained-release formulations that yield steady drug levels and avoid side effects caused by toxic peaks or for dosage forms that allow drugs to selectively lodge in tumors.