ABSTRACT

This chapter describes an approach to creating degradable polymeric nanospheres that, to a large extent, display the desired features of long-circulating drug carriers. The development of injectable drug-loaded carriers with blood circulation times long enough to continuously deliver drugs, imaging agents, or other molecules, to specific sites in the body has been a major challenge. The efficacy of Poly(ethylene glycol) (PEG)-coated nanoparticles in avoiding opsonization can be determined by incubating samples with plasma proteins, then measuring the nature and the amount of the adsorbed proteins. One of the goals of PEG-coated nanospheres is to achieve drug-loaded carriers, able to liberate the active compound in a controlled manner directly into the bloodstream. Drug release and polymer degradation are two interconnected phenomena. Poly(ethylene glycol)-coated nanospheres are a promising new system that has potential for intravenous drug administration. The nanospheres’ hydrodynamic diameter and size distribution can be measured by quasi-elastic light scattering, also called photon correlation spectroscopy.