This protocol assumes an intermediate level of scientific competency with regard to techniques, instrumentation, and safety procedures. Rudimentary assay details have been omitted for the sake of brevity. NCL Method GTA - 13

Characterization of drug release under physiological conditions is very important for prediction of drug release in vivo, and can be used for formulation optimization. This assay uses a blood partitioning technique to measure the release of free drug from a nanoparticle-encapsulated drug complex. This assay is based on the principle that the free drug will partition between the plasma andred blood cell (RBC)fractions, whereas the hydrophilic nanoparticle platform is generally retained in the plasma fraction.