Characteristics of lipid-based formulations that influence their biological behavior in the plasma of patients.

Patients with cancer and infectious diseases often have changes in the composition and concentration of their different blood components. These changes include variations in the composition and concentration of plasma lipoprotein lipids, in transfer rates of endogenous lipid between different lipoprotein classes, and in concentrations of phagocytic cells (i.e., monocytes and macrophages). It appears that the interaction of many lipid-based drug formulations with plasma lipoproteins and blood phagocytic cells may be responsible for the unpredictable pharmacokinetics and pharmacodynamics of those compounds when administered to patients with diseases. This review examines the potential mechanisms that may explain the biological behavior of lipid-based drug formulations used in the treatment of infectious diseases and cancer.