ABSTRACT
Drug vehiculization capability (loading and release properties) determines the performance of drug delivery systems. Entrapment or conjugation of an active agent to a polymeric system may protect the drug molecules from inactivation and help to store its activity for prolonged durations, decrease its toxicity as well as may achieve administration fl exibility. Drug release is the reverse process by which drug molecules are liberated from the solid phase, and become available for absorption and pharmacological action. Thus, drug loading and release are related to each other because they depend on the physical chemistry of both the matrix and the drug, and on the interaction between the matrix, the drug and the environment. An adequate engineering of a polymer-based nanoparticulate drug delivery system further relies on the pharmacokinetic and biodistribution profi les, and on the transition process from blood to the tissue/organ. The administration route may play a decisive role in the development of the therapeutic activity.
