From this simplified schematic of DDS processing and drug release, it becomes apparent that a critical step in the pharmacodynamics of drugs loaded into DDS is the release from the particle. For most delivery systems, drug release is optimally slow in the circulation and rapid inside of target cells.
dose to drug effect. 1-5. Drug pharmacodynamics are affected by the drug concentration at the site of the receptor, density of receptors on the target cell surface, mechanism by which a signal is transmitted into the cell by sec-ond messengers, and regulatory factors that control gene translation and protein production.
It goes without saying that the goal of pharmacodynamics in a pharmacological therapy setting is to exert positive effects at the least necessary dose that produces the maximum therapeutic effect while minimizing the pharmacodynamics that leads to an adverse event.
With this level of knowledge, the best-case scenario for describing pharmacodynamics would be to link an estimated total or receptor-bound target tissue concentration to a therapeutic outcome using a signal transduction model ( Sun and Jusko, 1998; Mager and Jusko, 2001b; Lobo and Balthasar, 2002 ).