Dynamic in vitro modeling of the blood-brain barrier:: a novel tool for studies of drug delivery to the brain

Apart from in exceptional and rare circumstances when drugs may be inserted directly into the CNS, it is often difficult to achieve therapeutically relevant dosages in the brain. This is because oral or parenteral administration effectively results in the exclusion of most drugs by the blood-brain barrier (BBB). Therefore, it is important to develop systems that allow for rapid and inexpensive determination of the BBB-permeability properties of novel therapeutic drugs. Recent advances allow for the manipulation of brain transport of drugs by chemical facilitation with lipophylic compounds or viral vectors. Studies performed on viable in vitro models are set to accelerate the design of drugs that selectively and aggressively target the CNS.