Factors affecting delivery of antiviral drugs to the brain.
Although the CNS is in part protected from peripheral insults by the blood-brain barrier and the blood-cerebrospinal fluid barrier, a number of human viruses gain access to the brain, replicate within this organ, or sustain latent infection. The efficacy of antiviral drugs towards the cerebral viral load is often limited as both blood-brain interfaces impede their cerebral distribution. For polar compounds, the major factor restricting their entry lies in the tight junctions that occlude the paracellular pathway across these barriers. For compounds with more favourable lipid solubility properties, CNS penetration will be function of a number of physicochemical factors that include the degree of lipophilicity, size and ability to bind to protein or red blood cells, as well as other factors inherent to the vascular and choroidal systems, such as the local cerebral blood flow and the surface area available for exchange. In addition, influx and efflux transport systems, or metabolic processes active in both capillary endothelial cells and choroid plexus epithelial cells, can greatly change the bioavailability of a drug in one or several compartments of the CNS. The relative importance of these various factors with respect to the CNS delivery of the different classes of antiviral drugs is illustrated and discussed.
Strazielle
Nathalie
N
INSERM U433 Faculté de Médecine RTH Laennec, IFR 19, Lyon France. strazielle@lyon.inserm.fr
Ghersi-Egea
Jean-François
JF
D000998:Antiviral Agents / Q000008:administration & dosage* / Q000134:cerebrospinal fluid / Q000493:pharmacokinetics; D001682:Biological Availability; D001693:Biological Transport, Active; D001812:Blood-Brain Barrier; D001921:Brain / Q000187:drug effects* / Q000378:metabolism / Q000821:virology; D001927:Brain Diseases / Q000134:cerebrospinal fluid / Q000188:drug therapy / Q000378:metabolism; D016503:Drug Delivery Systems; D006801:Humans; D014777:Virus Diseases / Q000134:cerebrospinal fluid / Q000188:drug therapy / Q000378:metabolism
D000998:Antiviral Agents