title: [The blood-brain barrier and drug delivery in the central nervous system].
abstract: OBJECTIVE
  To provide an updated view of the difficulties due to barriers and strategies used to allow the release of drugs in the central nervous system.
  
  
  BACKGROUND
  The difficulty for the treatment of many diseases of the central nervous system, through the use of intra-venous drugs, is due to the presence of barriers that prevent the release of the same: the blood-brain barrier, blood-cerebro-spinal fluid barrier and the blood-arachnoid barrier.
  
  
  METHODS
  The blood-brain barrier is the main barrier for the transport of drugs in the brain that also acts as a immunologic and metabolic barrier. The endothelial cells of the blood-brain barrier are connected to a junction complex through the interaction of transmembrane proteins that protrude from de inside to the outside, forming a connection between the endothelial cells. The transport of substances to the brain depends on the mechanisms of transport present in the barrier and the diffusion of these compounds also depends on the physicochemical characteristics of the molecule. Some diseases alter the permeability of the blood-brain barrier and thus the passage of drugs. Strategies such as the use of methods for drug delivery in the brain have been investigated.
  
  
  CONCLUSIONS
  Further details regarding the mechanisms of transport across the blood-brain barrier and the changes in neuropathology would provide important information about the etiology of diseases and lead to better therapeutic strategies.
authors.affiliation: Universidad Federal de Santa Catarina, Santa Catarina, Brasil. gneckel@hotmail.com
authors.forename: Gecioni
authors.initials: G
authors.lastname: Loch-Neckel
authors.forename: Janice
authors.initials: J
authors.lastname: Koepp
mesh_terms: D001692:Biological Transport / Q000502:physiology*; D001812:Blood-Brain Barrier / Q000502:physiology*; D001927:Brain Diseases / Q000188:drug therapy / Q000503:physiopathology; D002490:Central Nervous System / Q000033:anatomy & histology / Q000378:metabolism*; D016503:Drug Delivery Systems; D008565:Membrane Proteins / Q000378:metabolism; D004364:Pharmaceutical Preparations / Q000008:administration & dosage / Q000378:metabolism*
chemical_list: D008565:Membrane Proteins; D004364:Pharmaceutical Preparations