Site-specific drug delivery to CNS: old and new.

Delivery of drugs to specific sites in the CNS represents an essential therapeutic challenge. Extradural administration of opiates successfully delivers drugs to the CNS. The levodopa-carbidopa combination achieved some degree of site-specific delivery by pharmacological methods. Antibiotics have been administered through cannula directly into ventricles. Invasive methods offer the greatest degree of site-specificity.