[Transport of the hexapeptide dalargin across the hemato-encephalic barrier into the brain using polymer nanoparticles].

The drug targeting to the brain by polysorbate 80-coated nanoparticles was studied. The leu-enkephalin analog dalargin was used as a model drug for investigating the drug penetration through the blood-brain barrier. The nociceptive threshold was measured by the tail flick test. The intravenous injection of dalargin bound by sorption to poly(butylcyanoacrylate) nanoparticles subsequently coated with polysorbate 80 induced the analgesic effect in 5.0 and 7.5 mg/kg doses. The pretreatment with naloxone prevented this effect No other controls exhibited the analgesic activity, including the dalargin solution (10 mg/kg, i.v.), dalargin bound to nanoparticles not coated with polysorbate 80; and a simple mixture of dalargin, nanoparticles, and polysorbate 80 mixed directly before the intravenous injection. The luminescent and electron microscopy demonstrated the presence of separate nanoparticles in the capillary endothelium and cerebral neurons, as well as luminescent-labeled polymer in Purkinje's cells of the cerebellum.