Influence of the type of surfactant on the analgesic effects induced by the peptide dalargin after its delivery across the blood-brain barrier using surfactant-coated nanoparticles

The ability of 12 different surfactants, coated onto the surface of nanoparticles, to facilitate the delivery of a nanoparticle-bound model drug, dalargin, was investigated. The leu-enkephalin analogue hexapeptide dalargin was bound to polybutylcyanoacrylate nanoparticles by sorption for 3 h. Different surfactants were then coated over these nanoparticles and were injected intravenously into mice. Nociceptive analgesia was then measured by the tail-flick text 15, 30, 45 and 90 min after injection. Only nanoparticles that had been coated with polysorbate 20, 40, 60 and 80 yielded a significant effect. The highest effect was observed with polysorbate 80. Maximum effects were found after 15 min, at a dalargin dosage of 10 mg/kg, and after 45 min, with 7.5 mg/kg. (C) 1997 Elsevier Science B.V.