Nanoparticle-mediated delivery of Neurotoxin-II to the brain with intranasal administration: an effective strategy to improve antinociceptive activity of Neurotoxin

Background: Neurotoxin-II (NT-II), an analgesic peptide which was separated from the venom of Naja naja atra, is endowed an exceptional specificity of action that block transmission of the nerve impulse by binding to the acetylcholine receptor in the membrane. However, it has limited permeability across the blood-brain barrier (BBB) after intravenously (i.v.) injection. Methods: In this study, we explored the potential application of nanoparticles overcoated with polysorbate 80 (P-80-NP) as drug carrier system for the nasal delivery of NT and the antinociceptive properties of NT-loaded P-80-NP (NT-P-NP) were also evaluated. Results: The brain delivery of NT-II could be enhanced with nanoparticles coated with polysorbate-80 through intranasally (i.n.) administration. Compared with NT-II solution, NT-P-NP exhibited sustained release in vitro and higher concentrations of NT-II in the brain. The antinociceptive animal testing also revealed that intranasal delivery of NT-loaded nanoparticle coated with polysorbate-80 were able to promote better biodistribution of the drug into the brain. Conclusion: The nanoparticles overcoated with polysorbate-80 were capable of transporting the loaded drug across the BBB after intranasal administration.