Neurotoxin-I nanoparticles were prepared by emulsion polymeriz- ation method with polybutylcyanoacrylate(PBCA) as nanoparticle material.The shape,particlesize,ζ-potential and encapsulation efficiency of neurotoxin-I nano- particles were investigated.The brain delivery of neurotoxin-I nanoparticles coaded with tween-80 were evaluated using microdialysis sampling technique. Uncoaded nanoparticles were also evaluated in the same method.The results showed that compared with the pharmacokinetic parameters of unc...