| Objective The aim of this study was to investigate the physicochemical property of chitosan neurotoxin nanoparticles(CS-NT-NP)taking advantage of Nanoparticles as Carrier material,and employing Ion cross-linking method.The models of pains made by physical and chemical factors were used to evaluate the pharmacodynamic indexes,which were to determine the optimal drug delivery and drug concentration.The tissue distribution study was used to evaluate its brain targeting performance after intransal administration.Studying CS-NT-NP’s effect of intranasal administration on the permeability of blood brain barrier and the serum levels of S100β was aimed to provide reference for other preparation study of brain targeting.Methods ①CS-NT-NP was prepared by ion crosslinking method with CS and TPP as a carrier material.The morphology of CS-NT-NP was observed by employing transmission electron microscope,and Laser particle size tester/Zeta potentiometer was used to estimate the mean particle size and Zeta potential.According to ultracentrifugation,the entrapment efficiency and drug loading was investigated;②The hot plate test and the writhing test were used to evaluate the analgesia effects of different routes of administration and dosage of different agents;③Fluorescence labeling was used to detect the distribution of chitosan neurotoxin nanoparticles after intranasal administration;④A formamide extraction-ultraviolet spectrophotometry method was employed to determine the concentrations of evans blue in brain by different route of administration and preparations.Qualitative analysis of fluorescence intensity and distribution of EB in brain tissue availed oneself of fluorescence microscopy.The serum S100β protein concentrations were determined by ELISA.Results ①The morphology of CS-NT-NP was spherical,and the mean partical size,Zeta potential,entrapmen efficiency and drug loding of NT were(98.65±2.89)nm,(25.67±1.94)mV,(65.71±0.07)%,(0.206±0.02)%,respectively,②The result of writhing test showed that NT preparations could reduce the writhing times in mice in 15min.There was significant difference between the intraperitoneal injection group,the intramuscular injection group and the saline group with the corresponding administration mode(P<0.05),and the inhibitory rates were 21.15%and 41.67%,respectively.The nasal administration group compared with the Ns group has the significant difference(P<0.01),the inhibition rate was 60.96%.The inhibitory rates of high,medium and low dose groups were 73.48%,57%and 49%respectively,while the mice in the high dose group showed slight poisoning at 20min.The result of hot plate test showed that the CS-NT-NP group began to take effect at 30min(P>0.05),and with a long duration of efficacy,the pain threshold of the mice increased obviously and peaked at 150min.Compared with the Ns group,30 and 60 min showed significant difference(P<0.05),and 90-150min showed a very significant difference(P<0.01).Compared with the NT in.group,90-150min showed a highly significant difference(P<0.01);③The results of tissue distribution experiment showed the CS-NT-NP and NT group after nasal administration could distribute quickly in plasma and different issues.After administration of 120min,the content of CS-NT-NP in.plasma,brain and liver was all significantly higher than that in group NT(P<0.05,P<0.01,P<0.05),while the content in kidney was significantly lower than that in group NT(P<0.05),and there was no significant difference between the other groups;④The results of BBB permeability showed that the group of CS-NT-NP in.and CS-NT-NP im’s peal time of the concentration of EB were higher than CS-NT-NP ip.,and nasal administration group(46.91μg/g)was significantly higher than intramuscular injection group(38.45μg/g)and intraperitoneal injection group(36.51μg/g)(P<0.05).Compared with NT in.,the concentration of EB of CS-NT-NP in.group in brain increased obviously,and showed significant difference at 90-120min(P<0.05,P<0.01);After the administration of fluorescence microscope,the number of spots in CS-NT-NP in.groups increased obviously,and the contents of S100β protein in serum of rats were also significantly increased.The rat brain slices observed under fluorescent microscope was showed the number of spots in CS-NT-NP in.groups and the contents of S100β protein in serum of mice were both increased significantly.Conclusion In this study,the chitosan neurotoxin nanoparticles intranasal delivery system is successfully constructed by the preparation,physical and chemical properties,pharmacodynamics and tissue distribution of Chitosan neurotoxin nanoparticles(CS-NT-NP).To investigate the effect of administration on the permeability of BBB,and study the possible mechanism of its invasion into the brain,which prove that chitosan neurotoxin nanoparticles can open the blood-brain barrier temporarily and reversibly to improve the delivery of drugs in brain. |
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