Preparation Of Co-modified Liposomes Of α-cobrotoxin And Its Pharmacokinetics Study After Intranasal Administration

Objective To prepare α-cobrotoxin(αCT)loaded liposomes co-modified with Pepl and Pep2[Pep2(Pep1)-αCT-LP],and investigate its physicochemical properties and release feature in vitro,and study its pharmacokinetics in rats after intranasal administration.Methods The αCT-LP was prepared by film dispersion method in this study,and orthogonal experiment was used to optimize the preparation procedure and formulation.DSPE-PEG2000-Pepl and DSPE-PEG2000-Pep2 were synthesized by Michael addition reaction and their structures were verified by proton nuclear magnetic resonance spectroscopy(1H-NMR)and infrared spectroscopy(FTIR).Then DSPE-PEG2000-Pep1 and DSPE-PEG2000-Pep2 as membrane material insert into the film of αCT-LP which prepared by the optimum process.The transmission electron microscope(TEM)and Zeta sizer instrument were utilized to investigate the morphology,particle size,polydispersity index and Zeta potential;The encapsulation efficiency of liposomes were determined by ultrafiltration centrifugal method and the drug release behavior in PBS buffer at pH 7.4 in vitro were studied by dialysis method.Brain microdialysis was used to determine αCT concentration in the brain of rats.Results αCT-LP was prepared by film dispersion method and optimal formulation was decided.EPC/ChoL was 3:1,FITC-αCT concentration was 14 μg·mL-1 and lipid concentration was 8.33 mg·mL-1.The spectra of 1H-NMR and FTIR were suggested that successfully synthesized DSPE-PEG2000-Pep1 and DSPE-PEG2000-Pep2.The prepared Pep2(Pepl)-αCT-LP was nearly spherical shapes with uniform size,the mean particle size was(115.8±1.86)nm and Zeta potential was(-13.77±0.75)mV.And the encapsulating efficiency was(32.75±1.12)%.The in vitro release profile of the αCT-LP and Pep2(Pepl)-αCT-LP in pH7.4 PBS buffer were both consistent with Weibull equation,that is lnln[1/(1-Q)]=0.54061nt-0.95 65,r=0.9674 and lnln[1/(1-Q)]=0.54981nt-1.0791,r=0.9913.Compared with αCT-LP,Pepl-αCT-LP,Pep2-αCT-LP,Pep2(Pep1)-αCT-LP after intranasal administration,Cmax in brain were(168.12±2.70)ng·mL-1,(215.17±4.52)ng·mL-1,(208.87±10.68)μg·mL-1,(244.72±3.15)μg·mL-1 respectively;Tmax in brain were(145.38±5.32)min,(119.11±4.51)min,(110.71±12.98)min,(88.01±4.19)min respectively;AUC0→t in brain were(61333.46±980.21)ng·min·mL-1,(73778.66±1244.27)ng-min-mL’1,(69316.06±1780.37)ng·min·mL-1,(74950.38±1568.25)ng·min·mL-1 respectively.It turned out that Pep2(Pep1)-αCT-LP after intranasal administration can improve the drug concentrations in the brain as were as its bioavailability,which make better play a role of dual-brain targeted drugs.Conclusion This article through to study the preparation,characterization,brain pharmacokinetics after intranasal administration of Pep2(Pep1)-αCT-LP,laid the foundation for the development of dual-brain-targeting drugs,at the same time as reference for the development of large molecules such as proteins and peptides.