Study On Preparation And Pharmacokinetic Evaluation Of Solid Lipid Nanoparticles Of Carbamazepine And Its Effect On P-glyprotein Expression In Brain

Aims The aim of this paper was to prepare the solid lipid nanoparticles of carbamazepine(CBZ-SLN),to evaluate the effect of single dose CBZ-SLN on pharmacokinetic,and to investigate the effect of repeated administration on drug concentration in brain,and the expression of P-gp in brain of mice.Methods(1)The CBZ-SLN was prepared by high temperature emulsification-low temperature curing technique.The morphology of CBZ-SLN was observed under transmission electron microscope.Particle size and Zeta potential of CBZ-SLN were measured by dynamic light scattering using a computerized inspection system.The entrapment efficiency was determined by high performance liquid chromatography(HPLC).(2)2 5 0 ma l e Ku n m i n g mi c e w e r e r a n d o ml y d i vi d e d i n t o f i ve g r o u p s : C B Z-S LN,CBZ+Ver,CBZ-SLN +Ver,CBZ+SLN and CBZ.Mice were intraperitoneally injected with differentsolution.For mice,the blood and brain was collected,at 10,15,30,45,60,120,240,360,480,600 minites of the last administration.The concentration of CBZ in blood and brain was determined by HPLC,and the main pharmacokinetic parameters were calculated by DAS software.(3)80 male Kunming mice were randomly divided into groups: CBZ-SLN,CBZ+Ver,CBZ+SLN and CBZ.Mice in CBZ group were intraperitoneally injected with differentsolution;Mice were sacrificed by collecting brains from the mice after 120 minutes of last administration at 1days,7days,14 days,and 21 days,respectively.The HPLC method was applied for measuring the drug concentration inSampleof brain.(4)100 male Kunming mice were randomly divided into groups: CBZ-SLN,CBZ+Ver,CBZ-SLN +Ver,CBZ+SLN and CBZ.Mice in CBZ group were intraperitoneally injected with differentsolution;Mice were sacrificed by collecting brains from the mice after 120 minutes of last administration at 1days,7days,14 days,and 21 days,respectively.The protein expression level of P-gp in brain after administration for 1 day,7 days,14 days,and 21 days was evaluated by Western Blot.The mRNA expression level of P-gp in brain after administration at 1 day,7 days,14 days,and 21 days was evaluated by RT-qPCR.Results(1)It showed that the CBZ-SLN had round shapes and stability;the average particle size is(310.20 ± 10.04)nm;the Zeta potential is(-30.50 ± 0.98)mv;the encapsulation efficiency is(70.9 ± 3.0 %).(2)After single dose administration,copared with the CBZ gourp,the AUC of CBZ-SLN gourp and CBZ+Ver group were increased by 88% and 64%,respectively.The T1/2 values were increased significantly,whereas the CL values were significantly decreased.Compare with CBZ group and CBZ+SLN gourp,the brain drug concentrations were significantly increased both in CBZ-SLN group and CBZ+Ver goup.However,compare with CBZ goup,the plasma drug concentrations had no significant difference between CBZ+SLN group and CBZ group.Thus,CBZ-SLN can effectively increase the concentration of CBZ in the brain,which may be related to its reduction in P-gp to CBZ efflux.(3)After administration for 1days,7 days,14 days and 21 days,there was no significant difference between CBZ+SLN group and CBZ group in drug concentrationin brain.Compared with CBZ group,The brain drug concentrations of CBZ-SLN gourpwere increased by 55%,53%,110%,180%,after treatment for1 days,7 days,14 days,and 21days;Compared with CBZ group,braindrug concentration ofCBZ+Ver group was evidently increasedby 67%,47%,68%,125%,aftertreatment for1 days,7 days,14 days,and 21 days.(4)Compared with normal group,the expression of P-gp was increased in CBZ group,CBZ-SLN,CBZ+Verand CBZ+SLN group after administration for 14 days and 21 days.However,Compared with CBZ group,CBZ+SLN group and CBZ+Ver group,the expression of P-gp was significantly increased in CBZ-SLN group;The expression trend of P-gp mRNA is consistent with the trend of protein expression.Conclusions(1)The CBZ-SLN prepared by high temperature emulsification-low temperature curing technique showed good reliablility,accuracy and operability.the prepared solid lipid nanoparticles of CBZ-SLN show spherical nanoparticles with good encapsulation efficiency and stability.Furthermore,the materials used in SLN making had no influence on pharmacokinetic of CBZ.(2)After CBZ loaded in the SLN,on the one hand contributes to the increase of cell endocytosis,On the other hand it can offset part of the induction of P-gp by CBZ on brain,so that P-gp efflux of CBZ relatively reduced,increasing the amount of CBZ into the brain tissue.