The Effect Of Low Molecular Weight Heparin Gel In A Mouse Model Of Pruritus And Pharmacokinetic Analysis After Transdermal Administration

In this dissertation,we choose low molecular weight heparin(LMWH)as the research object,through L9(34)orthogonal design to optimize the prescription of LMWH gel,to observe the antipruritic effects in a mouse model of pruritus induced by the proteinase-activated receptor-2 agonist,SLIGRL-NH2,after LMWH gel being percutaneous administrated,and to explore the pharmacokinetics characteristics of LMWH gel in the local skin tissue and plasma of rats after being percutaneous administrated.In this dissertation,the main research contents and research results have the following several aspects:1.The optimization of low molecular weight heparin gel prescriptionL9(34)orthogonal design was used in transdermal experiment in vitro with the accumulative penetration amount in 12 h as the evaluation index to optimize the prescription of LMWH gel.The optimal prescription were determined by the experimental data,as 3% low molecular heparin,5% azone,and 1.5% carbomer.The comparison results of three factors on the accumulative penetration amount showed that low molecular weight heparin had the greatest effect on the gel accumulative penetration amount,followed by azone,and carbomer.Through the in vitro investigation of the optimal prescription gel in transdermal experiment,the results showed that average of the cumulative permeation amount in 12 h was(142.23±4.60)?g,and the optimal prescription had the highest cumulative permeation quantity in 12 h,compared with the initial 9 prescriptions.2.To study the effect of microdialysis on the in vivo and vitro recovery of low molecular weight heparinThe effect of perfusion flow rate on the in vitro recovery for dermal probe was detected by increment and decrement method,and the effect of concentrations of low molecular weight heparin on the in vitro recovery for dermal probe was determined by decrement method.The effect of perfusion flow rate and concentrations of low molecular weight heparin on the in vivo recovery for dermal probe was determined by decrement method.The in vivo and vitro recovery for dermal probe detected by increment was accordance with the decrement method;The LMWH recovery increased when the flow rate decreased,and LMWH recovery was independent of LMWH concentration in the external medium.The vivo recovery stability of linear probe was detected by decrement method,when perfusion flow rate of linear probe was 2 ?L/min,the in vivo recovery of LMWH was steady in 8 hours for linear probes,and the average recovery of linear probe was(60.42 ± 3.78)%.So we can conclude that the microdialysis technique can be employed to determine the pharmacokinetics of LMWH gel in rat dermis.3.To investigate the skin pharmacokinetic characteristics of LMWH gel after be percutaneous administrated in SD rats by microdialysis techniqueLinear probe was embedded in the abdominal subcutaneous after 24 h for abdominal hair removal of SD rats.The skin above dialysis membrane of linear probe was given 0.2 g LMWH gel(containing 600 Anti FXa IU LMWH),and taking a dialysate sample every 30 mins and continuous acquisition in 12 h.Based on the LMWH concentration-time profile in dermal of SD rats,the pharmaceutics parameters of LMWH gel in the skin of rats by was calculated noncompartment models.The result showed that the LMWH Tmax in dermis was 270 min,(4.40 ± 0.54)IU·m L-1 for Cmax,(137.04 ± 87.98)min for T1/2,(911.76 ± 330.69)IU·m L-1·min for AUC0-t,(322.67 ± 40.94)min for MRT0-t after LMWH gel was percutaneous administrated.4.The pharmaceutics parameters of LMWH gel in plasma of SD rats after be percutaneous administratedLMWH gel(600 Anti FXa IU)was percutaneous administrated on abdominal of SD rats after 24 h for abdominal hair removal.The blood samples was obtained by cutting-tail method at 1 h before administration and 1 h,2 h,4 h,5 h,6 h,8 h,9 h,10 h,12 h after administration.Plasma was obtained after blood being treatment,then LMWH concentration in plasma of SD rats was detected with Coatest Heparin Kit.Based on the LMWH concentration-time profile in plasma of SD rats,the pharmaceutics parameters of LMWH gel in the plasma of rats was calculated by noncompartment models.The result showed that the LMWH Tmax in plasma was 540 min,(2.23 ± 0.40)IU·m L-1 for Cmax,(294.99 ± 183.74)min for T1/2,(110.59 ± 212.41)IU·m L-1·min for AUC0-t,(422.48 ± 52.96)min for MRT0-t after LMWH gel was percutaneous administrated.5.To verification the antipruritic effect of low molecular weight heparin in a mouse model of pruritusThirty-two BALB/c mice were randomly divided into four groups: control group,model group,compound dexamethasone acetate cream group and LMWH gel group,8 rats in each group.With blank gel,blank gel,compound dexamethasone acetate cream and LMWH gel,0.1 g of each were applied directly to the skin removed hair in the nape,respectively,twice a day for 3 days.Two hours after the last dosing,local intradermal injection of saline solution was made in the nape of the control mice,and intradermal injection of PAR-2 agonist SLIGRL-NH2 was given in the nape of the remaining of the three groups of mice.The scratching behavior was observed within 30 min after intradermal injection.The results showed that the amount of scratching in the model group increased,compared with the control group(P<0.05).The amount of scratching in compound dexamethasone acetate cream group decreased,compared with the model group(P<0.05).The amount of scratching in low molecular heparin gel group decreased,compared with both the model and compound dexamethasone acetate cream groups(P<0.05).Therefore,3% LMWH gel can relieve the pruritus induced by SLIGRL-NH2,and its antipruritic effects is superior to compound dexamethasone acetate cream.