Intravascular Dilivery Of Tumor Hypoxia-targeting TH-302-PLGA Eluting Beads For Rabbit Model Bearing VX2 Liver Tumor Treatment:An Experimental Study

Objective:(1)To explore the preparation process of the new TH-302-PLGA sustained-release microsphere and to determine its release degree in vitro.(2)To evaluate the sustained release ability and safety of the new-type TH-302-PLGA sustained-release microspheres in the normal rabbit liver tissues after the arterial importing.(3)To evaluate the anti-tumor effect of the new TH-302-PLGA sustained-release microsphere with traditional TACE as the control.Materials and Methods:(1)To investigate the key factors influencing the formulation process of the new embolization microspheres:the proportion of LA and GA;the size of PLGA molecular weight;Seal end situation of PLGA;Impeller speed;the speed of the injection of oil phase into the water phase;PH of water phase;The osmotic pressure difference between water phase and oil phase;Whether or not a mixture of methanol.Methods for determination of in vitro release degree:Weigh accurately 20mg microspheres in a 250ml conical flask,adding 100ml release medium,respectively,in 1,2,3,4,6,8,10,12,24,30,36,48h get 5ml sampling,the supernatant was 2ml.The cumulative release of the microspheres was measured by high performance liquid chromatography.(2)75 New Zealand rabbits were randomly divided into 5 groups,respectively by hepatic artery injection of different drugs,group 1(75-100microsphere);group2(100-200microsphere);group3(200-300microsphere);the control group A(TH-302-lipiodol);the control group B(TH-302-saline group).The observation indexes include the function of liver and kidney,adverse reaction and concentration of blood,and draw a drug-time curve.(3)A total of 40 experimental rabbits were selected to establish rabbit VX-2 liver cancer models.They were divided into 5 groups,8 rabbits in each group,group A:microsphere group;group B:adriamycin-lipiodol group;group C:TH-302-lipiodol group;D group:PVA granule group;E group:TH-302-saline group.The interventional therapy was performed respectively.Before interventional therapy,the liver enhanced CT examination was performed at 3,7,and 14d after intervention.The tumor volume was evaluated and the mRECIST standard was used to evaluate the short-term effect.Results:(1)According to the investigation above,different particle size microspheres were prepared by changing the velocity of oil phase into the water phase.The molecular weight of the carrier is 9800,and the LA:GA is PLGA of 75:25.(2)all the experimental rabbits were successfully operated and survived for 1 weeks.No serious complications occurred after operation,and the incidence of limb edema was high(25/50,50%).Most of them were improved without special treatment.There was no significant difference in the values of ALT,AST,CREA and UREA at different time after operation(P>0.05).Cmax and AUC of the concentration time curve respectively is 2.60?2.78?2.45?1.24?1.10?g/ml,5.01?5.00?4.87?3.29?2.05?g/mL-min;between the 2 and the 3 groups had no significant difference(P>0.05),1/2/3 group and A/B group was statistically significant difference(P<0.05).(3)MRECIST standard assessment results:A group and B group were partial remission(PR).The C group was evaluated as progress(PD),D group evaluation as progress(PD),E group evaluation as progress(PD).The volume values of group A at different time were 2.68,1.85,1.47 and 1.51cm3;group B:2.74,2.30,2.05,2.24cm3;C group:2.50,2.15,2.19,4.86cm3;D group:2.65,2,2 and 5.02cm3;E group:2,2,2.19,4.86cm3.Conclusion:(1)Polylactic acid glycolic acid copolymer(PLGA)is a reliable and stable TH-302 carrier.The preparation of new TH-302-PLGA drug loaded microspheres is technically feasible.In the future,some technologies in microsphere preparation may be applied to industrial production.(2)In vivo release properties of novel TH-302-PLGA microspheres has good stability,and the safety and tolerability of the local medication is good,no serious adverse events were observed and have no extra hepatic and renal toxicity;As the physicochemical properties of PLGA and TH-302 and their own biological activity,they may play a synergistic effect in the treatment of in the process of TACE.(3)In the rabbit VX2 liver cancer model,the efficacy of the new TH-302-PLGA drug loaded microspheres showed no advantage over the traditional TACE,but the effect is also worthy of further study.