Basic Research Of Chemotherapeutic Drugs-loaded Polymethyl Methacrylate Bone Cement As Drug Delivery Carrier

Objective:To screen out thermostable antineoplastic that could be loaded in polymethylmethacrylate (PMMA) bone cement;To investigate the mechanical property and microstructure of PMMA which loaded with either single or combined of methotrexate (MTX)and epirubicin (EPI) by various mass ratios and seek out the high dose of MTX and EPI that could be loaded in PMMA bone cement; To investigate the drug release properties and potencies of MTX and EPI loaded PMMA bone cement in vitro;To investigate the mechanical property and microstructure of drug loaded PMMA that after drug released experiment in vitro;To provide the theoretical basis to make MTX and EPI loaded PMMA bone cement.Method:1、Prepare the various concentrations of MTX solution (10、20、40、 80、160μg/ml) and EPI solution (1.25、2.5、5、10、20μg/ml) and heat treatment experiment group at 75℃ for 10 minutes while the control group at room temperature. Then use the CCK-8 kit to detect the pharmacological activity of MTX and EPI which add in MG63 and U2OS cell line.2、MTX was mixed with PMMA by mass ratio of 1%,2%,4% respectively, while EPI was mixed by 0.1%,0.2%,0.4% respectively. Both of MTX and EPI were mixed with PMMA by mass ratio of 1%+0.1%、2%+0.2%、4%+0.4%, of which mechanical property (bending strength, compressive strength, bending modulus) and microstructure were detected respectively.3、MTX was mixed with PMMAby mass ratio 2% while EPI was mixed by 0.1% to be made drug loaded PMMA standard component respectively. Put every PMMA standard component into every eppendorf tube which containing 10 ml 37℃ saline after weigh and record the mass. Replace the saline every 24 h and put the solution into -20℃ refrigerator at 1、2、3、5、7、10、15、20、30day.Then use high performance liquid chromatography (HPLC) to detect the solution.4、Use CCK-8 kit and 143b cell line to detect the potencies of MTX and EPI solution which deteted by HPLC.5、MTX was mixed with PMMA by mass ratio 2% while EPI was mixed by 0.1% to be made drug loaded PMMA standard component respectively. Put the PMMA standard components into a airtight container which containing 500 ml 37℃ saline and replace the saline every 24 h last 5 months. Then detect the mechanical property (bending strength, compressive strength, bending modulus) and microstructure of PMMA standard components.Results:1、Comparied with control group, it revealed that the potencies of MTX and EPI were not significantly reduced after thermal treatment through the ANOVA analysis (P>0.05).2、Mechanical property indexes of drug loaded bone cement,mixed with either single or combined of MTX and EPI by corresponding mass ratio, were higher than the international reference value. In regression analysis, mass ratio of combined MTX and EPI with PMMA had no significant effect on compressive strength or composite bending modulus(P>0.05). Mass ratio of EPI and PMMA significantly affect compressive strength (P<0.05, B=2315.305) while mass ratio of MTX and PMMA did not significantly affect compressive strength(P>0.05)by regression analysis. The irregular porosity on the surface of drug loaded PMMA bone cement was reduced and became shallower.3、MTX and EPI could released from the drug loaded PMMA bone cement and MTX solution concentration whit a very high peak value at the first day then sharp decline at the next two days and remaining at low level in the next days while EPI solution maintain at low level all the time relatively.4、Comparied with control group, it revealed that the potencies of MTX and EPI solution,which released from the drug loaded PMMA bone cement at the thirtieth day, had significant effect on cell survival rate through the t test analysis (P>0.05).5、MTX was mixed with PMMA by mass ratio 2% while EPI was mixed by 0.1% to be made drug loaded PMMA standard component respectively. Mechanical property indexes of drug loaded bone cement mixed by corresponding mass ratio were higher than the international reference value after the drug release experiment. Compared with the control group the drug particle loaded on the surface of PMMA decreased significantly after the drug release experiment.Conclusion:The potencies of MTX and EPI are not significantly decreased after exothermic process of PMMApolyreaction; Mechanical property indexes of drug loaded bone cement, mixed with either single or combined of MTX and EPI by corresponding mass ratio, were higher than the international reference value.MTX and EPI with antineoplastic function could released from the drug loaded PMMA bone cement in long-term steadily. PMMA bone cement could be used as a drug delivery.