Biomechanics Properties And Histocompatibilty Of Risedronate Compounded Calciumphos Phate Cement

ObjectiveTo construct Risedronate-calcium phosphate cement skeletal drug delivery system.Use calcium phosphate bone cement as local delivery carrier and release the risedronatesodium for anti-osteoporosis treatment at the same time of injection calcium phosphatebone cement to strengthening the vertebral. Give experimental basis to improvepercutaneous vertebroplasty and percutaneous kyphoplasty treatment effect bydrug-loaded injectable bone cement by minimally invasive surgery.Methods1. Calcium phosphate bone cement solid powder and risedronate sodium powderwere mixed according to mass fraction at0.1%,0.5%, and1%respectively. Then a tapered VEKA test pin was used to test polymerization time of drug-loaded calcium phosphatecement. With risedronate sodium in different concentrations of the drug-loaded calciumphosphate cement were prepared for models, using the Zwick Z050electronic tensiletesting machine, SHIMADZU UH-F100OKNC hydraulic universal testing machine andthe MTS810Material Test System fatigue test machine to test event compressiveproperties, bending properties, and fatigue performance.2. Putting the different concentrations of the drug-loaded calcium phosphate cement(mass fraction at0.1%,0.5%, and1%) in the30ml PBS, dipping in biochemical incubatorat37℃, determination of extract concentration at1d,3d,7d,14d,21d,28d,35d,42d,49d,56d,84d,112d140d, and168d.3. Separation, culture and identification of osteoblasts of newborn fetal rats calvarialbone that were born within48hours. The cells were cultured in DMEM culture liquidextract liquid, DMEM extraction,1:3DMEM medium containing5%PBS extract, DMEMmedium containing10%PBS extract, DMEM medium containing15%PBS the leachingliquid medium DMEM for1days,2days, and3days, and relative survival rate of cellswas measured with MTT method each day.4. The bone cement specimens was implanted into rabbit femur and respectively takeout after4,8,12and24weeks. The degradation performance was detected by qualityweighing and the histocompatibilty was detected by histology.Results1. With the increase of risedronate sodium powder concentration, initial setting timeof calcium phosphate cement and the final setting time were extended to varying degreesand compression strength gradually decreased. The1%mass fraction of the risedronatesodium drug-loaded calcium phosphate cement compressive strength test value wasobvious near the calcium phosphate cement raw materials compressive strength limitvalue (35Mpa). After solidification, the flexural strength and fatigue resistance ofdrug-loaded calcium phosphate cement had no significant difference comparing with thecontrol group (p>0.05). The bending modulus decreased with increasing load ofrisedronate sodium powder concentration. Compared with the control group, there wassignificant difference at bending modulus in the1%mass fraction of risedronate sodiumdrug-loaded calcium phosphate cement (p=0.004).2. The release rate increased with leaching time decreasing, which was fast at beginning and then slow down. At the same time, the release rate increased with the increase ofrisedronate in bone cement. Within1week, the total release percentage of all groupswere similar, at about11%. After3-7days,the transition period got into a slow releaseperiod, and the total release percentage at168days was less than20%. In the quick releaseperiod, slope release percentage of all groups was consistent, but in the slow release period,there were differences in the total slope release percentage, namely group3> group2>group1.3. With the increase mass fraction of risedronate sodium in the calcium phosphatecement and extraction time, toxicity gradually increased on fetal rat primary culturedosteoblastic cells.4. Risedronate compounded calcium phosphate cement has a good histocompatibilty.To increase the mass fraction of the composite of risedronate sodium will accelerate itsdegradation.Conclusions1. In order to ensure the mechanical strength of calcium phosphate cement for theneeds of clinical work, the mass fraction of the risedronate sodium content should notexceed1%.2. Risedronate could be slowly released from bone cement. In quick release period,the transition period and slow release period, the release rate increased with the increase ofrisedronate.3. When local application of risedronate sodium drug-loaded calcium phosphatecement,the fact that the risedronate inhibited osteoclast and osteoblast should be fullyconsidered.4. Risedronate compounded calcium phosphate cement has a good histocompatibilty.The drug composite reasonable proportion in favor of accelerating the degradation of CPC.