Sustained release of antibiotics from bone spacer

Abstract

Bone spacer is a device developed to temporarily insert into the body to treat infected tissue caused by bone replacement. Burst release and short-time release of antibiotics from bone spacer not only limits their ability to clear infection but also causes tissue inflammation. Therefore, here we have fabricated bone spacers containing antibiotic-loaded particles, studied their antibiotic release character, and measured the compressive strength of PMMA cements. Four biocompatible particles were investigated. Vancomycin and erythromycin were used as hydrophilic and hydrophobic model drugs, respectively. Rice granules and calcium citrate particles were loaded with vancomycin and gave the percent loading of 84.9 ± 0.3% and 4.9 ± 3.2%, respectively. Ethyl cellulose and poly(lactic-co-glycolic acid) particles were loaded with erythromycin and gave the percent drug loading of 52.0 ± 5.0% and 6.0 ± 0.9%, respectively. Then the drug-loaded particles were impregnated into poly(methyl methacrylate) bone spacers. Antibiotics released from the obtained bone spacers into PBS buffer pH 7.4 was monitored at 37 ℃. Calcium citrate particles showed improvement in sustaining the release of vancomycin from bone spacer as comparing to rice granules and unloaded drug. In contrast, embedding erythromycin directly into the PMMA gave a better-sustained release of the drug, as compared to the uses of erythromycin-loaded particles. Adding encapsulated drug (vancomycin-loaded rice granules is excluded) into PMMA cement is weaken the compressive strength of PMMA composites. After drug release test, Both PMMA cement loaded with vancomycin-loaded rice granules and PMMA cement loaded with raw erythromycin showed a significant decrease of compressive strength.