New method for antibiotic release from bone cement (polymethylmethacrylate): Redefining boundaries

Abstract Introduction The increasing antimicrobial resistance is promoting the addition of antibiotics with high antistaphylococcal activity to polymethylmethacrylate (PMMA), for use in cement spacers in periprosthetic joint infection. Linezolid and levofloxacin have already been used in in vitro studies, however, rifampicin has been shown to have a deleterious effect on the mechanical properties of PMMA, because it inhibits PMMA polymerisation. The objective of our study was to isolate the rifampicin during the polymerisation process using microencapsulation techniques, in order to obtain a PMMA suitable for manufacturing bone cement spacers. Material and method Microcapsules of rifampicin were synthesised with alginate and PHBV, using Rifaldin ® . The concentration levels of rifampicin were studied by UV–vis spectrophotometry. Compression, hardness and setting time tests were performed with CMW ® 1 cement samples alone, with non-encapsulated rifampicin and with alginate or PHBV microcapsules. Results The production yield, efficiency and microencapsulation yield were greater with alginate ( p  = 0.0001). The cement with microcapsules demonstrated greater resistance to compression than the cement with rifampicin (91.26 ± 5.13, 91.35 ± 6.29 and 74.04 ± 3.57 MPa in alginate, PHBV and rifampicin, respectively) ( p  = 0.0001). The setting time reduced, and the hardness curve of the cement with alginate microcapsules was similar to that of the control. Discussion and conclusions Microencapsulation with alginate is an appropriate technique for introducing rifampicin into PMMA, preserving compression properties and setting time. This could allow intraoperative manufacturing of bone cement spacers that release rifampicin for the treatment of periprosthetic joint infection.