Abstract
Elution of antibiotics from antibiotic-loaded polymethylmethacrylate (AL-PMMA) increases when soluble particulate filler is added to increase the permeability of the PMMA. Antibiotic powder is in itself soluble particulate filler. For greater volume fractions of filler, greater elution occurs. The volume of generic tobramycin powder is more than 3.5 times the volume of proprietary tobramycin powder for a 1.2 g dose leading to the question: Does generic tobramycin elute from AL-PMMA faster than proprietary tobramycin? We performed elution studies on AL-PMMA beads made with 1.2 g of either generic tobramycin or proprietary tobramycin per batch of PMMA. Generic tobramycin eluted more than two times faster than proprietary tobramycin. The release mechanism started as dissolution-driven zero-order release for the generic bead set but for the proprietary bead set the released mechanism started as anomalous diffusion. The release mechanism progressed to diffusion-driven first-order release in both. The increased volume of the generic tobramycin caused more tobramycin to be available for release. The increased elution of tobramycin associated with the greater volume of generic tobramycin powder could lead to clinically higher levels of tobramycin in wound fluid and local tissues; however, the higher volume of powder could potentially cause greater mechanical compromise of the PMMA.
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References
DeLuise M, Scott CP. Addition of hand-blended generic tobramycin in bone cement: effect on mechanical strength. Orthopedics. 2004;27:1289–1291.
Korsmeyer RW, Gurny R, Doelker E, Buri P, Peppas NA. Mechanisms of solute release from porous hydrophilic polymers. Int J Pharm. 1983;15:23–25.
Kuechle DK, Landon GC, Musher DM, Noble PC. Elution of vancomycin, daptomycin, and amikacin from acrylic bone cement. Clin Orthop Relat Res. 1991;264:302–308.
McLaren AC, McLaren SG, Hickmon MK. Sucrose, xylitol and erythritol as fillers to increase permeability of PMMA for depot delivery of antibiotics. Clin Orthop Relat Res. 2007;461:60–63.
McLaren AC, McLaren SG, Smeltzer MS. Xylitol and glycine fillers increase permeability of PMMA to enhance elution of daptomycin. Clin Orthop Relat Res. 2006;451:25–28.
McLaren AC, Nelson CL, McLaren SG, DeClerk GR. The effect of glycine filler on the elution rate of gentamicin from acrylic bone cement: a pilot study. Clin Orthop Relat Res. 2004;427:25–27.
McLaren AC, Nelson CL, McLaren SG, Wassell DL. Phenolphthalein used to assess permeability of antibiotic-laden polymethylmethacrylate: a pilot study. Clin Orthop Relat Res. 2005;439:48–51.
Neut D, van de Belt H, van Horn JR, van der Mei HC, Busscher HJ. Residual gentamicin-release from antibiotic-loaded polymethylmethacrylate beads after 5 years of implantation. Biomaterials. 2003;24:1829–1831.
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One or more of the authors (ACM) has received donation of Palacos® PMMA from Biomet Inc, Warsaw IN, and tobramycin sulfate (Nebcin® and generic) from Banner Health, Phoenix, AZ. One or more of the authors (ACM, BV) has received funding from DePuy Inc, Warsaw, IN.
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McLaren, R.L., McLaren, A.C. & Vernon, B.L. Generic Tobramycin Elutes From Bone Cement Faster Than Proprietary Tobramycin. Clin Orthop Relat Res 466, 1372–1376 (2008). https://doi.org/10.1007/s11999-008-0199-2
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DOI: https://doi.org/10.1007/s11999-008-0199-2