TITLE:
Kinetics of Elution of Gentamicin from a Gentamicin-Loaded PMMA Bone Cement
AUTHORS:
Gladius Lewis, Li Li
KEYWORDS:
Poly (Methyl Methacrylate) Bone Cement, Gentamicin, Elution, Diffusion Coefficient, Kinetics Models
JOURNAL NAME:
World Journal of Engineering and Technology,
Vol.7 No.3,
August
15,
2019
ABSTRACT: Antibiotic-loaded poly (methyl methacrylate)
bone cement (ALBC) is widely used for anchoring joint replacements as a means
of reducing the potential for peri-prosthetic joint infection (primary cases)
and treating a patient who has an infected joint replacement (revision cases).
One shortcoming of the cement is the high maximum exothermic temperature experienced
upon polymerization (Tmax), a phenomenon that, it has been postulated,
may cause or be implicated in thermal necrosis of peri-prosthetic tissues.
There are many reports in the literature on methods of reducing Tmax,
with one such study involving the addition of a phase change material
(microencapsulated paraffin) (MEPAR) to the cement powder or adding a chain-stopping
chemical (1-dodecyl mercaptan) (DDM) to the liquid. In that report, the results of gentamicin elution tests were presented. In the present work,
those results were used to calculate various indices of gentamicin elution
kinetics, namely 1) diffusion coefficient (Dgent); and 2) values of
the coefficients in four equations that are widely used to model antibiotic
elution from ALBCs. We found 1) the difference in Dgent of either a
MEPAR- or DDM-containing formulation, on the one hand, and that of the control
cement, on the other, was not significant; and 2) a consistent trend in the
value of only one coefficient in one of the four model equations, with this
change suggesting insignificant difference in gentamicin elution mechanism
between an experimental cement formulation
and the control cement. The implications of these findings for guiding
selection of additives that simultaneously produce significant reduction of Tmax but minimal effect on gentamicin elution kinetics are discussed. This
guide is a novel contribution to the literature.