Eluizione in vitro della gentamicina dal cemento acrilico in funzione della concentrazione di antibiotico nella mescola

This study was performed to assess in vitro gentamycin diffusion from beads of acrylic bone cement with different antibiotic concentration. In three 10 g packages of Palacos® cement, 125, 250, 500 mg of gentamycin base were respectively added before polymerization. The cement was handily rolled and molded into beads (six for each set) which were leached serially in ten- milliliter aliquots of phosphate-buffered salin solution at pH 7.4 and incubated overnight at 37 °C, together with a control set of 6 beads of pure cement. Each bead was transferred into a new ten-milliliter aliquot every twenty-four hours for 40 days. The concentrations of antibiotic in the solution were measured by the Agar diffusion test. The release patterns of gentamycin were similar in the three mixtures with an early and rapid decrease of gentamycin in the elution fluid. However, antibiotic concentrations in the elution fluid remained constantly higher for those beads containing more gentamycin. More than 90% of gentamycin contained in the beads, regardless of its concentration, was not retrieved in the elution fluid. On the bases of these experimental observations, possible clinical- therapeutic relevances are discussed.