Release of Gentamicin from Acrylic Bone Cement

Abstract

The pharmacokinetics of gentamicin were studied after total hip joint arthroplasties performed with "Palacos R plus gentamicin' in 10 patients. Urine was collected at 12-hour intervals for 15 days after operation, and drainage fluids for 48, 72 or 108 hours. Blood samples were taken 3 and/or 5 hours after prosthesis implantation. High concentrations of gentamicin were found in drainage fluids. Excretion curves in drainage fluids or urine were fitted by a computer-aided design program (SIAM) and the mean curves established. Elimination of gentamicin was biphasic in both cases. The rapid phases had a half-life of 2.97 hours in drainage fluids and 7.16 hours in urine. Half-lives of the slow phases were 13.5 and 47.12 hours, respectively. The mean percentage of total gentamicin released by the two routes was 5.78% of the quantity implanted. The calculated peak blood concentration was 0.12 mg/L. It is concluded that gentamicin concentrations locally reach levels higher than minimum inhibitory concentrations of most of the likely pathogens in patients undergoing total hip joint arthroplasties with "Palacos R plus gentamicin' bone cement. However, as blood concentrations appear to be low, patients may not be protected against systemic infections.

Sufficient Release of Antibiotic by a Spacer 6 Weeks after Implantation in Two-stage Revision of Infected Hip Prostheses

“…Our data showing a local tissue concentration of antibiotics in excess of the MIC, even after 6 weeks of implantation, are consistent with data from the few studies analyzing antibiotic levels around the spacer in vitro or aspirates after several weeks [4,21,32]. Moreover the low rate of recurrence of infection with a two-stage approach supports the conclusion that the spacer releases sufficient, high amounts of antibiotics after that interval to treat infection and is not just fulfilling a physical, jointmaintaining function [9,10,25].…”

“…The question, whether a sufficient concentration of antibiotic in vivo is ensured for the entire spacer period, could not be answered satisfactorily in previous studies with spacers and the usual antibiotics. Previous in vivo studies of the release of antibiotics from bone cement have showed that only a minor portion (5%-18%) of gentamicin incorporated in bone cement is eluted [4,33].…”

“…Several studies of local antibiotic concentrations in vivo have reported high concentrations in wound drainage fluid during the first few days after spacer implantation [4,15,36]. However, little data address the release of antibiotics from spacers in vivo after several weeks.…”

The effect of mixing on gentamicin release from polymethylmethacrylate bone cements

“…This is unlike the situation in Europe, where a variety of different antibioticloaded bone cements are commercially available. In vitro and in vivo studies have shown that only small amounts of the antibiotics incorporated in bone cement are actually released (Schurman et al 1978, Hoff et al 1981, Törholm et al 1983, Bunetel et al 1989, Chohfi et al 1998, because the release is largely a surface phenomenon. Antibiotics elute rapidly from the outer 50-100 µm of bone cement.…”

High local concentrations without systemic adverse effects after impaction of netilmicin-impregnated bone

“…However, the preliminary results of several pilot studies formed the basis for the estimation of the study sample. (Wahlig and Dingeldein 1980, Wahlig et al 1984, Salvati et al 1986, Bunetel et al 1989, Lindberg et al 1991) and 9-43 mg/ L of tobramycin (Soto-Hall et al 1983, Brien et al 1993, Masri et al 1998, Della Valle et al 2001). To our knowledge, the netilmicin peak values in drainage fluid recorded in our study have been the highest recorded to date.…”