Surface roughness, porosity and wettability of gentamicin-loaded bone cements and their antibiotic release

In this study, the release of gentamicin as a function of time was measured for six different gentamicin-loaded bone cements and related with the surf ace roughness, porosity and wettability of the cements. Initial release rat es varied little between the six bone cements (CMW1, CMW3, CMW Endurance, C MW 2000, Palaces, and Palamed) and ranged from 8.6 to 14.1 mu g/cm(2)/h. Th e total amounts of gentamicin released after 1 week varied between 4.0 and 5.3% of the total amount of antibiotic incorporated for the CMW cements and was 8.4% for Palaces. Palamed released after 1 week significantly more of the gentamicin incorporated (17.0%). The wettability of all cements was sim ilar (water contact angles between 70 and 80 degrees), but the surface roug hness and the porosity of the cements varied markedly. Initial release rate s increased with surface roughness, although the correlation coefficient wa s low (0.64), while total amounts released increased linearly (correlation coefficient 0.97) with the bulk porosity of the cements. Consequently, it c an be concluded that the release kinetics of gentamicin from bone cements i s controlled by a combination of surface roughness and porosity. (C) 2000 E lsevier Science Ltd. All rights reserved.