Characterization of alendronate sodium-loaded UHMWPE for anti-osteolysis in orthopedic applications

Ultra-high molecule weight polyethylene (UHMWPE) loaded with alendronate sodium (ALN), a potential drug to prevent debris-induced osteolysis, was developed in our previous study. This study aims to investigate the wear performance of UHMWPE-ALNs. In this study, wear test, mechanical test, differential scanning calorimetry (DSC) and contact angle test were applied to characterize the wear performance, mechanical behavior and physical properties of UHMWPE-ALNs. The effect of ALN on the wear performance of UHMWPE-ALNs was investigated by scanning electron microscope (SEM), back scattering electrons (BSE) and energy dispersive X-ray spectrum (EDX). The results of wear test showed that the friction coefficient and volumetric loss of UHMVVPE-ALN 0.5 wt.% were comparable with those of UHMWPE. The result of SEM-BSE-EDX revealed that the wear debris detached easily from the ALN-agglomerated regions, which was mainly responsible for the decrease of wear resistance of UHMWPE-ALN 1.0 wt.%. The loaded ALN resulted in the increase of hydrophilicity of UHMWPEALNs. The decrease of toughness and crystallinity of UHMWPE-ALN 1.0 wt.% attributed to the non-uniform distribution of ALN. The UHMWPE-ALN 0.5 wt.%, in which no ALN agglomeration was observed, possessed approving mechanical properties and wear performance, might have potential clinical application to prevent the debrisinduced osteolysis in prosthetic joints. (C) 2011 Elsevier B.V. All rights reserved.