Injectable acrylic bone cements for vertebroplasty based on a radiopaque hydroxyapatite. Bioactivity and biocompatibility

摘要

Radiopaque bone cements have been formulated to provide injectable pastes withudimproved bioactivity to be applied in vertebroplasty and kyphoplasty techniques. Theudbioactive compound was strontium containing hydroxyapatite salt, which was introduced asudobtained (SrHA) or after treatment with MMA monomer (SrHA-t). The in vitro bioactivity ofudthe cements was tested in cement films or in cement pastes introduced directly in a simulatedudbody fluid (SBF) solution at 378C to mimic the in vivo conditions. Precipitation of an apatitelikeudlayer was observed for the 20 wt %-SrHA-t containing cement in the first experiments,udand in all formulations in the second ones. The deposited particles were characterized by FTIRudspectroscopy and by EDAX analysis. Radiopacity of cements after immersion in SBF wasudconfirmed. The biocompatibility exhibited by the SrHA containing cements was, in some cases,udsuperior to that shown by a formulation with 10 wt % of BaSO4. The new formulationsudprepared with the treated filler exhibited the lowest cytotoxicity and enhanced cellularudproliferation. The in vivo biocompatibility tested by an intramuscular model in rats indicatedudthe formation of a membrane formed by collagen fibers containing fibroblasts withudno inflammatory cells, such as macrophages, giant cells or lymphocytes in all formulations