title: The influence of vacuum mixing on methylmethacrylate liberation from acrylic cement powder.
abstract: Polymethylmethacrylate (PMMA) bone cement is a biomaterial used to anchor prostheses during joint replacement surgery. Residual methylmethacrylate monomer (MMA) may be related with the cytotoxic effect of PMMA. The aim of the present paper was to investigate the effect of two different cement mixing methods: hand stirring at atmospheric pressure and under partial vacuum (0.330 and 0.154 bar) on residual monomer liberation in phosphate buffer saline solution from acrylic cement powder. Residual MMA content was determined by high-performance liquid chromatography. Mathematical models were applied to experimental dissolution data revealing that monomer release was significantly reduced in bone cement powder obtained at 0.154 bar vacuum pressure compared to the other mixing conditions. The kinetic models applied are consistent with a simple diffusion mechanism of the monomer from the polymer matrix.
authors.affiliation: Faculdade de Farmácia, Universidade de Lisboa, Av. das Forcas Armadas, 1600-083, Lisbon, Portugal. asimao@ff.ul.pt
authors.forename: A
authors.initials: A
authors.lastname: Bettencourt
authors.forename: A
authors.initials: A
authors.lastname: Calado
authors.forename: J
authors.initials: J
authors.lastname: Amaral
authors.forename: F M
authors.initials: FM
authors.lastname: Vale
authors.forename: J M
authors.initials: JM
authors.lastname: Rico
authors.forename: J
authors.initials: J
authors.lastname: Monteiro
authors.forename: M
authors.initials: M
authors.lastname: Castro
mesh_terms: D000179:Acrylates / Q000737:chemistry*; D000465:Algorithms; D001274:Atmospheric Pressure; D001672:Biocompatible Materials; D001843:Bone Cements / Q000737:chemistry*; D020366:Methylmethacrylate / Q000737:chemistry*; D008962:Models, Theoretical; D011208:Powders
chemical_list: D000179:Acrylates; D001672:Biocompatible Materials; D001843:Bone Cements; D011208:Powders; D020366:Methylmethacrylate