title: Infrared, Raman and NMR investigations of risedronate adsorption on nanocrystalline apatites.
abstract: The aim of the current work was to study the physico-chemical interactions of a bisphosphonate molecule, risedronate, with a well-characterised synthetic nanocrystalline apatite (NCA) as a model bone mineral. We adopted a global approach, using complementary physico-chemical techniques such as FTIR, RAMAN and NMR spectroscopies in order to learn more about the interaction process of risedronate with the apatitic surface. The results obtained suggest that risedronate adsorption corresponds to an ion substitution reaction with phosphate ions occurring at the crystal surface. This mechanism explains the greater amount adsorbed (N) for NCA, compared to well crystallised stoichiometric hydroxyapatite, attributable to the well-developed hydrated layer at the surface of the nanocrystals. However, most calcium ions remain attached to the solid phase and the formation of insoluble risedronate calcium salts must also be considered as a competitive reaction to the adsorption. Thus a calcium risedronate salt was synthesised and fully characterised for comparison to the solids after adsorption. Following spectroscopic results, it can be concluded that a strong interaction was established between risedronate ions and calcium ions at the apatitic surface. However, under these experimental conditions there is no nucleation of a distinct calcium risedronate salt and the apatite crystals retain their integrity.
authors.affiliation: CIRIMAT, INPT-CNRS-UPS, Université de Toulouse, Université Paul Sabatier, Toulouse, France; LPCME, CNRST-URAC 20, Faculté des Sciences Semlalia, University Cadi Ayyad, Marrakech, Morocco.
authors.forename: F
authors.initials: F
authors.lastname: Errassifi
authors.affiliation: CIRIMAT, INPT-CNRS-UPS, Université de Toulouse, Université Paul Sabatier, Toulouse, France. Electronic address: stephanie.sarda@iut-tlse3.fr.
authors.forename: S
authors.initials: S
authors.lastname: Sarda
authors.affiliation: LPCME, CNRST-URAC 20, Faculté des Sciences Semlalia, University Cadi Ayyad, Marrakech, Morocco.
authors.forename: A
authors.initials: A
authors.lastname: Barroug
authors.affiliation: School of Science & Engineering, Al Akhawayn University, Ifrane, Morocco.
authors.forename: A
authors.initials: A
authors.lastname: Legrouri
authors.affiliation: Laboratoire de Physique et d'Etude des Matériaux, ESPCI, Paris, France.
authors.forename: H
authors.initials: H
authors.lastname: Sfihi
authors.affiliation: CIRIMAT, INPT-CNRS-UPS, Université de Toulouse, ENSIACET, Toulouse, France.
authors.forename: C
authors.initials: C
authors.lastname: Rey
mesh_terms: D001031:Apatites / Q000737:chemistry*; D012968:Etidronic Acid / Q000031:analogs & derivatives* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D053758:Nanoparticles / Q000737:chemistry*; D000068296:Risedronic Acid; D013059:Spectrum Analysis, Raman
chemical_list: D001031:Apatites; D000068296:Risedronic Acid; D012968:Etidronic Acid
keywords: Adsorption; Bisphosphonate; Hydroxyapatite; Nanocrystalline apatite; Risedronate; Spectroscopy