HIGUCHI MODEL APPLIED TO IONS RELEASE FROM HYDROXYAPATITES.

In this study, the ions release of physiological elements from pure stoichiometric hydroxyapatite, HAP, and from multi-substituted hydroxyapatite, ms-HAPs, containing 1.5%Mg, 0.2%Zn, 0.2%Si and 5 %Sr, noted HAPc-5%Sr, and from HAPc-10%Sr, in water and in simulated body fluid, SBF, was studied by inductively coupled plasma optical emission spectrometry, ICP-OES, both in static and simulated dynamic regimes. The HAP and ms-HAP nanoparticles, NPs, were prepared by wet chemical precipitation and lyophilized powders were physicochemical characterized as presented elsewhere. The in vitro cations and anions release mechanism was investigated by applying a modified Higuchi model, which fits well the experimental results, particularly for simulated dynamic conditions. The predominant role of diffusion in the release of ions from the hydroxyapatites was confirmed. The sustained ions release from these nanomaterials recommends the investigated ms-HAPs for therapeutic applications. [ABSTRACT FROM AUTHOR]