Solubility of strontium-substituted apatite by solid titration

Acta Biomater. 2009 Jun;5(5):1678-85. doi: 10.1016/j.actbio.2008.11.032. Epub 2008 Dec 24.

Abstract

Solid titration was used to explore the solubility isotherms of partially (Srx-HAp, x=1, 5, 10, 40, 60 mol.%) and fully substituted strontium hydroxyapatite (Sr-HAp). Solubility increased with increasing strontium content. No phase other than strontium-substituted HAp, corresponding to the original titrant, was detected in the solid present at equilibrium; in particular, dicalcium hydrogen phosphate was not detected at low pH. The increase in solubility with strontium content is interpreted as a destabilization of the crystal structure by the larger strontium ion. Carbonated HAp was formed in simulated body fluid containing carbonate on seeding with Sr10-HAp, but the precipitate was strontium-substituted on seeding with Sr-HAp. Strontium-substituted HAp might be usable as a template for the growth of new bone, since nucleation appears to be facilitated.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Body Fluids
  • Calcium / chemistry
  • Chemical Precipitation
  • Hydrogen-Ion Concentration
  • Hydroxyapatites / chemistry*
  • Phosphates / chemistry
  • Solubility
  • Spectroscopy, Fourier Transform Infrared
  • Strontium / chemistry*
  • Temperature
  • Titrimetry / methods*
  • X-Ray Diffraction

Substances

  • Hydroxyapatites
  • Phosphates
  • strontium hydroxyapatite
  • Calcium
  • Strontium