Solubility of strontium-substituted apatite by solid titration.
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.
Pan
H B
HB
Department of Orthopaedics & Traumatology, The University of Hong Kong, Kowloon, Hong Kong.
Li
Z Y
ZY
Lam
W M
WM
Wong
J C
JC
Darvell
B W
BW
Luk
K D K
KD
Lu
W W
WW
D001826:Body Fluids; D002118:Calcium / Q000737:chemistry; D011232:Chemical Precipitation; D006863:Hydrogen-Ion Concentration; D006882:Hydroxyapatites / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry; D012995:Solubility; D017550:Spectroscopy, Fourier Transform Infrared; D013324:Strontium / Q000737:chemistry*; D013696:Temperature; D017186:Titrimetry / Q000379:methods*; D014961:X-Ray Diffraction
D006882:Hydroxyapatites; D010710:Phosphates; C076185:strontium hydroxyapatite; D002118:Calcium; D013324:Strontium