Effects of magnesium on calcium phosphate formation.
All biological calcium phosphates form in various neutral aqueous solutions containing [CaCl2] = 1 or 3 mM, [MgCl2] = 0-9 mM, [Na2HPO4] = 0.1-90 mM and NaCl (total 300 mosM) kept quiescently at 37 degrees C for 21 days. In all solutions containing 1 mM Ca and in solutions with [Ca] = 3 mM and [PO4] less than 10 mM, heterogeneous nucleation of octa-calcium phosphate (for Mg/Ca less than or equal to 1) or brushite (for Mg/Ca greater than 1) was observed; the former transforming to apatite with time. In contrast, homogeneous nucleation of an unstable amorphous calcium magnesium phosphate occurred in solutions with [Ca] = 3 mM and [PO4] greater than or equal to 10 mM, transforming to apatite, to brushite, and to whitlockite (and newberyite) depending on Mg/Ca and [PO4] values.
Cheng
P T
PT
University of Toronto, Ont., Canada.
Grabher
J J
JJ
LeGeros
R Z
RZ
D001031:Apatites; D002130:Calcium Phosphates; D011232:Chemical Precipitation; D003460:Crystallization; D017886:Durapatite; D006863:Hydrogen-Ion Concentration; D006882:Hydroxyapatites; D008274:Magnesium / Q000494:pharmacology*; D017616:Magnesium Compounds; D010710:Phosphates; D012996:Solutions; D014961:X-Ray Diffraction
D001031:Apatites; D002130:Calcium Phosphates; D006882:Hydroxyapatites; D017616:Magnesium Compounds; D010710:Phosphates; D012996:Solutions; C485828:alpha-tricalcium phosphate; C485830:tetracalcium phosphate; C022045:octacalcium phosphate; C021767:whitlockite; C015335:calcium magnesium phosphate; C030781:magnesium phosphate; C485838:calcium phosphate, monobasic, anhydrous; D017886:Durapatite; C020243:calcium phosphate; D008274:Magnesium; C485829:calcium phosphate, dibasic, anhydrous; C494366:calcium phosphate, dibasic, dihydrate