Patent ID: 7473312

Claim:
A self setting calcium phosphate cement comprising: (i) a powdered component selected from the group consisting of: (a) calcium phosphate, dicalcium phosphate anhydrous, dicalcium phosphate dihydrate, α-tricalcium phosphate, tetracalcium phosphate, hydroxyapatite, octacalcium phosphate, substituted forms thereof, or mixtures thereof; (b) a carbonate, silicate, nitrate, oxide, sulphate or salt of calcium, zirconium, aluminium, titanium or silicon, or mixtures thereof; and (c) mixtures of (a) and (b), said powdered component having an average particle size d 50 of less than 15 μm, and (ii) a calcium phosphate based powder selected from the group consisting of tetracalcium phosphate, α-tricalcium phosphate, hydroxyapatite, monocalcium phosphate monohydrate, monocalcium phosphate anhydrous and mixtures thereof, said powder having an average particle size d 50 greater than that of the powdered component, said powdered component and said calcium phosphate based powder being suspended in water containing a dissolved zeta potential increasing additive in an amount of from 0.1 to 2 Mol per liter of water and in sufficient quantity to increase the zeta potential of the suspended particles to at least −30 mV, and wherein the zeta potential increasing additive is chosen to be compatible with the setting pH of the same calcium phosphate cement without the zeta potential increasing additive.