Galliated calcium phosphate biomaterials

1. A galliated calcium-phosphate biomaterial comprising a compound selected from a gallium-doped phosphocalcic compound of formula (1):

Ca (10.5-1.5x) Ga x (PO 4 ) 7   (1)

wherein 0≦x≦1 and

characterized in that it crystallizes at least partially in the space group R3c with cell parameters varying in the following range, as a function of the Ga content: a=10.31-10.44 Å, c=37.15-37.5 Å, α=90°; β=90° and γ=120° and/or

characterized by a Ca/P ratio comprised between 1.44 and 1.67 and an X-ray powder diffraction broad lines at 2θ˜26° (medium) and ˜32° (strong),

and hydrates thereof.

2. The galliated calcium phosphate biomaterial according to claim 1 , wherein in formula (I) 0<x≦0.85.

3. The galliated calcium phosphate biomaterial according to claim 1 , wherein the gallium-doped phosphocalcic compound of formula (I) is selected from the group consisting of Ca 10.125 Ga 0.25 (PO 4 ) 7 ; Ca 9.75 Ga 0.5 (PO 4 ) 7 ; Ca 9.375 Ga 0.75 (PO 4 ) 7 ; and Ca 9.5 Ga 0.82 (PO 4 ) 7 .

4. The galliated calcium-phosphate biomaterial comprising a gallium-doped phosphocalcic compound according to claim 1 , obtainable by a solid-state process comprising the steps of:

(a) contacting calcium phosphate with calcium carbonate in presence of a suitable quantity of a gallium compound;

(b) sintering the mixture to form a gallium-doped phosphocalcic compound; and

(c) recovering the gallium-doped phosphocalcic compound and having a gallium content of up to 5.3% by weight.

5. A galliated calcium-phosphate biomaterial comprising a gallium-doped phosphocalcic compound according to claim 1 , obtainable by a process comprising the steps consisting of:

(a) preparing an aqueous solution containing a calcium compound and an appropriate quantity of a gallium compound;

(b) adjusting the pH of the solution obtained in step (a) to a value of 8.5 to 12, if necessary;

(c) adding to said solution an appropriate quantity of a phosphate compound;

(d) precipitating a gallium-doped phosphocalcic compound by adjusting the pH of said solution to a value of 7.0 to 12; and

(e) separating the precipitated gallium-doped phosphocalcic compound from the solution

and having a (Ca+Ga)/P molar ratio in the range of 1.3-1.67, and a gallium content up to 4.5% by weight.

6. A galliated calcium-phosphate biomaterial comprising a gallium-doped phosphocalcic compound according to claim 1 , obtainable by a solid/liquid process comprising the steps of:

(a) suspending calcium phosphate in an aqueous gallium solution, the pH of which is adjusted to a value of 8 to 9;

(b) stirring the resulting suspension at room temperature; and

(c) separating the gallium-doped phosphocalcic compound from the solution and having a (Ca+Ga)/P molar ratio in the range of 1.3-1.67 and a gallium content up to 0.65% by weight.

7. The galliated calcium phosphate biomaterial according to claim 5 , comprising a phosphocalcic compound characterized by a Ca/P ratio comprised between 1.44 and 1.67 and an X-ray powder diffraction broad lines at 2θ˜26° (medium) and ˜32° (strong).

8. The galliated calcium phosphate biomaterial according to claim 6 , comprising a phosphocalcic compound characterized by a Ca/P ratio comprised between 1.44 and 1.67 and an X-ray powder diffraction broad lines at 2θ˜26° (medium) and ˜32° (strong).

9. The galliated calcium-phosphate biomaterial according to claim 1 , wherein the material is self-setting.

10. The galliated calcium-phosphate biomaterial according to claim 1 , further comprising a polymer.

11. A process for the manufacture of a galliated calcium phosphate biomaterial according to claim 9 , comprising the steps of:

providing an appropriate amount of TCP(Ca 3 (PO 4 ) 2 );

mixing the TCP with appropriate amounts of one or more gallium doped phosphocalcic compounds and optionally other additives; and

grinding of the components to form a solid phase of a calcium phosphate cement.

12. An implant comprising the galliated calcium phosphate biomaterial according to claim 1 .

13. A process for the manufacture of the implant according to claim 12 comprising the step of:

(i) mixing the self-setting galliated calcium phosphate biomaterial according to claim 9 with an appropriate amount of an aqueous liquid phase to obtain a cement paste; and

(ii) forming the cement paste into an implant.

14. A kit comprising the galliated calcium phosphate biomaterial according to claim 1 in combination with a fluid component.

15. A method for filling a bony or tooth defect comprises using the galliated calcium phosphate biomaterial according claim 1 .