Gallium-doped phosphocalcic compounds

1. A gallium-doped phosphocalcic compound of formula (I):

Ca (10.5-1.5x) Ga x (PO 4 ) 7   (I)

having a structure close to β-tricalcium phosphate (β-TCP),

wherein 0<x<1

and the salts, hydrates and mixtures thereof.

2. The gallium-doped phosphocalcic compound according to claim 1 , wherein in formula (I) 0<x≦0.85.

3. The gallium-doped phosphocalcic compound according to claim 1 , wherein the 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 9.27 Ga 0.82 (PO 4 ) 7 .

4. The gallium-doped phosphocalcic compound according to claim 1 , wherein the compound of formula (I) crystallises 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°.

5. A solid state process for the manufacture of a gallium-doped phosphocalcic compound of formula (I) according to claim 1 comprising the following steps:

(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.

6. The solid state process according to claim 5 , wherein the calcium phosphate used in step (a) is DCPA, DCPD or a mixture thereof.

7. The solid state process according to claim 5 , wherein the gallium compound used in step (a) is gallium oxide.

8. A method for the preparation of a biomaterial, the method comprising incorporating a gallium-doped phosphocalcic compound according to claim 1 into the biomaterial.

9. The method of claim 8 , wherein the biomaterial is a self-setting calcium phosphate cement (CPC).