(US7695740) The invention claimed is: 1. A synthetic calcium phosphate-based biomedical material comprising silicon and a trivalent cation wherein the material comprises a compound having the chemical formula: Ca10-yMy(PO4)6-x(SiO4)x(OH)2-x+y where M is a trivalent cation, 0<x<1.3 and 0<y<1.3 and wherein the trivalent cation is selected from one or more of yttrium, scandium, aluminum and the Lanthanide elements. 2. The biomedical material according to claim 1, wherein the calcium phosphate-based biomedical material comprises hydroxyapatite or apatite. 3. The biomedical material according to claim 1, wherein 0<x<1.1. 4. The biomedical material according to claim 3, wherein 0.5<x<1.1. 5. The biomedical material according to claim 1, wherein 0<y<1.1. 6. The biomedical material according to claim 5, wherein 0.5<y<1.1. 7. The biomedical material according to claim 1, wherein x >= y. 8. The biomedical material according to claim 1, wherein y >= x. 9. The biomedical material according to claim 1, wherein the phase purity of the biomedical material, as measured by X-ray diffraction, is at least 95%. 10. The biomedical material according to claim 1, wherein the biomedical material comprises one or more secondary phases. 11. The biomedical material according to claim 10, wherein the secondary phases comprise one or more of tricalcium phosphate, alpha or beta polymorphs thereof, calcium silicate, tetracalcium phosphate, calcium carbonate, calcium oxide, monetite, brushite, calcium pyrophosphate and octacalcium phosphate. 12. The biomedical material according to claim 1, wherein the trivalent cation is yttrium. 13. A synthetic bone material, bone implant, bone graft, bone substitute, bone scaffold, filler, coating or cement comprising a biomedical material as defined in claim 1. 14. A process for the synthesis of a calcium phosphate-based material of claim 1 comprising silicon and a trivalent cation, the process comprising: providing calcium or a calcium-containing compound, a trivalent cation-containing compound, a phosphorus-containing compound and a silicon-containing compound; and forming a precipitate by reacting the compounds in an aqueous phase at an alkali pH. 15. The process according to claim 14, wherein the calcium phosphate-based material comprises hydroxyapatite or apatite. 16. The process according to claim 14, wherein the calcium-containing compound comprises a calcium salt. 17. The process according to claim 16, wherein the calcium salt is selected from one or more of calcium hydroxide, calcium chloride, calcium nitrate and/or calcium nitrate hydrate. 18. The process according to claim 14, wherein the trivalent cation-containing compound comprises a compound of yttrium. 19. The process according to claim 18, wherein the yttrium compound is selected from one or both of yttrium chloride and/or yttrium nitrate. 20. The process according to claim 18, wherein yttrium is present in the material in an amount of up to 13 weight percent. 21. The process according to claim 18, wherein yttrium is present in the material in an amount of up to 20 weight percent. 22. The process according to claim 14, wherein the phosphorus-containing compound is selected from one or both of a phosphate salt and/or a phosphoric acid. 23. The process according to claim 22, wherein the phosphorus-containing compound is selected from one or both of ammonium phosphate and/or phosphoric acid. 24. The process according to claim 14, wherein the silicon-containing compound comprises a silicate. 25. The process according to claim 24, wherein the silicate is selected from one or both of tetraethyl orthosilicate (TEOS) and/or silicon acetate. 26. The process according to claim 24, wherein the silicate is present in the material in an amount of up to 13 weight percent. 27. The process according to claim 24, wherein the silicate is present in the material in an amount of up to 20 weight percent. 28. The process according to claim 14, wherein the pH is from 8 to 13. 29. The process according to claim 28, wherein the pH is from 10 to 12. 30. The process according to claim 14, wherein an alkali is added to adjust the pH of the solution to the desired pH. 31. The process according to claim 30, wherein the alkali is ammonium hydroxide or concentrated ammonia. 32. The process according to claim 14, wherein after the precipitate has been formed it is dried, heated and/or sintered. 33. The process according to claim 32, wherein the precipitate is heated and/or sintered to a temperature in the range of from 800 deg. C. to 1500 deg. C. 34. The process according to claim 33, wherein the precipitate is heated and/or sintered to a temperature in the range of from 1000 deg. C. to 1350 deg. C., preferably from 1200 deg. C. to 1300 deg. C. 35. The process according to claim 14, wherein the silicon-containing and the trivalent cation-containing compounds are supplied in equimolar quantities with respect to the amount of silicon and the quantity of the trivalent cation. 36. The process according to claim 14, wherein the silicon-containing compound is supplied in a greater quantity than the trivalent cation compound with respect to the quantity of silicon and the quantity of the trivalent cation. 37. The process according to claim 14, wherein the silicon-containing compound is supplied in a lesser quantity than the trivalent cation compound with respect to the quantity of silicon and the quantity of the trivalent cation. 38. A method of stabilizing a silicon-substituted calcium phosphate material of claim 1, characterized by substituting a trivalent cation into the lattice. 39. The method according to claim 38, wherein the calcium phosphate material comprises hydroxyapatite or apatite. 40. The method according to claim 38, wherein the trivalent cation is yttrium. 41. The biomedical material according to claim 1, wherein the phase purity of the biomedical material, as measured by X-ray diffraction, is at least 97%. 42. The biomedical material according to claim 1, wherein the phase purity of the biomedical material, as measured by X-ray diffraction, is at least 99%. 43. The process according to claim 18, wherein yttrium is present in the material in an amount of up to 12 weight percent. 44. The process according to claim 24, wherein the silicate is present in the material in an amount of up to 12 weight percent. 45. The biomedical material of claim 1, wherein the silicate is present in the material in an amount of up to 12 weight percent. 46. The biomedical material according to claim 1, wherein the trivalent cation is yttrium. 47. The process of claim 24, wherein the silicate is present in the material in an amount of greater than 5.3 weight percent and up to 13 weight percent. 48. The process of claim 24, wherein the silicate is present in the material in an amount of greater than 5.3 weight percent and up to 12 weight percent. 49. The process of claim 24, wherein the silicate is present in the material in an amount of greater than 13 weight percent and up to 20 weight percent. 50. The biomedical material of claim 1, wherein the silicate is present in the material in an amount of greater than 5.3 weight percent and up to 13 weight percent. 51. The biomedical material of claim 1, wherein the silicate is present in the material in an amount of greater than 5.3 weight percent and up to 12 weight percent. 52. The biomedical material of claim 1, wherein the silicate is present in the material in an amount of greater than 13 weight percent and up to 20 weight percent.
最新评论
暂无评论。