Calcium phosphate hydroxyapatite precursor and methods for making and using the same
First Claim
1. A calcium phosphate-containing composition, which self-hardens substantially to hydroxyapatite at ambient temperature when in contact with an aqueous medium, comprising tetracalcium phosphate and at least one other sparingly soluble calcium phosphate compound, wherein the tetracalcium phosphate is prepared from a starting mixture of one or more sources of calcium, phosphorous and oxygen which mixture has a calcium to phosphorous ratio of less than 2.
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Accused Products
Abstract
Calcium phosphate compositions that are particularly useful and unique as orthopedic and dental cements and remineralizers, as well as methods and kits for their use, and the resulting products are disclosed. The compositions comprise tetracalcium phosphate which has been prepared from a mixture with a calcium to phosphorous ratio of less than 2, or prepared and maintained under substantially anhydrous conditions prior to use or, preferably, both. The novel compositions are converted substantially to hydroxyapatite upon setting, are substantially gradually resorbable and replaced by bone when implanted in contact with living bony tissue, and offer distinct advantages in terms of cement strength, setting time and reliability and other properties.
270 Citations
62 Claims
- 1. A calcium phosphate-containing composition, which self-hardens substantially to hydroxyapatite at ambient temperature when in contact with an aqueous medium, comprising tetracalcium phosphate and at least one other sparingly soluble calcium phosphate compound, wherein the tetracalcium phosphate is prepared from a starting mixture of one or more sources of calcium, phosphorous and oxygen which mixture has a calcium to phosphorous ratio of less than 2.
- 4. A calcium phosphate-containing composition, which self-hardens substantially to hydroxyapatite at ambient temperature when in contact with an aqueous medium, comprising tetracalcium phosphate and at least one other sparingly soluble calcium phosphate compound, wherein the tetracalcium phosphate is prepared and maintained under substantially anhydrous conditions prior to its contact with the aqueous medium in combination with the other sparingly soluble calcium phosphate compound.
- 7. A calcium phosphate-containing composition, which self-hardens substantially to hydroxyapatite at ambient temperature when in contact with an aqueous medium, comprising tetracalcium phosphate and at least one other sparingly soluble calcium phosphate compound, wherein the tetracalcium phosphate is free of calcium oxide.
- 9. A calcium phosphate-containing composition, which self-hardens substantially to hydroxyapatite at ambient temperature when in contact with an aqueous medium, comprising tetracalcium phosphate and at least one other sparingly soluble calcium phosphate compound, wherein the tetracalcium phosphate is free of surface hydroxyapatite prior to use.
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11. A calcium phosphate-containing composition, which self-hardens substantially to hydroxyapatite at ambient temperature when in contact with an aqueous medium, comprising tetracalcium phosphate and at least one other sparingly soluble calcium phosphate compound, wherein the tetracalcium phosphate is prepared from a starting mixture of one or more sources of calcium, phosphorous and oxygen which has a calcium to phosphorous ratio of less than 2;
- and wherein the tetracalcium phosphate is prepared and maintained under substantially anhydrous conditions prior to its contact with the aqueous medium in combination with the other sparingly soluble calcium phosphate compound.
- View Dependent Claims (12, 13, 14)
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15. A calcium phosphate-containing composition, which self-hardens substantially to hydroxyapatite at ambient temperature when in contact with an aqueous medium, comprising tetracalcium phosphate and at least one other sparingly soluble calcium phosphate compound, wherein the tetracalcium phosphate is comminuted tetracalcium phosphate having an average particle size for at least about 10% of the particles of about 15μ
- or less and which is free of both impurity calcium oxide and surface hydroxyapatite.
- View Dependent Claims (16)
- 29. A calcium phosphate bone cement which self-hardens substantially at ambient temperature and is substantially resorbable when implanted in contact with living bone comprising tetracalcium phosphate and at least one other sparingly soluble calcium phosphate wherein the tetracalcium phosphate is prepared from a starting mixture of one or more sources of calcium, phosphorous and oxygen which has a calcium to phosphorous ratio of less than 2.
- 31. A calcium phosphate bone cement which self-hardens substantially at ambient temperature and is substantially resorbable when implanted in contact with living bone comprising tetracalcium phosphate and at least one other sparingly soluble calcium phosphate wherein the tetracalcium phosphate is prepared and maintained under substantially anhydrous conditions prior to its contact with the aqueous medium in combination with the other sparingly soluble calcium phosphate compound.
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33. A calcium phosphate bone cement which self-hardens substantially at ambient temperature and is substantially resorbable when implanted in contact with living bone comprising tetracalcium phosphate and at least one other sparingly soluble calcium phosphate wherein the tetracalcium phosphate is prepared from a starting mixture of one or more sources of calcium, phosphorous and oxygen which has a calcium to phosphorous ratio of less than 2;
- and wherein the tetracalcium phosphate is prepared and maintained under substantially anhydrous conditions prior to its contact with the aqueous medium in combination with the other sparingly soluble calcium phosphate compound.
- View Dependent Claims (34, 35, 36, 37, 39, 45, 47)
- 48. An improved method for preparing a tetracalcium phosphate based calcium phosphate-containing composition comprising combining tetracalcium phosphate and at least one other sparingly soluble calcium phosphate, wherein the improvement comprises employing tetracalcium phosphate prepared from a mixture of one or more sources of calcium, phosphorus and oxygen which has a calcium to phosphorous ratio of less than 2.
- 51. An improved method for preparing a tetracalcium phosphate based calcium phosphate-containing composition comprising combining tetracalcium phosphate and at least one other sparingly soluble calcium phosphate wherein the improvement comprises preparing and maintaining the tetracalcium phosphate under substantially anhydrous conditions prior to its contact with the aqueous medium in combination with the other sparingly soluble calcium phosphates.
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54. An improved method for preparing a tetracalcium phosphate based calcium phosphate-containing composition comprising combining tetracalcium phosphate and at least one other sparingly soluble calcium phosphate compound wherein the improvement comprises employing tetracalcium phosphate prepared from a mixture of one or more sources of calcium, phosphorous and oxygen which has a calcium to phosphorous ratio of less than 2;
- and wherein the tetracalcium phosphate is prepared and maintained under substantially anhydrous conditions prior to its contact with the aqueous medium in combination with the other sparingly soluble calcium phosphate compounds.
- View Dependent Claims (56)
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55. An improved method for preparing a calcium phosphate cement which self-hardens substantially at ambient temperature comprising combining tetracalcium phosphate and at least one other sparingly soluble calcium phosphate compound wherein the improvement comprises employing tetracalcium phosphate prepared from a starting mixture of one or more sources of calcium, phosphorous and oxygen which has a calcium to phosphorous ratio of less than 2;
- and preparing and maintaining the tetracalcium phosphate under substantially anhydrous conditions prior to its contact with the aqueous medium in combination with the other sparingly soluble calcium phosphate compound.
- View Dependent Claims (57)
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58. A paste comprising an aqueous mixture of tetracalcium phosphate and at least one other sparingly soluble calcium phosphate which aqueous mixture hardens into a cement at an ambient temperature wherein the tetracalcium phosphate is prepared from a starting mixture of one or more sources of calcium, phosphorous and oxygen which has a calcium to phosphorous ratio of less than 2.
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59. A paste comprising an aqueous mixture of tetracalcium phosphate and at least one other sparingly soluble calcium phosphate which aqueous mixture hardens into a cement at an ambient temperature wherein the tetracalcium phosphate is prepared and maintained under substantially anhydrous conditions prior to its contact with the aqueous medium in combination with the other sparingly soluble calcium phosphate compounds.
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60. A slurry comprising an aqueous mixture of tetracalcium phosphate and at least one other sparingly soluble calcium phosphate, both calcium phosphates being present in the slurry in excess such that hydroxyapatite is substantially continuously precipitated from the slurry at ambient temperature, wherein the tetracalcium phosphate is prepared from a starting mixture of one or more sources of calcium, phosphorous and oxygen which has a calcium to phosphorous ratio of less than 2.
- 61. A slurry comprising an aqueous mixture of tetracalcium phosphate and at least one other sparingly soluble calcium phosphate, both calcium phosphates being present in the slurry in excess such that hydroxyapatite is substantially continuously precipitated from the slurry at an ambient temperature, wherein the tetracalcium phosphate is prepared and maintained under substantially anhydrous conditions prior to its contact with the aqueous medium in combination with the other sparingly soluble calcium phosphate compounds.
Specification