Self setting calcium phosphate cements and methods for preparing and using them
First Claim
1. A method for making a calcium phosphate cement which self-sets at ambient temperatures comprising combining a calcium phosphate salt which is substantially free of tetracalcium phosphate with an additional source of calcium and an aqueous solution adjusted with base to maintain a pH of about 12.5 or above and having a phosphate concentration, above about 0.2 mol/L or higher in the absence of solid crystalline phosphoric acid.
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Accused Products
Abstract
The invention includes methods and compositions relating to calcium phosphate cements, which self-harden substantially to hydroxyapatite at ambient temperature when in contact with an aqueous medium. More specifically the cements comprise a combination of one or more sparingly soluble calcium phosphates other than tetracalcium phosphate with an aqueous solution adjusted with a base to maintain a pH of about 12.5 or above and having sufficient dissolved phosphate salt to yield a solution mixture with phosphate concentration equal to or greater than about 0.2 mol/L.
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Citations
29 Claims
- 1. A method for making a calcium phosphate cement which self-sets at ambient temperatures comprising combining a calcium phosphate salt which is substantially free of tetracalcium phosphate with an additional source of calcium and an aqueous solution adjusted with base to maintain a pH of about 12.5 or above and having a phosphate concentration, above about 0.2 mol/L or higher in the absence of solid crystalline phosphoric acid.
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5. A method for making a calcium phosphate cement which self-sets at ambient temperatures comprising combining a calcium phosphate salt which is substantially free of tetracalcium phosphate with an additional source of calcium and an aqueous solution adjusted with base to maintain a pH of about 12.5 or above.
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6. A method for making a calcium phosphate cement which self-sets at ambient temperatures comprising combining a calcium phosphate salt which is substantially free of tetracalcium phosphate with an additional source of calcium and an aqueous solution having a concentration of phosphate of about 0.2 mol/L or above, in the absence of solid crystalline phosphoric acid.
- 7. A calcium phosphate-containing composition which self-hardens substantially to hydroxyapatite at ambient temperature comprising a calcium phosphate salt which is substantially free of tetracalcium phosphate, an additional source of calcium, and an aqueous solution adjusted with base to maintain a pH of about 12.5 or above and having a phosphate concentration above about 0.2 mol/L or higher in the absence of solid crystalline phosphoric acid.
- 12. A calcium phosphate-containing composition, which self-hardens substantially to hydroxyapatite at ambient temperature, comprising a calcium phosphate salt which is substantially free of tetracalcium phosphate, an additional source of calcium and an aqueous solution adjusted with base to maintain a pH of about 12.5 or above.
- 13. A calcium phosphate-containing composition, which self-hardens substantially to hydroxyapatite at ambient temperature, comprising a calcium phosphate salt which is substantially free of tetracalcium phosphate, an additional source of calcium and an aqueous solution having a concentration of phosphate of about 0.2 mol/L or above, in the absence of solid crystalline phosphoric acid.
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28. A self-setting calcium phosphate bone cement comprising a mixture of (1) calcium phosphate salt which is substantially free of tetracalcium phosphate, (2) an additional source of calcium, and (3) an aqueous solution adjusted with base to maintain a pH of about 12.5 or above and having a phosphate concentration, above about 0.2 mol/L or higher in the absence of solid crystalline phosphoric acid whereby the cement can be used to bind non-self-setting calcium phosphate biomaterials such as porous and non-porous HA and β
- -tricalcium phosphate.
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29. An implant contructed in vitro for reconstruction of bone or dental tissue comprising a mixture of (1) calcium phosphate salt which is substantially free of tetracalcium phosphate, (2) an additional source of calcium, and (3) an aqueous solution adjusted with base to maintain a pH of about 12.5 or above and having a high phosphate concentration, in the absence of solid crystalline phosphoric acid whereby the mixture self-hardens substantially to hydroxyapatite at ambient temperature and can be shaped for desired applications.
Specification