Magnesium ammonium phosphate cement composition

• US 7,115,163 B2
• Filed: 04/11/2005
• Issued: 10/03/2006
• Est. Priority Date: 07/03/2000
• Status: Expired due to Term

• Current Assignee: Kyphon SARL (Medtronic Plc)
• Original Assignee: Kyphon Incorporated
• Inventors: Zimmermann, Michael
• Primary Examiner(s): KOSLOW, CAROL M
• Application Number:
  US11/104,392
• Publication Number:
  US 20050246036A1
• Time in Patent Office: 540 Days
• Field of Search: None
• US Class Current: 106/35
• CPC Class Codes: A61B 17/00491 Surgical glue applicators surgical adhesives A61L24/00; two-component delivery syringes A61M5/19
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• CPC Class Codes: A61F 2002/30062 (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• CPC Class Codes: A61F 2002/30535 Special structural features of bone or joint prostheses not otherwise provided for
• CPC Class Codes: A61F 2002/4631 the prosthesis being specially adapted for being cemented
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61F 2250/0058 Additional features; Implant or prostheses properties not otherwise provided for
• CPC Class Codes: A61K 33/06 Aluminium, calcium or magnesium; Compounds thereof , e.g. clay
• CPC Class Codes: A61K 33/42 Phosphorus; Compounds thereof
• CPC Class Codes: A61K 45/06 Mixtures of active ingredients without chemical characterisation, e.g. antiphlogistics and cardiaca
• CPC Class Codes: A61K 6/17 Particle size
• CPC Class Codes: A61K 6/838 Phosphorus compounds, e.g. apatite
• CPC Class Codes: A61K 6/864 Phosphate cements apatite A61K6/838
• CPC Class Codes: A61K 6/867 Ammonium cements
• CPC Class Codes: A61L 24/0036 Porous materials, e.g. foams or sponges
• CPC Class Codes: A61L 24/02 containing inorganic materials
• CPC Class Codes: A61L 2430/02 for reconstruction of bones; weight-bearing implants
• CPC Class Codes: A61L 27/12 Phosphorus-containing materials, e.g. apatite
• CPC Class Codes: A61L 27/56 Porous materials, e.g. foams or sponges
• CPC Class Codes: A61P 19/00 Drugs for skeletal disorders
• CPC Class Codes: C04B 12/025 : Phosphates of ammonium or of the alkali or alkaline earth metals
• CPC Class Codes: C04B 14/22 : Glass ; Devitrified glass
• CPC Class Codes: C04B 14/26 : Carbonates
• CPC Class Codes: C04B 14/30 : Oxides other than silica ferrites C04B14/363
• CPC Class Codes: C04B 14/304 : Magnesia
• CPC Class Codes: C04B 14/366 : Phosphates, e.g. apatite
• CPC Class Codes: C04B 20/008 : Micro- or nanosized fillers, e.g. micronised fillers with particle size smaller than that of the hydraulic binder colloidal silica C04B14/062 ; silica fume C04B18/146
• CPC Class Codes: C04B 2103/0009 : Inorganic ammonium compounds
• CPC Class Codes: C04B 2111/00206 : Compositions defined by their elemental analysis
• CPC Class Codes: C04B 2111/00836 : for medical or dental applications
• CPC Class Codes: C04B 22/06 : Oxides, Hydroxides C04B22/0013 takes precedence
• CPC Class Codes: C04B 22/062 : of the alkali or alkaline-earth metals
• CPC Class Codes: C04B 22/064 : of the alkaline-earth metals
• CPC Class Codes: C04B 22/10 : containing carbon in the anion
• CPC Class Codes: C04B 22/124 : Chlorides of ammonium or of the alkali or alkaline earth metals, e.g. calcium chloride
• CPC Class Codes: C04B 22/126 : Fluorine compounds, e.g. silico-fluorine compounds
• CPC Class Codes: C04B 22/142 : Sulfates
• CPC Class Codes: C04B 22/143 : Calcium-sulfate
• CPC Class Codes: C04B 22/16 : containing phosphorus in the anion, e.g. phosphates
• CPC Class Codes: C04B 24/10 : Carbohydrates or derivatives thereof
• CPC Class Codes: C04B 24/282 : Polyurethanes; Polyisocyanates
• CPC Class Codes: C04B 28/34 : containing cold phosphate binders
• CPC Class Codes: C04B 28/344 : the phosphate binder being present in the starting composition solely as one or more phosphates
• CPC Class Codes: C04B 28/346 : the phosphate binder being present in the starting composition as a mixture of free acid and one or more phosphates
• CPC Class Codes: C04B 28/348 : the starting mixture also containing one or more reactive oxides

Abstract

This invention relates to a cement, which comprises in its main phase of microcrystalline magnesium ammonium phosphate and nanoapatite after hardening and thus at the same time has considerable strength. The material is biologically degradable and is suitable for application in tooth cements, as bone replacement, as bone filler, as bone cement or as bone adhesive.

Claims

1. A method of repairing or replacing bone comprising:

a) combining a powder mixture with a mixing liquid to obtain a cement paste, the powder mixture comprising molar quantities of the components calcium (Ca), magnesium (Mg) and orthophosphate (P) in the mixture in the ranges 1<

Ca/P<

1.5 and Mg/P<

0.5, an amount of strontium to cause the cement paste to expand during hardening, and an ammonium salt; and

b) applying the paste to or into a target zone of a bone.

2. The method of claim 1, wherein the powder mixture comprises alpha-TCP, beta-TCP, MgHPO₄×

3H₂O, KH₂PO₄, Na₂HPO₄, SrCO₃ and ammonium salt.

3. The method of claim 1, wherein the mixing liquid is water or an aqueous solution.

4. The method of claim 3, wherein said aqueous solution comprises an ammonium salt.

5. The method of claim 1, further comprising adjusting the expansivity of the cement paste by adjusting the relative proportion of strontium.

6. The method of claim 5, wherein the strontium is present as SrCO₃ in a range of 0.01 to 10 weight percent based on a total weight of the preparation.

7. The method of claim 5, wherein the strontium is present as SrCO₃ in a range of 0.1 to 5 weight percent based on a total weight of the preparation.

8. The method of claim 1, wherein the cement paste is resorbable into a human body.

9. The method of claim 1, wherein the paste that is applied to or into the target zone is allowed to harden at the target zone to form microcrystalline magnesium ammonium phosphate.

10. The method of claim 1, wherein the cement paste is injected into the target zone.

11. The method of claim 1, wherein the method is part of a medical procedure selected from the group consisting of bone replacement, bone augmentation and bone regeneration.

12. The method of claim 1, wherein the cement paste is selected from the group consisting of bone filler, bone adhesive and tooth cement.

13. A composition comprising:

an ammonium salt; and

a powder mixture comprising molar quantities of the components calcium (Ca), magnesium (Mg) and orthophosphate (P) in a mixture in the ranges 1<

Ca/P<

1.5 and Mg/P<

0.5, the powder mixture further comprising strontium in an amount of weight percent of the composition such that when the powder mixture and the ammonium salt are combined, the ammonium salt and the powder mixture form a magnesium ammonium phosphate cement preparation, wherein the expansivity of the cement preparation is adjusted by the proportion of the strontium added.

14. The composition of claim 13, wherein the strontium is in the form SrCO₃, and the amount of weight percent of the composition is in the range of 0.01 to 10.