Calcium phosphate/sulphate-based bone implant composition

Abstract

A bone implant composition, the composition comprising calcium sulphate and slowly soluble sources of calcium, orthophosphate and hydroxyl ions. The composition may be provided in powder or granulated form.

1 . A bone implant composition characterised in that the composition comprises calcium sulphate and slowly soluble sources of calcium, orthophosphate and hydroxyl ions.  
     
     
         2 . A composition according to  claim 1 , characterised in that the source of the ions is provided by compounds which are slowly soluble in water.  
     
     
         3 . A composition according to  claim 2 , characterised in that water solubility of the compounds at room temperature is less than 5 g per litre.  
     
     
         4 . A composition according to  claim 3 , characterised in that water solubility of the compounds at room temperature is less than 1 g per litre.  
     
     
         5 . A composition according to  claim 4 , characterised in that water solubility of the compounds at room temperature is less than 0.1 g per litre.  
     
     
         6 . A composition according to any of the preceding claims, characterised in that the source of the calcium ions is the calcium sulphate alone.  
     
     
         7 . A composition according to any of  claims 1  to  5 , characterised in that the source of the calcium ions is provided by one or more of: calcium carbonate, calcium phosphate, calcium oxide, calcium fluoride, calcium citrate, calcium stearate, or dolomite.  
     
     
         8 . A composition according to any of the preceding claims, characterised in that the calcium sulphate is in the form of dehydrate, hemi-hydrate, soluble anhydrite or insoluble anhydrite.  
     
     
         9 . A composition according to any of the preceding claims, characterised in that the ratio of calcium sulphate to all other compounds in the composition is between 0.2 and 2 parts by weight.  
     
     
         10 . A composition according to any of the preceding claims, characterised in that the composition comprises a medicament.  
     
     
         11 . A composition according to  claim 10 , characterised in that the medicament is in an effective therapeutic amount.  
     
     
         12 . A composition according to  claim 10  or  claim 11 , characterised in that the medicament comprises any of: an antibiotic, an anti-cancer agent, or bone morphogenic protein.  
     
     
         13 . A composition according to any of the preceding claims, characterised in that the source of orthophosphate ions is one or more of: hydroxyapatite, alpha tricalcium phosphate, beta tricalcium phosphate, dicalcium phosphate, tetracalcium phosphate or magnesium orthophosphate.  
     
     
         14 . A composition according to any of the preceding claims, characterised in that the source of orthophosphate ions is in the form of a micro-porous granular solid.  
     
     
         15 . A composition according to  claim 14 , characterised in that the granules have a particle size in the range 0.2-5.00 mm.  
     
     
         16 . A composition according to any of the preceding claims, characterised in that the source of the hydroxyl ions may be one or more of: calcium oxide, insoluble anhydrite, calcium hydroxide, magnesium oxide, magnesium hydroxide, zinc oxide, zinc hydroxide, or basic magnesium carbonate.  
     
     
         17 . A composition according to any of the preceding claims, characterised in that in the composition the ratio of basicity to orthophosphate is between 0.0 and 1.0 molar.  
     
     
         18 . A composition according to any of the preceding claims, characterised in that the composition is in the form of a powder which can be mixed with water or an aqueous solution to form a usable paste.  
     
     
         19 . A composition according to any of  claims 1  to  17 , characterised in that the composition is in the form of granules or pellets.  
     
     
         20 . A composition according to  claim 19 , characterised in that the composition is formed into pellets using a tablet press.  
     
     
         21 . A method of forming a bone graft, characterised in that the method comprises using a bone implant composition according to any of the preceding claims.  
     
     
         22 . A method according to  claim 21  when dependent on  claim 18 , characterised in that when in powder form the composition is mixed with water or an aqueous solution to form a putty or paste prior to application.  
     
     
         23 . A method according to  claim 22 , characterised in that the putty or paste is applied to a surgical site by a suitable applicator such as a syringe.  
     
     
         24 . A method according to  claim 22 , characterised in that the putty or paste is applied to a mould and allowed to set prior to presentation to the surgical site.  
     
     
         25 . A method according to  claim 21  when dependent on  claim 19  or  claim 20 , characterised in that when the composition is in the form of granules or pellets, the granules or pellets can be packed into a bone cavity.  
     
     
         26 . Any novel subject matter or combination including novel subject matter disclosed herein, whether or not within the scope of or relating to the same invention as any of the preceding claims.