US2007224245A1PendingUtilityA1

Poly (diol co-citrate) hydroxyapatite composite for tissue engineering and orthopaedic fixation devices

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Assignee: UNIV NORTHWESTERNPriority: Feb 8, 2006Filed: Feb 8, 2007Published: Sep 27, 2007
Est. expiryFeb 8, 2026(expired)· nominal 20-yr term from priority
Inventors:Guillermo A. AmeerHongjin QiuJian Yang
A61L 31/127A61L 31/123A61L 31/06A61L 27/425A61L 27/18A61L 2430/02A61L 27/427A61L 31/148A61L 27/46A61L 27/12A61L 27/58A61L 31/121A61L 31/026
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Claims

Abstract

The present invention is directed to a novel poly (diol citrates)-based bioceramic composite materials created using completely biodegradable and a bioceramic material polymers that may be used in implantable devices. More specifically, the specification describes methods and compositions for making and using bioceramic composites comprised of citric acid copolymers and a bioceramic material.

Claims

exact text as granted — not AI-modified
1 . A composition comprising a composite of: 
 a) a citric acid polyester having the generic formula (A-B-C) n , wherein 
 A is a linear aliphatic dihydroxy monomer;  
 B is citric acid,  
 C is a linear aliphatic dihydroxy monomer, and  
 n is an integer greater than 1; and  
   b) a bioceramic used for implantable tissue devices, wherein less than 75 wt. % weight ratio of said composition comprises said bioceramic.    
   
   
       2 . The composition of  claim 1 , wherein A is a linear diol comprising between about 2 and about 20 carbons.  
   
   
       3 . The composition of  claim 1 , wherein C is a linear diol comprising between about 2 and about 20 carbons.  
   
   
       4 . The composition of  claim 1 , wherein both A and C are the same linear diol.  
   
   
       5 . The composition of  claim 4 , wherein said linear diol is 1, 8, octanediol.  
   
   
       6 . The composition of  claim 1 , wherein A and C are different linear diols.  
   
   
       7 . The composition of  claim 5 , wherein said linear aliphatic dihydroxy poly 1,8-octanediol co-citric acid.  
   
   
       8 . The composition of  claim 5 , wherein said linear aliphatic dihydroxy poly 1,10-decanediol co-citric acid.  
   
   
       9 . The method of  claim 1 , wherein said bioceramic is selected from the group consisting of calcium phosphate bioceramics, alumina-based bioceramics; zirconia-based bioceramics; silica-based bioceramics, and pyrolytic carbon-based bioceramics.  
   
   
       10 . The method of  claim 9 , wherein said bioceramic is a calcium phosphate bioceramic at a weight percentage of from 30 wt. % to about 75 wt. % of the total weight of the composition.  
   
   
       11 . The method of  claim 10 , wherein said bioceramic is hydroxyapatite (HA) at a weight percentage of between about 40 wt. %±5 wt. % to about 70 wt. %±5 wt. % HA to 35 wt. %±5 wt. % to about 25 wt. %±5 wt. % citric acid polyester.  
   
   
       12 . The composition of  claim 1 , wherein said composition comprises at least 40 wt. % HA but less than 10 wt. % HA.  
   
   
       13 . The composition of  claim 12 , wherein said composition comprises at least 45 wt. % HA.  
   
   
       14 . The composition of  claim 12 , wherein said composition comprises at least 50 wt. % HA.  
   
   
       15 . The composition of  claim 12 , wherein said composition comprises at least 60 wt. % HA.  
   
   
       16 . The composition of  claim 12 , wherein said composition comprises at least 65 wt. % HA.  
   
   
       17 . The composition of  claim 12 , wherein said composition comprises at least 70 wt. % HA.  
   
   
       18 . The composite of any of  claims 1  to  17  wherein said composite has a bending strength of from about 33.9 to about 41.4 MPa.  
   
   
       19 . The composite of any of  claims 1  to  17  wherein said composite has a compression strength of from about 32 to about 75 MPa.  
   
   
       20 . The composite of any of  claims 1  to  17  wherein said composite has a tensile strength of from about 6 to about 10 MPa.  
   
   
       21 . The composite of any of  claims 1  to  17  wherein said composite has a shear strength of from about 23 to about 28 MPa.  
   
   
       22 . The composite of any of  claims 1  to  17  wherein said composite has a bending modulus of from about 0.275 to about 0.502 GPa.  
   
   
       23 . The composite of any of  claims 1  to  17  wherein said composite has a compression modulus of from about 0.19 to about 0.45 GPa.  
   
   
       24 . The composite of any of  claims 1  to  17  wherein said composite has a compression modulus of from about 0.02 to about 0.34 GPa.  
   
   
       25 . The composition of  claim 1 , wherein said composition further comprises a polymer is selected from the group consisting of poly(hydroxyvalerate), poly(lactide-co-glycolide), poly(hydroxybutyrate), poly(hydroxybutyrate-co-valerate), polyorthoester, polyanhydride, poly(glycolic acid), poly(glycolide), poly(L-lactic acid), poly(L-lactide), poly(D,L-lactic acid), poly(D,L-lactide), poly(caprolactone), poly(trimethylene carbonate), and polyester amide.  
   
   
       26 . The composition of  claim 1 , wherein said composition is molded into an orthopedic fixation device.  
   
   
       27 . The composition of  claim 26 , wherein said orthopedic fixation device is selected from the group consisting of a bone screw, a bone pin, a bone rod, and a bone plate.  
   
   
       28 . An artificial bone, wherein said bone is comprised of a composition of any of claims  1 - 17 .  
   
   
       29 . A substrate for use in an implantable device comprising a composition of any of claims  1 - 17 , formulated into an orthopedic fixation device or an artificial bone structure.  
   
   
       30 . The substrate of  claim 29 , wherein said substrate further comprises a surface modification to facilitate implantation of said device with a decreased risk of implant rejection.  
   
   
       31 . A method of producing an implantable device, comprising: 
 a. preparing a composition according to any of claims  1 - 17 ; and    b. molding the composition of (a) into an orthopedic fixation device or an artificial bone for implantation.    
   
   
       32 . The method of  claim 31 , wherein said fixation device is selected from the group consisting of a bone screw, a bone pin, and a bone plate.  
   
   
       33 . An implantable device comprising a polymer composition of any of claims  1 - 17 .  
   
   
       34 . A composition comprising a composite of: 
 a) a citric acid polyester having the generic formula (A-B-C) n , wherein A is a linear aliphatic dihydroxy monomer; 
 B is citric acid,  
 C is a linear aliphatic dihyroxy monomer, and  
 n is an integer greater than 1; and  
   b) a bioceramic used for implantable tissue devices, wherein at least 30 wt. % weight ratio of said composition comprises said bioceramic.

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