US4610692A — Implant for filling bone cavities and fixing bone…

Claim 1

Independent Claim 138 words

Method of producing sintered tricalcium phosphate implants for filling bone cavities and for fixing bone fragments in a living body, which comprises mixing tricalcium phosphate with at least one substance which under heat sufficiently high to bake said tricalcium phosphate, forms a gas, shaping the thus-formed mixture into shaped bodies thereof, baking the shaped bodies at a temperature sufficiently high to cause gas formation from said substance, thereby forming pores in said shaped bodies, impregnating said shaped porous bodies with a therapeutically-active ingredient, thereby distributing the same in the pores, and coating at least a portion of one of said shaped, porous bodies having said therapeutically-active ingredient distributed therein, with a coating of a predetermined thickness of a biodegradable substance, whereby the time of absorption of said therapeutically-active ingredient is controlled by the thickness of said biodegradable substance.

Claim 2

Dependent Claim 138 words

Method of producing sintered tricalcium phosphate implants for filling bone cavities and for fixing bone fragments in a living body, which comprises mixing tricalcium phosphate with at least one substance which under heat sufficiently high to bake said tricalcium phosphate, forms a gas, shaping the thus-formed mixture into shaped bodies thereof, baking the shaped bodies at a temperature sufficiently high to cause gas formation from said substance, thereby forming pores in said shaped bodies, impregnating said shaped porous bodies with a therapeutically-active ingredient, thereby distributing the same in the pores, and coating at least a portion of one of said shaped, porous bodies having said therapeutically-active ingredient distributed therein, with a coating of a predetermined thickness of a biodegradable substance, whereby the time of absorption of said therapeutically-active ingredient is controlled by the thickness of said biodegradable substance.

Claim 3

Dependent Claim 31 words

The method of claim 1 in which said gas-forming substance is selected from a group consisting of hydrogen peroxide, urea, sugar, ammonium bicarbonate, ammonium carbamate, calcium hydrogen phosphate, and mixtures thereof.

Claim 4

Dependent Claim 28 words

The method of claim 2 in which about 1% to about 3% by weight of hydrogen peroxide, based on the weight of said tricalcium phosphate, is mixed therewith.

Claim 5

Dependent Claim 27 words

The method of claim 2 in which about 10% to about 20% by weight of urea, based on the weight of said tricalcium phosphate, is mixed therewith.

Claim 6

Dependent Claim 29 words

The method of claim 1 in which about 3% to about 30% by weight of said gas-forming substance, based on the weight of said tricalcium phosphate, is mixed therewith.

Claim 7

Dependent Claim 29 words

The method of claim 5 in which about 10% to about 20% by weight of said gas-forming substance, based on the weight of said tricalcium phosphate, is mixed therewith.

Claim 8

Dependent Claim 33 words

The method of claim 1 in which said shaped, porous bodies are impregnated with up to about 45% by weight of said therapeutically-active ingredient, based upon the weight of said baked, porous bodies.

Claim 9

Dependent Claim 35 words

The method of claim 7 in which said therapeutically-active ingredient is selected from the group consisting of polyvinyl pyrrolidone iodine, penicillin, cycloserin, bacitracin, nystatin, amphotericin, gentamycin, novobiocin, erythromycin, momycin, streptomycin, flucloxacillin, sulfonamide and mixtures thereof.

Claim 10

Dependent Claim 14 words

The method of claim 7 in which said therapeutically-active ingredient is polyvinyl pyrrolidone iodine.

Claim 11

Dependent Claim 28 words

The method of claim 9 in which said shaped, porous bodies are impregnated with a solution or complex of polyvinyl pyrrolidone iodine having about a 10% iodine content.

Claim 12

Dependent Claim 21 words

The method of claim 1 in which said biodegradable substance is selected from at least one of polymethacrylate, polylactide, and polydextran.

Claim 13

Dependent Claim 36 words

The method of claim 1 comprising the additional step of mixing at least one fluoride compound selected from at least one of alkaline metal fluorides and alkali earth fluorides, with said tricalcium phosphate prior to baking.

Claim 14

Dependent Claim 27 words

The method of claim 12 in which said fluoride compound is selected from the group consisting of CaF 2 , NaF, MgF 2 , and mixtures thereof.

Claim 15

Dependent Claim 35 words

The method of claim 1 in which the thus-formed mixture is formed into a plurality of bodies each having its own discrete shape and dimensions, which are subsequently baked to form said discretely-shaped, porous bodies.

Claim 16

Dependent Claim 28 words

The method of claim 1 wherein said biodegradable substance is coated to have a predetermined thickness from about 4 microns to about 30 microns on said porous bodies.

Claim 17

Dependent Claim 28 words

The method of claim 15 wherein said bidegradable substance is coated to have a predetermined thickness of about 8 microns to about 20 microns on said porous bodies.

Claim 18

Dependent Claim 87 words

A sintered tricalcium phosphate implant for filling bone cavities and for fixing bone fragments in a living body, comprising a discretely-shaped, baked porous body of tricalcium phosphate, at least one therapeutically-active ingredient impregnated into said porous body and distributed among the pores therein, and at least one coating of predetermined thickness of a biodegradable substance on at least a portion of said porous body impregnated with said therapeutically-active ingredient, whereby the time of absorption of said therapeutically-active ingredient is controlled by the thickness of said biodegradable substance.

Claim 19

Dependent Claim 87 words

A sintered tricalcium phosphate implant for filling bone cavities and for fixing bone fragments in a living body, comprising a discretely-shaped, baked porous body of tricalcium phosphate, at least one therapeutically-active ingredient impregnated into said porous body and distributed among the pores therein, and at least one coating of predetermined thickness of a biodegradable substance on at least a portion of said porous body impregnated with said therapeutically-active ingredient, whereby the time of absorption of said therapeutically-active ingredient is controlled by the thickness of said biodegradable substance.

Claim 20

Dependent Claim 63 words

The implant of claim 17 wherein said discretely-shaped porous body of tricalcium phosphate, is formed by mixing the same with at least one substance which under heat sufficiently high to bake said tricalcium phosphate, forms a gas; and baking said shaped body at a temperature sufficiently high to cause gas formation from said substance, thereby forming a discretely-shaped, porous body of tricalcium phosphate.

Claim 21

Dependent Claim 30 words

The implant of claim 18, wherein said gas-forming substance is selected from the group consisting of hydrogen peroxide, urea, sugar, ammonium bicarbonate, ammonium carbamate, calcium hydrogen phosphate, and mixtures thereof.

Claim 22

Dependent Claim 27 words

The implant of claim 19 wherein about 1% to about 3% by weight of hydrogen peroxide, based on the weight of said tricalcium phosphate, is mixed therewith.

Claim 23

Dependent Claim 26 words

The implant of claim 19 wherein about 10% to about 20% by weight of urea, based on the weight of said tricalcium phosphate, is mixed therewith.

Claim 24

Dependent Claim 35 words

The implant of claim 17, in which said therapeutically-active ingredient is selected from the group consisting of polyvinyl pyrrolidone iodine, penicillin, cycloserin, bacitracin, nystatin, amphotericin, gentamycin, novobiocin, erythromycin, momycin, streptomycin, flucloxacillin, sulfonamide and mixtures thereof.

Claim 25

Dependent Claim 21 words

The implant of claim 17, in which said biodegradable substance is selected from at least one of polymethacrylate, polylactide, and polydextran.

Claim 26

Dependent Claim 33 words

The implant of claim 22, in which said shape, porous body is impregnated with up to about 45% by weight of said therapeutically-active ingredient, based upon the weight of said baked, porous body.

Claim 27

Dependent Claim 13 words

The implant of claim 24, wherein said therapeutically-active ingredient is polyvinyl pyrrolidone iodine.

Claim 28

Dependent Claim 34 words

The implant of claim 17, in which said discretely-shaped, porous body of tricalcium phosphate additonally comprises at least one fluoride compound selected from at least one of alkali metal fluorides and alkaline earth fluorides.

Claim 29

Dependent Claim 27 words

The implant of claim 26, in which said fluoride compound is selected from the group consisting of CaF 2 , NaF, MgF 2 , and mixtures thereof.

Claim 30

Dependent Claim 21 words

The implant of claim 17 wherein the thickness of said biodegradable substance is from about 4 microns to about 30 microns.

Claim 31

Dependent Claim 21 words

The implant of claim 28 wherein the thickness of said biodegradable substance is from about 8 microns to about 20 microns.

Claim 32

Dependent Claim 26 words

A sintered tricalcium phosphate implant for filling bone cavities and for fixing bone fragments in a living body, prepared by the method according to claim 1.

Claim 33

Dependent Claim 87 words

An implant system for filling bone cavities and for fixing bone fragments in a living body, said system comprising discretely-shaped, porous bodies of tricalcium phosphate, at least one therapeutically-active ingredient impregnated into said porous bodies and distributed among the pores therein, and at least one coating of predetermined thickness of a biodegradable substance on at least a portion of one of said porous bodies impregnated with said therapeutically-active ingredient, whereby the time of absorption of said therapeutically-active ingredient is controlled by the thickness of said biodegradable substance.

Claim 34

Dependent Claim 87 words

An implant system for filling bone cavities and for fixing bone fragments in a living body, said system comprising discretely-shaped, porous bodies of tricalcium phosphate, at least one therapeutically-active ingredient impregnated into said porous bodies and distributed among the pores therein, and at least one coating of predetermined thickness of a biodegradable substance on at least a portion of one of said porous bodies impregnated with said therapeutically-active ingredient, whereby the time of absorption of said therapeutically-active ingredient is controlled by the thickness of said biodegradable substance.

Claim 35

Dependent Claim 51 words

The system of claim 31 wherein at least one porous body is coated with said biodegradable substance having a thickness of about 8 microns, at least one other porous body is coated with biodegradable substance having a thickness of about 20 microns, and at least a third porous body remains uncoated.

Claim 36

Dependent Claim 23 words

A method for filling bone cavities and for fixing bone fragments after fractures, which comprises employing an implant system according to claim 31.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1989-09-08	1990-03-10	1990-09-09	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1993-09-08	1994-03-10	1994-09-09	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1997-09-08	1998-03-10	1998-09-09	$7700.00	Window Closed / Lapsed

Implant for filling bone cavities and fixing bone fragments in a living body, method of producing the same, and bone implant system

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag