WO2006010507A2

WO2006010507A2 - Bioresorbable material for filling bone defects

Info

Publication number: WO2006010507A2
Application number: PCT/EP2005/007768
Authority: WO
Inventors: Arne Briest; Ingo Mücke
Original assignee: Ossacur Ag
Priority date: 2004-07-22
Filing date: 2005-07-16
Publication date: 2006-02-02
Also published as: WO2006010507A3; DE102004036882A1

Abstract

Disclosed is the use of a demineralized xenogenic bone material as a bioresorbable material for filling bone defects. Preferably, said bone material can be additionally degreased and/or be extracted with guanidine. The inventive material can be provided in the form of powder, granulate, or a molded element.

Description

description

Bioresorbable material for filling bone defects

The present invention relates to a bioresorbable material for filling bone defects.

Bone defects are to be treated in many areas of medical care, especially in orthopedics, accident surgery, maxillofacial surgery and hand surgery. Bone defects occur, for example, in fractures, in particular in debris fractures, in the clearance of cysts and tumors, in osteoporosis, in the use of hip joint prostheses, in degenerative diseases of the spine and in tooth extractions, root tip resections, partial epidural reconstructions and peridontal defects. Often it makes sense to fill up bone defects in order to replace the original Knochen¬ material or to stimulate the regeneration of new bone and bone. To fill bone defects, a large number of different materials are already being used. For example, fully synthetic bone substitutes based on calcium phosphate or transplants of natural bone or bone fragments are used. It is particularly advantageous if the material which is used to replenish the Knochendefekte- _^, allows the reconstruction autologous bone, so that the external material can be more or less completely replaced by körperei¬ antigenic material support after some time. Therefore, the ability of the filler to be absorbed by the body plays a major role. Previously used bones, bone splits or inorganic Knochener¬ set materials have the disadvantage that the absorption takes a very long time. In addition to the surface structure and porosity of the Füllma¬ terials, which plays an essential role in the absorption, the absorption of the inorganic portion of the filler is the speed-determining step.

The invention therefore has as its object to provide a material for filling bone defects, which essentially corresponds to the natural bone composition, but nevertheless is degradable well and at relatively high speed. This material should have osteoconductive properties, ie provide a support structure for the reconstruction of endogenous bones. In addition, it should also be possible to provide this filling material with osteoinductive properties, ie with properties which promote and support the formation of endogenous bone or cartilage tissue in a particular manner or with properties which are otherwise advantageous.

This object is achieved by a use as described in claim 1. Preferred embodiments of this use are set forth in the dependent claims. By reference - -

the wording of all claims is made part of the description.

According to the invention, a demineralized xenogenic bone material is used as bioresorbable material for filling bone defects. Such a demineralized bone material is a so-called bone matrix, from which the inorganic portion (minerals) is almost completely removed except for traces. One therefore speaks of demineralized bone matrix, abbreviated DBM. The bone material used according to the invention therefore essentially consists only of the organic matrix, which, however, largely corresponds to the natural composition of the bone.

In general, about 70% of a natural bone consists of inorganic components, mainly hydroxyapatite. In addition to about 10% of water, the remaining 20% of organic constituents are formed, these being mainly collagen. To a small extent, non-collagenous proteins, in particular osteocalcin, osteonectin and osteopontin, cytokines, growth factors, proteoglycans and fats are present. The demineralized bone material used according to the invention therefore essentially represents a mixture of various proteins (proteins) whose main component is collagen. Advantageously, these are mainly collagen type I. Conventionally already used collagen sponges are generally prepared from skin or tendons. They also consist at least partly of collagen type I, which may be present in the native state. In these products, however, the "natural environment" is destroyed In contrast to this, the proteins of the demineralized bone material used according to the invention are in the natural state, environment and composition of the proteins of the bone material used according to the invention - A -

are not artificially brought into a new shape. The natural network of collagen fibers and / or fibrils is therefore still preserved. This has the effect that the demineralized bone material used in accordance with the invention comes very close in its composition and structure to natural bone and thus to ideal osteoconductive proteins owns properties. This material is therefore particularly advantageous for the filling of bone defects. In addition, the demineralized bone material used according to the invention as an organic matrix in the body is rapidly degraded and thus enables and promotes the formation of endogenous bone material in a special way.

The demineralized bone material used according to the invention is xenogenic material, ie bone material of a foreign origin. When filling bone defects in humans, therefore, no human bone (allogeneic material) is used as starting material for the production of the bioabsorbable material. This has the advantage that the risk of transmissible (pathogenic) pathogens is significantly reduced. Bone material xenogeneic origin generally has no or only a few pathogens that could be dangerous for humans. Xenogenic material is therefore less risky than allogeneic material, since human pathogens are relatively rare in xenogeneic material. Nevertheless, it is advantageous to carry out an inactivation of possible pathogens, since it can not be ruled out in general that previously unknown pathogens can occur in the material or known pathogens jump over the species boundaries. However, by the use of xenogenic originating material, inactivation of various possible pathogenic pathogens can be reduced to a minimum. In general, degreasing and demineralizing the material to activate transmissible pathogens is sufficient. Besides the advantage of simplifying the manufacturing process, this has continued - -

the advantage that material-inherent positive properties of the demineralized bone material used according to the invention are not impaired by additional treatments.

In a particularly preferred embodiment of the use according to the invention, the bone material used is degreased. Here, the fat content of the natural bone composition can be reduced or almost completely removed. Such degreasing can be carried out before or after the demineralization of the bone material. The processes of demineralization and degassing effectively also inactivate the transmissible pathogens possibly contained in the xenogenic source material.

In a particularly preferred embodiment of the use according to the invention, the material can be produced by grinding bone, demineralizing in particular with acid, extracting with guanidine and further working up of the insoluble fraction of the demineralized material to establish a tissue-compatible environment. Furthermore, the material can be degreased at any time prior to further processing to adjust the tissue-compatible environment with preferably organic solvent. Advantageously, this degreasing step takes place before or after demineralization with acid. Milling of the bone to bone meal is carried out according to methods familiar to the person skilled in the art. It is particularly advantageous that the resulting bone meal has a particle size range of about 30 to about 3,000 μm, preferably about 100 to about 2,000 μm. In order to set a suitable particle size, the bone can be ground and / or sieved accordingly. The degreasing is preferably carried out with the aid of ethanol and / or acetone. Hydrochloric acid is preferably used for demineralization (decalcification). Before further working up of the material, extraction with guanidine, in particular with guanidinium hydrochloride, is carried out. The extraction with guanidine dissolves part of the otherwise insoluble bone matrix, primarily a part of the collagen and low molecular weight proteins. In this case, the insoluble fraction is worked up further in accordance with the above description. This extraction reduces the osteoinductivity of the resulting material, which may be advantageous depending on the desired application. In this case, materials are thereby produced whose osteoconductive properties are in the foreground. These materials can be specifically modified by the addition of further substances in their properties. The extraction step can advantageously be used to remove or inactivate possibly present transmissible pathogens.

The further work-up of the material is advantageous in order to be able to provide a tissue-friendly product which is well worn by the patient. In this so-called conditioning process chemicals are mainly removed. This can advantageously be carried out in such a way that the resulting particles are washed free of chemicals and neutral with water, saline water and / or buffer. The resulting moist material can be adjusted in dry matter content. It can be moist or dry.

In principle, all animals with skeletal system come into question as source for the xenogenic bone material. Cow, horse or pig, ie bovine, equine or porcine starting material, are particularly preferred. In principle, all types of bones of the skeleton can be used, in particular long bones, above all the cortex of the long bones.

In a preferred embodiment of the Verwen¬ tion according to the invention, the bioresorbable material is used as a powder for the application in front. Powder here is to be understood as meaning a material in which the bone meal particles are essentially present next to one another. Particular preference is given to powders having a particle size of between about 30 and about 3,000 μm, in particular between about 100 and about 2,000 μm. The particle size can be adjusted either by suitable implementation of the bone milling process and / or by sieving the resulting particles.

In a further preferred embodiment of the use according to the invention, the bioresorbable material is present as granules for the application. For the purposes of the invention, a granulate consists of granules lat grains. Such a granular grain is produced by storing several bone meal particles together to form a superordinate structure. These may, for example, be spherical shapes. A granular comet is therefore in principle a small shaped body which can be round or rounded. Granules can be produced, for example, by thermal and / or pressing pressure treatment from bone meal, ie from a powder. In this case, a pressure is to be understood by pressing pressure, which pressure is built up within a press. The particle size of the bone meal or the powder or granules can be adjusted to a defined size range. The particle size distribution can be chosen differently for different applications.

In a further particularly preferred embodiment of the use according to the invention, the material is present as a shaped body. Under moldings are aggregates of bone meal particles with definier¬ ter shape, for example, blocks, cuboids, slices or the like to understand. It can create moldings of any shape. The moldings can be adapted to the defects to be filled out by mechanical processing by the user. "Granules and shaped bodies essentially differ only in size. A shaped body can also be produced by thermal and / or pressing pressure treatment of powder or granules.

The use of the bioresorbable material as a powder, as a granule or as a shaped article depends essentially on the particular application, the method of treatment and the stability to be required. Powders or granules are especially suitable for the filling of small bone defects. For larger defects, it may be advantageous to use a shaped body, which is optionally adapted accordingly by the user.

A particular advantage of the use according to the invention of the bioabsorbable material lies in its porosity. By the expression of the porosity, the vulnerability is influenced by the body's own factors, in particular by cells. In this way, the degradability in the body is influenced. Advantageously, a majority of the pores of the material is in the size range over 100 microns. These pores are thus optimally suitable for ingrowth of cells. This promotes the integration of the filling material in the body as well as its degradation or absorption. Interconnecting, ie substantially continuous, pores are particularly advantageous. The pores in the materials are essentially generated by the particle size distribution of the bone meal. They differ in the bed, so in powder or granules, and in such moldings, which are produced with minimal pressure, only insignificantly. In addition, the porosity of the granules is also determined by the treatment conditions for the preparation of the granules, especially temperature and time. In addition to the pores that are present in the granules themselves, in a bulk granule, there are also interspaces between the individual granules, which can be varied by the shape of the granules. The porosity of moldings is on the one hand by the grain size of the starting material and on the other by the pressing pressure and the - -

other manufacturing conditions of the shaped body, especially tempera ture and time determined. By setting the various conditions which exert an influence on the porosity and in particular on the pore size, the porosity can be defined and adapted to the respective conditions of use. As already mentioned, pore sizes of about 100 μm and larger are particularly advantageous.

The stability especially of the granules and moldings can also be influenced by the production conditions. Important factors here are the particle size of the starting material, the pressure in particular in the production of moldings and the other conditions of manufacture, especially temperature and time.

In a further preferred embodiment of the use according to the invention of the bioresorbable material, the material is dried or is in dry form, in particular if it is present as a shaped body. In the case of powder and granules, both a dry and a moist form of delivery may be preferred. With particular advantage, the material ultimately used is dried or is in dry form. The presence in dry form is particularly advantageous in terms of stability and durability, since the product moisture generally adversely affects the stability and durability. During the manufacture of the material, e.g. When pressing a Form¬ body, the material is preferably present as a wet mass. Hier¬ by an agglomeration and thus a substantially stable intermediate form is achieved, which can be further stabilized by further treatment.

Drying can be carried out, for example, by lyophilization and / or by air drying. The drying can be supported by Temperatur¬ application and / or vacuum. The drying can - -

take place in wide temperature ranges. It should be borne in mind that the type and conditions of drying can influence the properties of the bioresorbable material. For example, in a gentle form of drying, a demineralized and defatted bone material is made at low temperatures under vacuum. By appropriate spreading of particles before and / or slight mechanical forces after drying, a free-flowing powder can be produced. With the aid of a suitable device, for example a granulating plate, with subsequent drying, a granule having different particle sizes can be prepared. By pressing before drying, any shaped body can be produced.

In the case of drying the bioresorbable material, it is often advantageous to employ suitable reconstitution agents so that rewetting of the material does not adversely affect the properties of the material.

The properties of a lyophilized material often differ from the properties of a temperature treated material. For example, a shaped body produced from lyophilized material has a relatively low stability, so that the addition of binders for the production of the shaped body can be advantageous.

In a further preferred embodiment of the use according to the invention, the material is sterilized or is present in sterilized form. For sterilization conventional methods come into question. For example, the bioresorbable material can be irradiated, in particular with radioactive rays, and / or gassed, in particular with ethylene oxide. If the bioresorbable material is provided with additives, active substances and / or extracts (see below), it must generally be taken into account that the sterilization measures the effectiveness of the substances used Can affect substances. For example, when using the antibiotic gentamycin in the bioresorbable material, it is advantageous to sterilize by gassing with ethylene oxide. Furthermore, aseptic preparation of the bioresorbable material is advantageous, as this can prevent problems during sterilization.

Furthermore, it is preferred if the bioresorbable material is present in packaged form. It is particularly preferred if the material is packed sterile. Within such a package, the material can be shipped and / or stored. During the actual application, the material can be removed from the packaging in a simple manner and used. In order to achieve sterility, it may be provided, for example, that the body is sterilized before packaging or even inside the packaging, for example by irradiation. Suitable materials for packaging are various materials, for example plastic casings or the like. As packaging u. a. also special syringes, in which the piston does not end or only in a slight rejuvenation. In such syringes, for example, the moist bioresorbable material, which can be adjusted to a defined dry matter content, are filled and thus provided for the user in a practical manner. In order to adjust the moist material to an optimum application consistency, additives and / or active ingredients can be added to the syringes before the actual filling.

In a further particularly preferred embodiment of the use according to the invention, the material is provided with at least one additive, active substance and / or extract. Due to its structure, the bioresorbable material used according to the invention is particularly advantageously suitable as a carrier for such additives, active substances, extracts or, for example, also for cells which likewise to be understood hereunder. In general, the properties of the material used according to the invention can be defined and adjusted by such substances in order to adapt the material according to the invention to the respective applications. As additives, agents or extracts are a variety of substances in question. However, biologically active additives and / or active substances or biological extracts are particularly preferred. Such substances may be advantageous for product protection by z. B. prevent microbial degradation. Furthermore, substances can be used which are advantageous for therapeutic reasons (drug delivery system) and / or in promoting bone healing and bone regeneration. Furthermore, physical properties of the bioresorbable material used according to the invention can also be specifically modulated by additives. The release of active ingredients from the material can be influenced by other additives.

Suitable active substances, in particular as biologically active substances, are in particular those substances which are locally effective and effect their effect in the immediate vicinity of the bone defect. On the other hand, systemically active substances can also be introduced into the body through the bioresorbable material. This depends on the particular application and the defect to be treated.

A binder and / or a crosslinking agent can advantageously be used as additive or as active substance, whereby the modifi cation possibilities of the bioresorbable material are increased in a wide range. As a result, for example, the stability and / or the porosity of the material can be influenced. Especially the addition of binders influences the porosity. For example, when particles are merely agitated with the binder, porosity tends to be greatly reduced. If this is not desired, depending on the application, a superficial conditioning of the individual - -

advantageous, d. H. So a superficial treatment of the individual particles with binder. By adding amphoteric agents and / or salts, the hydrophilicity of the bioresorbable material can be influenced. Biological substances are particularly preferred as amphoteric agents. Furthermore, a reconstitution agent can be provided as additive. This is particularly advantageous if the bioresorbable material is in dried form and is remoistened before use. The rewetting of dried biopolymers can be problematic since the biopolymers or the bioresorbable material may no longer have the desired properties after rewetting. In this case, it is advantageous if, prior to drying, substances are added which are advantageous in the reconstitution and which, after addition of, for example, water or physiological saline solution, produce the desired consistency and the desired properties of the bioresorbable material. Furthermore, substances which generally influence the consistency of the bioresorbable material can be used as additives. For this purpose, primarily substances come into question with which the viscosity can be set in a defined manner. For example, salts are suitable, in particular salts of anionic or cationic polymers and / or biopolymers.

As an additive or as an active ingredient, in particular as a biologically active ingredient, growth factors, cytostatics, antibiotics, radioactive materials and / or antibodies are preferred. By means of such substances, for example, the bioresorbable material itself can be protected, in particular against bacterial decomposition. In addition or as an alternative to this, the bioresorbable material can hereby be provided with specific functions which unfold advantageous action in the body of the patient. This can be done, for example, for therapeutic reasons and / or to support the nodules. healing and / or regeneration. As a result, the material can be provided with osteoinductive properties.

By using growth factors or osteoinductive factors, in particular, the bone and / or cartilage renewal can be induced or promoted, which speeds up the integration and healing processes in the patient. Suitable growth factors are, for example, BMP {bovine morphogenetic protein), in particular BMP-2, BMP-7 and / or BMP-4, and IGF (insuline-like growth factor, in particular IGF-I, and TGF (transforming growth factor) In addition, the bioresorbable material may be provided with one or more cytostatics, which is particularly advantageous in the case of cancerous changes in the region of the bone defect and / or the surrounding tissue Furthermore, the use of antibiotics as the active ingredient is preferred, which on the one hand can avoid defense reactions in the body, and on the other hand can also protect the bioabsorbable material from product damage In addition, the use of antibodies in this context may be useful, in particular a for therapeutic reasons. These various exemplified substances and other active substances can be combined with each other and thus achieve particularly advantageous effects. Which additives and / or active ingredients are chosen, of course, depends on the particular application.

Advantageously, the bioresorbable material may be provided with an extract, in particular a biological extract. Such an extract may contain, for example, a combination of various active substances which may be biologically active. Such an extract is preferably obtained from biological material. For example, can it is an extract of demineralized bone material containing various, especially biologically active, substances which are very active with regard to bone or cartilage formation. With regard to the components and the preparation of such an exemplary extract, reference is made to the disclosures of international patent applications WO 91/06324 and WO 93/20857. Such an extract is sold as a product by the applicant under the trade name "COLLOSS." Preferably, such an extract can be used in combination with other active substances, in particular with other biologically active substances.

The additives, active ingredients and / or extracts can be mixed with the bioabsorbable material, which is present for example from powder, and thus made available for use. On the other hand, it is also possible to apply these substances in the form of a coating on the bioresorbable material. This is particularly advantageous in the case of granules and above all in the case of moldings. For example, demineralized and in particular also defatted and / or further extracted bone material can advantageously be coated with an extract, in particular with the mentioned "COLLOSS." Shaped articles are particularly suitable for such a coating means for the use of "COLLOSS" according to the cited patent applications that the final stage resulting from the production of the extract is used prior to lyophilization. A coating of this kind can be used to produce a bioabsorbable material that is both osteoconductive and osteoinductive. It has an advantageous stability and has rapid resorbability, since no slowly resorbable inorganic material is present. The pore structure is optimized not only between the individual particles but also within the particles, thereby providing an interconnecting porosity which is also accessible to cells within the particles. Due to the coating tion of the material, the extract with its active substances in the bone defect to be filled is distributed in an optimal manner. In particular, collapse of the material used is prevented by the stability of the particles. Furthermore, the substances contained in the extract are advantageously presented on the inner and / or outer surface of the particles, so that these substances are available to the body, in particular to the body's own cells. This accessibility of the active substances is markedly improved, for example, in comparison with autologous bone as filling material.

The addition of the substances can take place before or after drying the material. In this case, either the ready-to-bioresorbable material with the additives for the application can be provided, or the user is given the opportunity to coat the material himself or to coat the other substances. This can be done by offering a kit containing all the essential components. In the production of end products which already contain additives, active substances and / or extracts, their stability should be taken into account with respect to the production conditions and the sterilization process. In the event that the user provides the product itself with appropriate substances, this advantageously must not be taken into account.

By providing them with additives, active ingredients and / or extracts, on the one hand outer surfaces of the bioresorbable material and on the other hand additionally or alternatively cavities or inner spaces of the bioresorbable material may be provided with the substances. It is particularly preferred if active substances are used in such a way that a controlled release is made possible. This can be done, for example, by the fact that interiors and / or pores of the bioresorbable material with the effective Sub- punched or modified so that the drug gebun¬ the and then released retarded.

The material used according to the invention can be provided as a kit for the application. This kit comprises at least one demineralized xenogenic bone material and preferably at least one additive, active substance and / or an extract. With the aid of such a kit, the user has the possibility of providing the demineralized xenogenic bone material which is used to fill bone defects with one or more active substances which may be adapted to the respective application. Therefore, various substances can be provided as additives, active ingredients and / or extracts in the kit, so that the user can select the respective suitable substance or substances. In addition, the separate provision of demineralized xenogenic bone material and the other substances can enable increased storage stability. For further features of the kit according to the invention or the demineralized xenogenic bone material and the additives, active ingredients and / or extracts, reference is made to the above description. In addition to the already described components, the kit may, for example, also contain components which are suitable for rewetting or reconstitution of the material present in this case in dry form. These are, for example, sterile water, physiological saline or suitable buffers. Furthermore, in such a kit, other aids, such as tools, may be included, which can be used in the course of the application to the patient.

Further features of the invention will become apparent from the following description of examples in combination with the subclaims. - -

In this case, the various features can be implemented individually or in combination with each other.

Examples

1. Preparation of a powder

Moist demineralized, degreased and extracted with Gyanidiniumhydrochlorid bone matrix having a particle size of <2,000 microns is spread over a large area in a bowl and dried at temperatures up to 200 ⁰ C, especially at 40 to 120 ⁰ C, for 2 to 40 hours. Subsequently, adhering particles are mechanically destroyed. The powder can be fractionated and filled on a sieve into different particle sizes. After packaging into a suitable packaging, a sterile product is obtained after sterilization by conventional methods, in particular by irradiation.

2. Production of a shaped body

For the production of a shaped body having a diameter of 0.8 mm and a height of 0.5 mm, about 1.3 g (based on dry substance) of a demineralized, degreased and extracted with guanidinium hydrochloride bone matrix with a particle size underside half of 2,000 microns used. The wet matrix is placed in a press consisting of a 0.8 cm diameter tube and a flask. By compressing a moist shaped body of about 0.5 cm height is generated. This is followed by a Temperaturbe¬ treatment at up to 200 ° C, in particular at 40 to 120 ° C, for 2 to 40 hours. As a result, a dry, porous, mechanically stable shaped body with dimensions of 0.5 mm (height) x 0.8 mm (diameter) won. After packing in a suitable packaging is - -

after sterilization by conventional methods, in particular with irradiation, a sterile product obtained.

Claims

claims

1. Use of a demineralized xenogenic bone material as bioresorbable material for filling bone defects.

2. Use according to claim 1, characterized in that the bone material is degreased.

3. Use according to claim 1 or claim 2, characterized gekenn¬ characterized in that the bone material can be produced by

Milling of bones, optionally degreasing with organic solvent, preferably with ethanol and / or acetone, demineralizing with acid, preferably with hydrochloric acid, extracting with guanidine, in particular with guanidinium hydrochloride, and further workup of the insoluble fraction to adjust a tissue-compatible milieus.

4. Use according to one of the preceding claims, characterized in that the xenogenic bone material originates from bovine, equine and / or porcine starting material.

5. Use according to one of the preceding claims, characterized in that the material is present as a powder, in particular as a powder having a particle size between about 30 and about 3,000 microns, preferably between about 100 and about 2,000 microns.

6. Use according to one of claims 1 to 4, characterized gekenn¬ characterized in that the material is present as granules.

7. Use according to one of claims 1 to 4, characterized gekenn¬ characterized in that the material is present as a shaped body.

8. Use according to one of the preceding claims, characterized in that the material is dried.

9. Use according to one of the preceding claims, characterized in that the material is sterilized and / or prepared aseptically.

10. Use according to one of the preceding claims, characterized in that the material with at least one Zusatz¬ substance and / or active ingredient, in particular a biologically active Zu¬ added material and / or active ingredient, and / or an extract, in particular a biological extract provided is.

11. Use according to claim 10, characterized in that the additive and / or active ingredient is a binder, a Vernetzungsmit¬ tel, an amphoteric agent, a salt, a reconstitution agent, a growth factor, a cytostatic, an antibiotic, a radioakti¬ ves material and / or an antibody.