FR2852249A1 - Bone filling material, especially for use in oral implants, comprises source of phosphate and calcium and stimulant of collagen production by osteoblasts e.g. hydroxyproline mono- or di-palmitate - Google Patents

Abstract

Bone filling material (I) comprises: (A) at least one source of phosphate and calcium, and (B) at least one compound for stimulating local production of collagen by osteoblasts.

Description

The present invention relates to a new biomaterial usable in

  particular as a bone filling material. It is particularly suitable for bone filling in the field of oral implantology in paradontology and odontology.

  Bone is a complex mineralized system, comprising an organic phase (the organic or osteoid matrix), a mineral phase and water. The mineral phase consists mainly of crystalline calcium phosphate (hydroxyapatite), while the organic phase consists of collagen type 1, the main compound, and non-collagenic proteins.

  The formation of bone, as well as its renewal and resorption, are linked to the action of specific cells, osteoblasts, osteocytes and osteoclasts. Osteoblasts produce the extracellular matrix, or osteoid matrix, formed of type II collagen. , then transformed into type I collagen. The growth of calcium phosphate crystals and the organization of coilagen lead to mineralization or calcification of bone tissue.

  For a few years now, it has been known to prepare synthetic materials based on calcium phosphates, intended to form synthetic bone, which in particular makes it possible to avoid resorting to autogenic or heterogeneous bone grafts. These bone filling materials can be used in different circumstances, such as the treatment of fractures, the fixing of metallic prostheses or screws, and in the dental field as well as in plastic surgery.

  The main component of these materials is a source of calcium, such as dicalcium (DCP), tricalcium (alpha and beta TCP), and tetracalcium (TTCP) phosphates, which, in the presence of water, give hydroxyapatite. This hydroxyapatite formed in situ in an aqueous environment substantially resembles natural hydroxyapatite, allows bone reconstruction by integrating easily into the bone structures in formation. Examples are described in the following documents: US-A6,206,957, US-A-6,323,146, US-A-6,325,992, US-A4,518,430 (Re.33,221), USA-4,612,053, US-A-4,880,610, US- A-5,053,212, US-A5,152,836, US-A-5,605, 713, Re.33,161, US-A 5,129,905, US-A-5,047,031, EP-A- 416,761, EP-A-543,765, EP-A-664,133 , WO-A-96 36562. These materials can be prepared in the form of a paste capable of being introduced into the bone loss or the bone space to be filled, using a syringe.

  For example, in dental implantology, it is often necessary to resort to a bone graft or the introduction of filling material between the cortex of the sinus and the sinus membrane (Schneider's membrane). This operation increases the bone height when the distance between the crest of the maxilla and the cortex of the sinus is not sufficient to accommodate implants of sufficient length. In periodontology, a loss of bone substance must be filled after debridement of the infosseous pocket.

  On an efficient and rapid ossification of the area thus treated, depends the long-term success of ossification. The most awaited properties of bone filling materials is the possibility that they have to reabsorb as bone is formed and / or to integrate into the bone in formation and / or to serve precursor to this bone in formation. Other expected properties are an adapted hardening capacity, or even physical properties facilitating the placement of the material. The composition of the latter therefore plays an essential role and this is a constant line of research. The work thus relates to the choice of the source of calcium (eg US-A-6,325,992, Re.33, 221), on the addition of additives, such as cohesion promoters and setting accelerators (eg US-A -6,206,957, US-A5,980,625, US-A-5, 952,010), on particle size, on manufacturing processes, etc. There is still a need for improvement of these materials.

  The present invention aims to provide an improvement to bone filling materials, in particular in the field of oral implantology in periodontology and odontology, but not exclusively. The object of the invention is in fact also to be able to be used for bone filling in other traditional fields, and in particular in filling bone losses, in particular on long bones.

  3 2852249 In a completely different field, that of cosmetology, the search for skin regenerative compositions has taken off considerably. One of the lines of research is the stimulation of collagen synthesis. Thus, compounds stimulating the synthesis of collagen by fibroblasts have been described in FR-A-2 682 121, FRA-2 682 038, US-A-6,238,678 and US-A-6,150,403. Such compounds include estrogens (eg estradiol, estriol, estrone) and compounds mimicking estrogens, vitamin D and its precursors and derivatives (eg ergosterol, 7 dehydrocholesterol, vitamin D2, vitamin D3, calcitriol, calcipotriene), Factor X ( kinetin), Factor Z (zeatin), nmethyltaurine, dipalmitoyl hydroxyproline, the compound known as palmitoyl hydroxyl wheat protein (palmitol hydroxyl wheat protein), biopeptide CL (palmitoyl glycylhistidyl-lysine) by Merck Darmstadt under the name ASCIII, beta-glucan (US-A6,238,678). However, it has never been proposed to add this type of compound to bone filling materials.

  The applicant has found that by combining at least one source of calcium and phosphate and at least one compound stimulating the local production of collagen by osteoblasts, a composition capable of contributing to, and of obtaining, is obtained. promote a phenomenon of rapid and effective ossification, making such a composition suitable for serving as a bone filling material in the fields targeted by the invention, namely in oral implantology and in filling bone loss.

  A first object of the invention is therefore a bone filling material, comprising at least one source of calcium and phosphate and at least one compound stimulating the local production of collagen by osteoblasts. In particular, the compound stimulates the synthesis of type III collagen, precursor of type I collagen forming the osteoid matrix.

  The compound stimulating the local production of collagen by osteoblasts is preferably a fatty ester of a hydroxylated amino acid, preferably the fatty esters of hydroxyproline. It can in particular be palmitates, oleates, stearates, mono- or di-. Preferably, it is palmitate or hydroxyproline dipalmitate.

  4 2852249 It may also be a fatty ester of ascorbic acid, in particular palmitate, stearate, oleate, more particularly ascorbic acid palmitate or ascorbyl palmitate, of collagen hydrolyzate palmitate.

  Other suitable compounds are those cited in US-A-6,238,678: estrogens (eg oestradiol, oestriol, oestrone), vitamin D and its precursors and derivatives (eg ergosterol, 7-dehydrocholesterol, vitamin D2, vitamin D3, calcitriol, calcipotriene ), Factor X (kinetin), Factor Z (zeatin), n-methyltaurine, palmitoyl hydroxy wheat protein, biopeptide CL (palmitoyl glycyl-histidyl-lysine), beta-glucan.

  Optionally, this stimulating compound can be formulated in vesicular vectors of the vesicle, capsule, nanocapsule, liposome type. These vectors can in particular have a diameter ranging from 30 to 1000 nanometers. They incorporate the compound either in an aqueous medium filling the interior volume of the vector, or in the wall of the vector. Liposomes and their methods of preparation are well known to those skilled in the art and include multilamellar vesicles (MLV), small unilamellar vesicles (SUV) and large unilamellar vesicles (SUV).

  A person skilled in the art has at his disposal numerous methods making it possible to produce such vectors, e.g. liposomes, and he can use them to incorporate the compounds stimulating the synthesis of collagen according to the invention. An advantageous method for producing liposomes is that described in FR-A-2,649,335 to which a person skilled in the art can refer.

  According to a particular embodiment of the invention, the compound stimulating the synthesis of collagen is formulated in the form of a vector, eg of liposome, in accordance with FR-A-2 682 038 and FR-A-2 682 121, to which the skilled person can refer.

  Those skilled in the art have other well known methods for producing liposomes. For example, the emission of ultrasound by means of a metal probe immersed directly in an MLV suspension is a common way of preparing SUVs. The preparation of MLV type liposomes usually consists of dissolving the lipids in an appropriate organic solvent, then removing the solvent under a stream of air or gas. this results in the formation of a thin film of lipids on the surface of the container. An aqueous solution is then introduced into the container, with stirring, to detach the lipids from the walls of the container. A dispersion of the lipids is obtained, leading to the formation of the liposomes. LUV type liposomes can be produced by slow hydration of a thin layer of lipids, with distilled water or an appropriate aqueous solution. It is also possible to prepare liposomes by lyophilization. Such a method comprises the formation of a lipid film under the action of a stream of nitrogen, then the dissolution of this film by a volatile solvent, followed by freezing and lyophilization making it possible to remove the solvent . Reference may be made to the following journals: Pagano and Weinstein (Ann. Rev. Biophysic, Bioeng., 7, 435-68 (1978)) and Szoka and Papahadjopoulos (Ann. Rev. Biophysic. Bioeng., 9, 467- 508 (1980)).

  According to the preferred embodiment, the compound is hydroxyproline palmitate or dipalmitate, optionally formulated in liposomes, in particular according to the teaching of FR-A-2,682,038 and FR-A-2,682,121. compound formulated as a liposome can be found commercially under the name ASC III (Merck Darmstadt).

  The source of calcium and phosphate comprises one or more calcium phosphates, in particular one or more components chosen from hydroxyapatite HA, dicalcium phosphates (DCP; eg anhydrous dicalcium phosphate or monetite CaHPO4 or dihydrate or brushite CaHPO4. 2H20, phosphates tricalcium (TCP; alpha-Ca3 (PO4) 2 and in particular betaCa3 (PO4) 2), tetracalcium phosphates (TTCP; Ca4 (PO4) 20) and octacalcium phosphates (Ca8H2 (PO4) 6.5H20). tricalcium phosphates modified by the addition of protons or magnesium up to approximately 10% by weight (whitlockite).

  In a first embodiment, a mixture of at least two types of phosphates is used, in particular a mixture comprising hydroxyapatite and a di-, tri- or tetracalcium, in particular tricalcium, phosphate. In a second embodiment, a mixture is used comprising a tetracalcium phosphate and at 6 2852249 minus another phosphate among the di- and tri-calcium. In a particular embodiment, a tetracalcium phosphate and at least one calcium phosphate are used, in particular anhydrous dicalcium phosphate or dicalcium phosphate dihydrate. For more details, a person skilled in the art can refer to US Patent Re.33,221.

  Preferably, the calcium to phosphate ratio of the compositions according to the invention is less than 2.

  The different calcium phosphates present in the same material are preferably in equimolar amounts. The proportions may however vary. For example, for a biphasic, the ratio can range from 1: 1 to 1: 4.

  The compositions according to the invention can especially comprise: - from 40 to 80 or 90% (w / w) of mineral phase (calcium phosphates and possibly other mineral materials), more particularly from 50 to 70%, more particularly still '' around 60%, and / or - from 10 or 20 to 60% of organic phase (compound stimulating the synthesis of collagen, present at 0.01 to 50% of this phase, + excipient, and possible other ingredients such than water, other aqueous medium, additives, eg setting accelerator, cohesion promoter), more particularly from 30 to 50%, more particularly still of the order of 40%.

  The compositions according to the invention can be in different forms.

  It can be a ready-to-use, pasty form. Such a composition then comprises an aqueous excipient. The content of aqueous excipient depends on the viscosity that one wishes to impart to the dough and can be between 0.1 and 1 ml of aqueous excipient for 1 g of calcium and phosphate source, in particular from 0.3 to 0.45 ml / g , preferably between 0.35 and 0.4 ml / g. This makes it possible to obtain a paste which can advantageously be applied using a syringe. The calcium phosphate can have an average particle size of less than 100, in particular to 50, for example less than 20, 10 or 5 μm.

  The composition may also be in powder or granular form and be able to be combined with an aqueous medium in an extemporaneous manner. The calcium phosphate can thus have an average particle size of less than 100, in particular to 50, for example less than 20, 10 or 5 μm.

  The compositions according to the invention can incorporate other ingredients. They can thus comprise one or more cohesion promoters, in particular polymer or oligomer, e.g. celluloses, starches, cyclodextrins, alginates, dextransulphates, polyvinylpyrrolidone, hyaluronic acid. They are advantageously a cellulosic polymer, e.g. hydroxypropylmethylcellulose. The concentration of cohesion promoter can range, for example, from 0.1 to 20%, in particular from 1 to 10% (w / w) of the organic phase relative to the total composition.

  The aqueous medium for taking up the pulverulent material is advantageously a blood product, preferably originating from the patient to be treated. It may be whole blood to which an anticoagulant is added or plasma, in particular plasma enriched with platelets. If necessary, an aqueous medium such as sterile water can be added in addition.

  Blood, plasma and even more platelet rich plasma bring with them what are called platelet growth factors, which are two in number: PDGF (Platelet Derived Growth Factor) and TGF (Transforming Growth Factor Beta ). These factors play an important role in the healing process. PDGF notably activates the cellular multiplication of osteoblasts and TGF 3 that of preosteoblastic cells, while promoting angiogenesis. They therefore activate the healing of mineralized tissues (bone and gum).

  Their addition to the compositions of the invention are therefore a plus in favor of faster and more efficient healing and ossification. It is also also possible to add extemporaneously to a pasty composition according to the invention, plasma rich in platelets. Finally, these growth factors, especially those produced by genetic engineering, can be added directly.

  8 2852249 There are several methods of preparing platelet-rich plasma. The following two methods can be cited.

  For example, 50 to 100 ml of blood is taken from the patient in a bag containing an anticoagulant. The blood is then centrifuged and three layers are obtained: the upper layer consists of platelet-poor plasma, the lower layer essentially contains red blood cells, and the intermediate layer is formed of platelet-rich plasma (high concentration of platelets in plasma). This layer can then be re-coagulated, for example using CaCl2 and bovine thrombin.

  A second, more advantageous method is as follows. For example, 40 to 100 ml of patient's blood is taken in sterile 10 ml tubes, approximately 15 minutes before the end of the surgical intervention. The blood is then centrifuged at 2500 rpm for 12 minutes. It is divided into three layers which are, from top to bottom, platelet-poor plasma, platelet-rich plasma and red blood cells. Platelet rich plasma can be recovered and used.

  In a particular embodiment of the invention, the mixture of calcium phosphate and stimulant of the synthesis of collagen can be done extemporaneously, in the final aqueous medium, in particular in the blood of the patient or in the plasma enriched in platelets.

  The composition according to the invention can therefore be in two-component form, the mineral phase in a first package, the organic phase in a second package.

  The present invention also relates to the method comprising the use of a composition according to the invention as a bone filling material.

  In a first application, the method comprises applying the composition so as to fill all or part of a bone loss. The composition can be applied directly or, in particular in the case of a powdery cement, mixed extemporaneously with an aqueous medium, in particular blood, if possible from the patient, and preferably plasma enriched in platelets. This method can thus replace, or be associated with, conventional autogenous bone grafting techniques. Thus, in a particular embodiment, the composition according to the invention is used in combination with an autogenous bone graft.

  In a second application, the method includes applying the composition to create bone mass. This is particularly applicable to the creation of bone mass in dental implantology. An example of application is the elevation of the sinus floor, when the distance between the crest of the maxilla and the cortex of the sinus leaves little room to accommodate implants of sufficient length. To increase this height, a composition according to the invention is introduced between the cortex of the sinus and the membrane of the sinus. The composition can be applied directly or, in particular in the case of a powdery cement, mixed extemporaneously with an aqueous medium, in particular blood, if possible from the patient, and preferably plasma enriched in platelets. This method can thus replace, or be associated with, conventional autogenous bone grafting techniques. Thus, in a particular embodiment, the composition according to the invention is used in combination with an autogenous bone graft.

  In a second, more general object, the invention relates to the use of such a stimulating compound to stimulate the synthesis of collagen by osteoblasts.

  The present invention also relates to the use of calcium phosphate and stimulant of collagen secretion, eg in the form of a composition as described, for the preparation of a bone filling cement or of a cement intended to create bone mass. The various characteristics mentioned with regard to the compositions, their extemporaneous preparation and the methods of application find their application in this other object of the invention.

  The invention will now be described in more detail using embodiments taken by way of nonlimiting examples.

  The calcium phosphates can be prepared according to the usual techniques such as those described in: McDowel et al., Inorg. Chem. 1971, 10: 1638-1643 2852249 Gregory et al., J. Res. Nat. Off. Stand. 1974, 78A: 667-674; Moreno et al., Soil Sci. Soc. Am. Proc. 1960, 21: 99-102; Brown et al., J. Res. Nat. Off. Stand. 1965, 69A: 547-551; Patel at al., J. Res. Nat. Off. Stand. 1974, 78A: 675-681; or processes described in the aforementioned patents, in particular US-A-6,325,992, Example 1 which describes a method of preparing a tetracalcium phosphate having a Ca / P ratio of less than 2. Usable calcium phosphates are also described in Grimandi et al. ., J. Biomed. Mater. Res. 1998, 39: 660-666; Gauthier et al. , J. Periodontol. 1999, 70: 375-383.

  Calcium phosphates can also be commercial products, e. g. tricalcium phosphate sold under the name calcium phosphate tribasic by Mallinckrodt Baker Inc., Phillipsburg, New Jersey, USA (CAS no 1306-06-5), or tricalcium phosphate marketed by Astaris, LLC, St-Louis, Missouri, USA ( CAS n 62974-97-4).

  The calcium phosphates can optionally be dehydrated, for example around 120 C. The calcium phosphates obtained can be ground to obtain the desired particle size.

Example 1

  An equimolar mixture of calcium phosphate is produced comprising tetracalcium phosphate (5 g) and dicalcium phosphate (5 g). To this mixture, 0.1 g, 0.5 g or 1 g of hydroxyproline dipalmitate is added.

  The material thus obtained is mixed either with the blood of the patient to be treated, or with platelet-rich plasma prepared from this blood, until a homogeneous paste is injectable using a syringe.

Example 2

  An equimolar mixture of calcium phosphate is produced comprising tetracalcium phosphate (5 g) and beta tricalcium phosphate (5 g). To this mixture, 0.1 g, 0.5 g or I g of hydroxyproline dipalmitate is added.

  1 1 2852249 The material thus obtained is mixed either with the blood of the patient to be treated, or with plasma rich in platelets prepared from this blood, until a homogeneous paste is injectable using a syringe. .

Example 3

  An equimolar mixture of calcium phosphate is produced comprising tetracalcium phosphate (5 g), dicalcium phosphate (5 g) and beta-tricalcium phosphate (5 g). To this mixture, 0.15 g, 0.75 g or 1.5 g of hydroxyproline dipalmitate is added.

  The material thus obtained is mixed either with the blood of the patient to be treated, or with platelet-rich plasma prepared from this blood, until a homogeneous paste is injectable using a syringe.

Example 4

  The mixtures of calcium phosphate and hydroxyproline dipalmitate of the preceding examples are added with an aqueous excipient, so as to form a homogeneous paste ready for use.

Example 5:

  Liposomes containing hydroxyproline dipalmitate are prepared, according to the method described in FR-A-2 649 335 and by reproducing the specifications of example 1 of FR-A-2 649 335, replacing vitamin E by the dipalmitate hydroxyproline.

  10 g of calcium phosphate according to example 1, 2 or 3 and 10 g of liposomes are then mixed.

  The material thus obtained is mixed either with the blood of the patient to be treated, or with platelet-rich plasma prepared from this blood, until a homogeneous paste is injectable using a syringe.

  It should be understood that the invention defined by the appended claims is not limited to the particular embodiments indicated in the description above, but encompasses variants thereof which do not depart from the scope or the spirit of the present invention.

13 2852249

Claims (9)

claims   1. Composition usable in particular as a bone filling material, in particular in oral implantology, comprising at least one source of phosphate and calcium and at least one compound stimulating the local production of collagen by osteoblasts.   2. Composition according to Claim 1, characterized in that the compound stimulating the local production of collagen by osteoblasts comprises a fatty ester of a hydroxylated amino acid, preferably a fatty ester of hydroxyproline, in particular mono- or di- palmitate, -oleate, - stearate; a fatty ester of ascorbic acid, in particular palmitate, stearate, oleate, preferably palmitate of ascorbic acid; collagen hydrolyzate palmitate; vitamin D or one of its precursors or derivatives, Factor X; Factor Z; n-methyltaurine; palmitoyl-hydroxyl wheat protein; palmitoyl glycylhistidyl-lysine; beta glucan.   3. Composition according to claim 2, characterized in that the compound stimulating the local production of collagen by osteoblasts comprises palmitate or hydroxyproline dipalmitate.   4. Composition according to one of claims I to 3, characterized in that the compound stimulating the local production of collagen by osteoblasts is formulated in vesicular vectors.   5. Composition according to one of claims 1 to 4, characterized in that it comprises one or more components chosen from hydroxyapatite, dicalcium phosphates, tricalcium phosphates, tetracalcium phosphates and octacaic phosphates.   6. Composition according to claim 5, characterized in that it comprises at least two types of calcium phosphates, and preferably with a tetracalcium phosphate or a tricalcium phosphate beta.   7. Composition according to one of claims 1 to 6, characterized in that the calcium to phosphate ratio is less than 2.   8. Composition according to one of claims 1 to 7, characterized in that it comprises a polymeric or oligomeric cohesion promoter, preferably a cellulose polymer.   14 2852249 9. Composition according to one of claims 1 to 8, characterized in that it comprises one or more platelet growth factors.