BR102013000771A2 - Fiber Filling for Bone Defect Filling - Google Patents

Abstract

Antimalarial pharmaceutical composition, process for obtaining and using it. The present invention provides an anti-malarial pharmaceutical composition comprising 1,5-diaryl penta-3-one as an alternative for malaria control. It also provides a process for obtaining and using it. More specifically, the present invention brings the development of a high potential composition against malaria, involving in its synthesis, low cost reagents and solvents, little or no residue generation, reduced number of steps, easy handling of reagents, They are crystalline for easy purification and their preparation is reproducible on a large scale.

Description

FILLING FIBERS FOR FILLING BONE DEFECTS

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation order in part of US Patent Application No. 12 / 707,302 filed February 17, 2010, which claims priority of Japanese Patent Application 2009-163320 filed July 10, 2009. The present application claims the priority of these two previous applications and Japanese Patent Application No. 2011-021790, filed February 3, 2011. The contents of these three previous applications are incorporated herein by reference in their entirety.

FIELD OF THE INVENTION The present invention relates to bioactive materials which are useful as bone repair materials for filling bone defects and may be used in fields such as maxillofacial surgery and orthopedic surgery. More specifically, the present invention relates to a fiber filler for filling bone defects. The fiber filler has a three-dimensional structure, and comprises a bioresorbable biodegradable resin.

BACKGROUND OF THE INVENTION

Some materials, when grafted or implanted into bone defects, react with bone and are chemically combined directly with bone. These materials are called bioactive materials and are further classified into surface bioactive materials, characterized by the fact that the reaction occurs only on the surface of the materials, and the bioabsorbable materials, characterized by the fact that the reaction occurs even within the materials and The materials are gradually replaced with the bone. Exemplary marketed surface bioactive materials include hydroxyapatite ceramics (e.g., APACERAM ™ trade name provided by Hoya Corporation, Japan); and examples of commercially available bioabsorbable materials include beta phase tricalcium phosphate ceramics (e.g., OSferion ™ trade name provided by Olympus Terumo Biomaterials Corp., Japan).

Calcium carbonate (CaC03) and plaster (CaS04H20) are also known to be resorbable. These substances, however, have low strength and hardness and are difficult to machine. In contrast, biodegradable polymers such as poly (lactic acid (s)), poly (glycolic acid (s)), copolymers thereof, and polycaprolactones are highly flexible and are easy to machine. Biodegradable polymers, however, do not have osteogenic capacity (bone formation capacity), because their biodegradability is derived from the phenomenon that they are degraded in vivo and are discharged from it. In addition, there are some reports that some of the biodegradable polymers may affect surrounding tissues because they are typically degraded to lactic acid or glycolic acid upon degradation and thus show acidity. Under such circumstances, investigations have been made to provide composite materials between these inorganic compounds and organic compounds to enable the composite materials to have both osteogenic ability and biorresorbability and still have improved mechanical properties. For example, Japanese Unexamined Patent Application Publication (JP-A) No. 2001-294673 discloses a process for preparing a resorbable material by combining a poly (lactic acid) and a calcium carbonate. Specifically, this document relates to a process for synthesizing a bioresorbable material by mixing a vaterite phase calcium carbonate as a major component with a biodegradable polymeric compound such as a poly (lactic acid), the vaterite being highly soluble. in water between such calcium carbonates. This technique is also advantageous in that the pH is always maintained around neutrality, because even when the poly (lactic acid) is decomposed to be acid, the acidity is neutralized by the buffering effects of calcium carbonate as dissolved.

In this unprecedented aging society, bone defects should desirably be healed as soon as possible, as it is very important to maintain and ensure chewing and exercise performance for health. In order to improve osteogenic capacity, incorporation of a bioresorbable membrane, a factor such as an inducer of bone formation, has been attempted (see Japanese Patent Application Publication (JP-A) No. H06 (1994) -319794), or a proliferating factor or a bone morphogenic protein (see Japanese Unexamined Patent Application Publication (PCT) (JP-A) number 2001-519210 and Japanese Unexamined Patent Application Publication (JP-A) number 2006-187303). However, it is difficult to deal with these factors. Accordingly, demands have been made to develop a resorbable material having superior bone reconstruction capability to enable bone to self-regenerate more reliably and more rapidly.

In view of recent research trends and technologies for related biomaterials, the mainstream research has shifted from a material design for bonding a material to bone to a material design for bone regeneration; In this research, the role of silicon in bone formation has received much attention, and several silicon-doped materials have been designed (TSURU Kanji, OGAWA Tetsuro and Ogushi Hajime, "Recent Trends in Bioceramics Research, Technology and Standardization", Ceramics Japan, 41, 549-553 (2006)). For example, it has been reported that controlled release of silicon may act on cells to promote bone formation (Maeda Η., T. Kasuga, and L.L

Hench: "Preparation of Poly (L-lactic acid) -Polysiloxane-Calcium Carbonate Hybrid Membranes for Guided Bone Regeneration", Biomaterials, 27, 1216-1222 (2006)). Independently, when compounds of a poly (lactic acid) with one of three types of calcium carbonate (calcite, aragonite and vaterite) are prepared and embedded in a simulated body fluid (SBF), the poly (lactic acid) compound , with vaterite forms a hydroxyapatite having bone-like composition and dimensions within a short time between the three composites (H. Maeda, T. Kasuga, M. Nogami, and Y Ota, "Preparation of Calcium Carbonate Composite and Their Apatita"). Forming Ability in Simulated Body Fluid ", J. Ceram. Soc. Japan, 112, S804-808 (2004)). These results demonstrate that the use of vaterite, which can gradually release silicone, is believed to be the key to obtaining a material that produces faster bone reconstruction.

To use a bone defect filler material, the affected area (bone defect) is incised and a dense or porous material, such that it fills the affected area sufficiently, is directly implanted or a granular material is loaded into the affected area.

To ensure bone formation, it is desirable to implant or fill such material in the affected area without an opening (gap). However, it is not easy to process a dense or porous material to fit the dimensions of the affected area comfortably. In addition, granular material that is loaded into the affected area often shifts out of the affected area after surgery (implantation). These techniques are therefore susceptible to improvement.

Independently, the guided bone regeneration technique that uses a masking membrane to cover a bone defect is also known. The guided bone regeneration technique does not involve the loading of a material in the affected area. Instead, this technique uses a masking membrane, which has the functions of preventing invasion of cells and tissues that are not involved in bone formation within the bone defect, allowing the bone's self-regenerating ability to expose, and help rebuilding the bone. This technique is intended to heal the bone defect by utilizing the healing ability that a living body inherently has. For example, Japanese Unexamined Patent Application Publication (JP-A) No. 2009-61109 discloses a guided bone regeneration membrane and a method of production thereof, characterized in that the guided bone regeneration membrane has a structure of A double layer, including a first layer of non-woven fabric and a second layer of non-woven fabric, characterized in that the first layer of non-woven fabric contains calcium carbonate releasable silicon and a biodegradable resin as main components, and The second layer of nonwoven fabric contains a biodegradable resin as a major component. The use of this membrane has been reported to provide satisfactory proliferation of osteoblast-like cells in mice (MC3T3-E1 cells), and when a bone defect formed in a rabbit skull bone is coated with such a membrane, satisfactory bone formation (osteogenesis ) is observed (see T. Wakita, A. and T. Obata Kasuga "Neur Fabrication Process of Layered Membranes Based on Poly (Lactic Acid) Fibers for Guided Bone Regeneration", Materials Transactions, 50 [7], 1737-1741 (2009 )). This membrane, however, is not used as a bone defect filling material because it has a small thickness of 230 to 300 μπι. In addition, the apparent density of such membranes, estimated at about 0.4 g / cm3 or more, is generally too high to be used as a bone defect filler material.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide a fiber filler formed of a resorbable bone defect filler material, the material having a sustained release system having such chemical composition in order to effectively guide the bone reconstruction capacity and It has a three-dimensional structure having a flexibility such as to fit into an affected area satisfactorily.

In one aspect, the present invention relates to a fiber filler for bone defect filler, characterized in that the fiber filler has a three-dimensional flocculation structure including a plurality of fibers. The fibers contain a biodegradable resin as a major component and contain or carry a siloxane.

In one aspect, the fibers in a fiber filler of the present invention may be coated with hydroxyapatite on their surfaces. The biodegradable resin may be poly (lactic acid) or a copolymer thereof. The fibers may contain siloxane dispersed in calcium carbonate microparticles.

In one aspect, the present invention relates to a bone defect fiber filler comprising a plurality of fibers consisting of a biodegradable resin and vaterite phase calcium carbonate microparticles, characterized in that the various fibers are tangled. each other three-dimensionally to form a fiber fill such that the bulk density of the fiber fill is from 0.005 to 0.3 g / cm 3.

In one aspect, the present invention relates to a bone defect fiber filler comprising various biodegradable fibers containing various calcium carbonate and siloxane microparticles. Biodegradable fibers are entangled three-dimensionally to create three-dimensional spaces of about several tenths of a micrometer or more across the fiber filler structure, such that the fiber filler has sufficient flexibility in all three-dimensional directions to form a fiber. flat track structure. The bulk density of the fiber fill as measured according to JIS L 1097 is from about 0.005 to about 0.3 g / cm3.

In one aspect, the present invention relates to a bone defect fiber filler comprising various biodegradable fibers containing various calcium carbonate and siloxane microparticles. Biodegradable fibers are entangled three-dimensionally to create three-dimensional spaces of about several tenths of a micrometer or more across the fiber filler structure, such that the fiber filler has sufficient flexibility in all three-dimensional directions to form a fiber. flat track structure. The bulk density of the fiber fill as measured according to JIS L 1097 is from about 0.005 to about 0.3 g / cm3.

In one aspect, the present invention relates to a bone defect fiber filler comprising various fibers containing a biodegradable resin, vaterite phase calcium carbonate microparticles and siloxane. The various fibers are tangled together in the three dimensional directions to create a fiber filler structure such that the fiber filler exhibits substantially the same flexibility in all three dimensional directions. The bulk density of the fiber filler is from 0.005 to 0.3 g / cm3, the fiber fill compressibility as measured according to JIS L 1097 is from about 10% to about 55% and the compression recovery. of the fiber fill as measured according to JIS L 1097 is from about 5% to about 76%.

BRIEF DESCRIPTION OF DRAWINGS

Other objects, features and advantages of the present invention will be more fully understood from the following detailed description with reference to the accompanying drawings.

In the drawings: Figure 1 shows an explanatory view of a common electrostatic deposition technique; Figure 2 shows an explanatory view of an electrostatic deposition technique according to one embodiment of the present invention; Figure 3 illustrates the appearance of a three-dimensional structure of a fiber filler prepared in Example 1, indicated as 10 square millimeters; Figure 4 shows a scanning electron micrograph (SEM) of fibers constituting the three-dimensional structure of a fiber filler prepared in Example 1; Figure 5 is a graph showing the amount of silicon ions released from a three-dimensional Si-PLA15 structure prepared in Example 1 in a cell culture medium; Figure 6 is a graph showing the amount of silicon ions released from a three-dimensional Si-PLA50 structure prepared in Example 1 in a cell culture medium; Figure 7 shows a scanning electron micrograph (SEM) of fibers constituting a three-dimensional Si-CaC03 / PLA structure prepared in Example 2; Figure 8 shows a scanning electron micrograph (SEM) of fibers constituting a three-dimensional Si-CaC03 / PLA structure obtained after immersion in 1.5 FBS, the Si-CaC03 / PLA three-dimensional structure prepared in Example 2; Figure 9 illustrates an X-ray diffraction pattern of the three-dimensional Si-CaC03 / PLA structure prepared in Example 2, before and after SBF 1.5 immersion; Figure 10 is a graph showing the cell proliferation test results of a three-dimensional hydroxyapatite coated Si-CaC03 / PLA structure prepared in Example 2 and a comparison sample. Figure 11 shows a SEM photograph of calcium carbonate releasable silicon microparticles obtained by the carbonation process. Figure 12 shows an explanatory view of an electrostatic deposition technique according to one embodiment of the present invention; Figure 13 (A) shows an explanatory view of the fiber fill volume density measurement prepared in Example 3. Figure 13 (B) shows an explanatory view of the fiber fill compressibility measurement prepared in Example 3; characterized by the fact that weight is placed on the lid. Figure 13 (C) is an explanatory view of the fiber fill compression recovery measurement prepared in Example 3, characterized in that the weight is removed from the cap.

DETAILED DESCRIPTION The present invention will be further described with reference to the various embodiments of the drawings. Embodiments of the present invention relate to bioactive materials for filling bone defects. The materials comprise fiber filler. Such material has a three dimensional flocculant structure of a fibrous substance comprising a biodegradable resin as a major component. The fibrous substance contains or carries a siloxane.

As used herein, a three-dimensional (3D) structure is a soft, loose 3D structure. A biomaterial of the invention having such a soft and loose 3D structure can be defined by various physical / chemical parameters such as its weight, bulk density, compressibility, compressibility, as described herein. These physical / chemical parameters can be determined using known standard methods, such as the Japanese Industrial Standard (JIS) methods, in particular the JIS L 1097 method.

A siloxane is any chemical compound consisting of units of the form (R2SiO) n, characterized in that R is a hydrogen atom or a hydrocarbon group (eg methyl, ethyl, propyl and butyl). Siloxane has a backbone comprising alternately Si and O. A siloxane suitable for use with the embodiments of the invention may be any siloxane which may release Si in vivo. See, for example, Wakita et al., "Preparation of electrospun siloxane-poly (lactic acid) -vaterite hybrid fibrous membranes for guided bone regeneration," Compos. Know. Technol., 2010; 70: 1889-1893.

Bioactive materials of the present invention may be prepared using electrostatic deposition techniques. Electrostatic deposition uses an electric charge to drag very thin fibers (typically on the micro or nano scale) of a liquid or paste. When a sufficiently high voltage is applied to a drop of liquid, the body of the liquid becomes charged. Electrostatic repulsion on the drop could counteract surface tension and the droplet would be stretched. When the repulsive force exceeds surface tension, a stream of liquid erupts from the surface. This eruption point is known as a Taylor cone. If the molecular cohesion of the liquid is sufficiently high, the current does not break and a jet of charged liquid is formed. After the jet dries in flight, the flow current mode changes from ohmic to convective as the charge migrates to the fiber surface. The jet is then lengthened by a beating process caused by electrostatic repulsion initiated with small bends in the fiber until it is finally deposited on a grounded manifold. The elongation and thinning of the fiber resulting from this bending instability leads to uniform fiber formation with nanometer scale diameters.

While the voltage is normally applied to the solution or suspension in a regular electrostatic deposition process according to the embodiments of the present invention, the voltage is applied to the collector rather than to the polymer solution (or suspension), and therefore The polymer solution is grounded. The polymer solution or paste is sprayed into the fibers while applying tension in this manner, and the fibers are interlaced to form a three dimensional structure.

Alternatively, a bone defect filling material having a three-dimensional structure and being satisfactorily flexible can also be obtained by performing the improved electrostatic deposition technique, followed by immersion of the electrorotated material in a buffer solution that is supersaturated with hydroxyapatite.

Examples of biodegradable resins usable with the embodiments of the invention include synthetic polymers such as polyethylene glycols (PEGs), polycaprolactones (PCLs), poly (lactic acid) (PLAs), polyglycolic acids (PGAs) and PEG and PCL copolymers, as well as Natural polymers such as fibrin, collagen, alginic acid, hyaluronic acid, chitin and chitosan. Preferred examples of the biodegradable resin include a (lactic acid), poly (PLA), and a copolymer of a poly (lactic acid) and a poly (glycolic acid) (PGA) (i.e. lactic acid-glycolic acid copolymer) .

According to embodiments of the invention, a bone defect filler material may be produced as follows. Initially, a solution is prepared by dissolving a biodegradable resin (e.g. PLA) in a suitable solvent, eg chloroform (CHCl3) and / or dichloromethane. An aqueous solution of aminopropyltriethoxysilane (APTES) is added to the solution. In this procedure, the weight ratio of PLA: APTES (PLA to APTES) is possibly from 1: 0.01 to 1: 0.5, but is preferably from 1: 0.01 to 1: 0.05 (by weight). ). This is because most APTES, if added in an excessively large amount, dissolve in the initial phase of immersion in the aqueous solution and are therefore not as effective. PLA has a molecular weight of about 20 x 104 to about 30 x 104 kDa. The concentration of PLA in the solution is preferably from 4 to 12 weight percent for satisfactory wiring. In order to maintain satisfactory spinning conditions, dimethylformamide and / or methanol may be added to the solution in a ratio of about 50 weight percent or less relative to chloroform and / or dichloromethane.

A liquid having a relative dielectric constant greater than that of the biodegradable resin may be added to the resulting solution to produce a spinning solution for the preparation of a three dimensional structure. Typically, when the biodegradable resin is a poly (lactic acid), a liquid having a relative dielectric constant greater than that of lactic acid may be added. Examples of liquids with a relative dielectric constant greater than lactic acid (relative dielectric constant: 22.0) include methanol (relative dielectric constant: 32.6), ethanol (relative dielectric constant: 24.6), ethylene glycol (constant relative dielectric: 37.7), 1,2-propanediol (relative dielectric constant: 32.0), 2,3-butanediol, glycerol (relative dielectric constant: 42.5), acetonitrile (relative dielectric constant: 37.5) , propionitrile (relative dielectric constant: 29.7), benzonitrile (relative dielectric constant: 25.2), sulfolane (relative dielectric constant: 43.3), and nitromethane (relative dielectric constant: 35.9). Either of these is effective, but more advantageously water (relative dielectric constant: 70 to 80) can be used. However, water is immiscible and completely separated from chloroform and / or dichloromethane used as a solvent for PLA. To avoid this problem, an amphiphilic liquid such as methanol, ethanol, propanol and / or acetone preferably coexists with the solvent and water. Such amphiphilic liquids for use in the invention are not limited in their relative dielectric constants as they are amphiphilic and satisfactorily both miscible with the solvent (such as chloroform and / or dichloromethane) and water. By way of example, 0.5 to 5 g of amphiphilic liquid (such as methanol, ethanol, propanol and / or acetone) and 0.5 to 3 g of water may be added by 1 g of PLA. The spinning solution may be further combined with a calcium carbonate to form a spinning paste. This helps to expedite (accelerate) the immersion step of the electrostatically deposited article in a buffer solution that is supersaturated with hydroxyapatite to form the corresponding absorbable hydroxyapatite. Absorbable hydroxyapatite contributes to confer greater initial cell adhesion. The amount of calcium carbonate is possibly 60 percent by weight or less because calcium carbonate, if added in an amount of more than 60 percent by weight, can be difficult to mix with the solution to obtain a homogeneous paste. However, calcium carbonate, if added in an amount of less than 10 weight percent, cannot have its notable advantageous effects. The solution or suspension may further include one or more inorganic substances which are usable without problems in vivo. Examples of such inorganic substances include hydroxyapatite, tricalcium phosphate, calcium sulfate, chloride, sodium phosphate, sodium hydrogen phosphate, calcium hydrogen phosphate, octacalcium phosphate, tetracalcium phosphate, calcium pyrophosphate and calcium chloride.

According to embodiments of the invention, a bone defect filler material may also be a substance that contains a biodegradable resin, such as a major component and additionally contains or carries a siloxane. This substance can be prepared by preparing calcium carbonate having siloxane microparticles dispersed therein (Si-CaCO3), typically by the method described in Japanese Unexamined Patent Application Publication (JP-A) No. 2008-100878, and mixing 60 weight percent or less of PLA-Si-CaC03 microparticles. The amount of Si-CaCO3 microparticles is preferably from 10 to 60 weight percent, relative to PLA, as in calcium carbonate. In order to uniformly disperse the microparticles, the substance is preferably prepared by kneading the PLA and Si-CaCO3 microparticles in predetermined proportions of a heating kneader to obtain a composite. The composite is then dissolved in the solvent to obtain a spinning solution.

According to a common electrostatic deposition technique, as illustrated in Figure 1, a charge is applied by a voltage source 1 to a syringe nozzle 2. In this way, a positive charge is applied to a wiring solution, and the solution It is slowly extruded from the tip of the nozzle.

When the effect of the electric field is greater than the surface voltage, the solution will be stretched in fibers and will shift relative to collector 3, which is connected to a ground electrode. On the way to the collector 3, the solution solvent evaporates, thereby forming a thin layer of non-woven fiber fabric. This technique, however, does not produce a three-dimensional structure even if the spinning conditions change (such as the spinning solution concentration, the type of solvent contained in the solution, the feed rate of the solution, the spinning time, the applied tension and the distance between the nozzle and the collector.This is due to the fact that the residual solution and the resin deposited on the collector 3 are properly charged and repelled.Pulsion prevents deposition in the direction of thickness. In this respect, the fibrous resin derived from the solution deposits in collector 3 would have more solvent evaporated, however, a trace amount of the solution is deposited intact (ie containing the solvent) on collector 3.

In contrast, according to embodiments of the present invention, as illustrated in Figure 2, the three-dimensional fiber filling structure can be formed by performing electrostatic deposition while grounding the syringe nozzle 2 (i.e. without the application of a load to it). At the same time, a positive charge is applied to the collector 3. According to this technique, if a normal spinning solution is slowly extruded from the nozzle tip, the spinning solution would drop into droplets as the solution is not loaded. However, when the spinning solution additionally contains a liquid, such as water, with a relative dielectric constant greater than that of the biodegradable resin, the liquid may be affected by the electric field, and the spinning solution may be attracted to the collector by polarization action. In this case, the spinning solution is not properly charged and easily forms three-dimensional deposits in collector 3 without undergoing electrostatic repulsion. In this process, the liquid (solution) can be divided into two or more wires and dragged from the syringe nozzle 2 towards the collector 3. These wires are interlaced to form a three-dimensional flocculant structure in the collector 3.

In order to allow this phenomenon to occur, however, the spinning solution must have a slightly low viscosity. If the wiring solution has an excessively high viscosity, it cannot reach collector 3 even when affected by the electric field. Accordingly, the diameter of the fibrous substance constituting the three-dimensional structure prepared in accordance with embodiments of the invention may be substantially controlled by the viscosity of the spinning solution. When the spinning solution has an especially low viscosity, the fibrous substance may settle more easily to form a three-dimensional structure and the fibrous substance is more likely to have smaller fiber diameters. Typically, when a spinning solution is prepared by dissolving PLA in chloroform to obtain a solution followed by the addition of ethanol and water, the resulting fibrous substance will have a fiber diameter in the range of about 0.05 pm to about 10 ° C. Yeah. It is acceptable not to apply a positive charge but a negative charge to the collector 3, while the spinning solution may be attracted to the collector by polarization action. The resulting three-dimensional structure of a fiber fill may be cut into a piece of a desired size, and the cut piece may be soaked in a buffer solution containing calcium and phosphate ions and saturated with hydroxyapatite to coat the surface. surface of the fibrous main structure with hydroxyapatite. Examples of the buffer solution for use in the present invention include a Tris buffer solution (pH 7.2 to 7.4) containing ions at a concentration substantially equal to the concentration of the inorganic ion in human plasma (simulated body fluid, or SBF) and a solution (1.5 SBF), containing ions at concentrations 1.5 times those of the SBF. SBF at 1.5 is more advantageous because the fibrous substance can be coated with hydroxyapatite more quickly.

In accordance with the present embodiment, a flexible bone defect filler material is provided, the material having a three-dimensional structure of a fiber filler, including a fibrous substance, wherein the fibrous substance contains a biodegradable resin, represented by poly (acidic). (PLA), as a major component, and additionally contains or siloxane carrier. A filler for bone repair is also provided, wherein the surface of the fibrous substance constituting the three-dimensional structure is coated with hydroxyapatite. Such material, which includes the communication space for cell entry, showing improved fit in the affected area, can easily be prepared by adopting the technique for producing a non-woven fabric through electrostatic deposition to produce the three-dimensional structure. In addition, coating with an absorbable hydroxyapatite can be easily accomplished by dipping the electrostatically deposited article into a hydroxyapatite supersaturated buffer solution and the coated absorbable hydroxyapatite helps provide greater initial cell adhesion. The fiber filling thus obtained for filling bone defects has satisfactory flexibility in all three dimensional directions to fit a bone defect derived from the three-dimensional structure consisting of the fibrous substance. The fiber filling flexibility is substantially the same in all three dimensional directions. Fiber padding does not tend to form a flat mat structure in which the fibers are interlaced and extended in two dimensional directions. Such fiber filling shows the high cell proliferation in the cell affinity assay using osteoblast-like cells (MC3T3-E1 cells) and excellent bone reconstruction capacity. The bulk density of the fiber filler of this embodiment is much smaller than the prior art masking membrane, as disclosed, for example, JP-A 2009-61109.

According to some embodiments of the present invention, the fiber filler fibers are formed of a silicon compound, calcium carbonate releasable silicon and a biodegradable polymer.

Similar to the exemplary embodiment discussed above, vaterite phase calcium carbonate microparticles may be used as calcium carbonate releasable silicon, the Si content thereof may be, for example, 2% by weight (hereinbelow). referred to as 2SiV). As described in detail in Unexamined Japanese Patent Application Publication (JP-A) No. 2008-100878, calcium carbonate releasable silicon can be obtained using the carbonation process, in which carbonate gas is sprayed into a suspension. of a mixture of methanol, quenched lime and organic silicone compound. Figure 11 shows an SEM photograph of calcium carbonate microparticles, which is disclosed in (JP-A) No. 2,008-100878. Although microparticle diameters vary and can be changed by adjusting the production conditions, the preferred range of microparticle diameter is approximately 0.5 to 1.5 µm.

A silicone and calcium carbonate compound released from the biodegradable polymer may be formed by heating / kneading the mixture of vaterite phase silicon powders and polylactic acid or a copolymer of polylactic acid and polyglycolic acid. The molecular weights of the polylactic acid or a polylactic acid and polyglycolic acid copolymer are preferably from 150,000 to 300,000. In order to obtain a desirable elasticity of the fiber filler, the 2 SiV content of the compound is preferably from 30% to 40% by weight. This compound may be dissolved with a solvent (e.g. CHCl 3) to obtain a spinning solution. The spinning solution thus obtained can be transformed into a fiber fill by electrostatic deposition techniques.

In order to process the spinning solution into the fiber fill using electrostatic deposition, as illustrated in Figure 12, a positive voltage is applied to the spinning solution in a state where an ethanol-filled collector container is grounded. The spinning solution is then made into fibers and the fibers undergo electrostatic deposition being attracted and traveling to the collector container while the spinning solution solvent is evaporated in the electric field during the process. These fibers attracted to the collector container are accumulated in the container ethanol to form a cotton-like structure. When changing wiring conditions (such as wiring solution density, solvent type, delivery speed, electrostatic deposition time period, applied voltage, nozzle to ethanol distance in manifold container) , desired fiber fill morphology can be obtained. The outer diameter of the fiber filler of this embodiment is preferably from about 0.05 pm to about 30 pm, preferably from about 0.1 pm to about 20 pm, and more preferably from about 10 pm to about 10 pm. about 20 pm. The bulk density of the fiber fill as measured according to JIS L 1097 is from about 0.005 g / cm3 to about 0.3 g / cm3, preferably from about 0.01 g / cm3 to about 0. 0.1 g / cm3, more preferably from about 0.014 g / cm3 to about 0.021 g / cm3. The fiber fill compressibility of this embodiment is from about 10% to about 55%, preferably from about 20% to about 55%, more preferably from 29% to 55%. The compression recovery of the fiber filler of this embodiment is from about 5% to about 76%, preferably from about 7% to about 76%, more preferably from about 44% to about 58%.

Advantage of the Invention As the fiber filler of the present invention is formed of Si-releasable calcium carbonate and a biodegradable polymer, it shows high cell proliferation and has excellent bone reconstruction capacity. Compared to the masking membrane, the bulk density of a fiber filler of the present invention is very low. In addition, a fiber filler of the present invention is flexible and has excellent elasticity. Therefore, it can be easily filled into bone defects during surgery and can be implanted into bone defects without clearance (spacing).

Example 1 and Example 2 The present invention will be illustrated in more detail with reference to the various examples below, which relate to the methods of producing three-dimensional structures. It should be noted, however, that these examples are illustrated for a better understanding of the present invention and are not intended to limit the scope of the present invention in any way. One skilled in the art will appreciate that various modifications are possible without thereby departing from the scope of the invention.

Raw materials used in Example 1 and Example 2 Poly (lactic acid) (PLA): PLPURASORB PL Poly (L-lactide), with a molecular weight of 20 x 104 to 30 x 104 obtained from PURAC Biochem (a division of CSM ; Netherlands). Chloroform (CHCl3): Analytical grade reagent, 99.0% or greater, obtained from Kishida Chemical Co., Ltd., Japan. Γ-Aminopropyltriethoxysilane (APTES): (TSL8331, 98% or plus, obtained from GE Toshiba Silicones Co., Ltd., Japan).

Siloxane Doped Calcium Carbonate (Si-CaC03): Vaterite containing a siloxane in terms of a silicon ion content of 2.9 weight percent, and prepared using quenched lime (Microstar T; 96% or more; Yabashi Industries Co., Ltd., Japan), methanol (analytical grade reagent of 99.8% or greater purity; Kishida Chemical Co., Ltd., Japan), APTES, and carbon dioxide (highest purity 99.9% liquefied carbon dioxide; Taiyo Kagaku Kogyo KK, Japan).

Electrostatic deposition conditions in Example 1 and Example 2 Wiring solution feed rate: 0.1 mL / minutes, Applied voltage: A voltage has been applied to the plate collector at [25 kV, while nozzle is grounded, Distance between nozzle and plate collector: 100 mm, Spinning time: about 60 minutes Example 1 AFTER (1 g) was added to the ultrapure water (0.5 g) with stirring to provide a solution. The solution was added dropwise to an 8 wt% PLA solution in CHCl 3 to provide an APTES content of 0.015 g and 0.050 g, respectively, followed by stirring. During this procedure, APTES was condensed to provide a siloxane. The resulting mixtures were added with 1.5 g ethanol and 1 g ultrapure water to provide spinning solutions. These spinning solutions were electrostatically deposited and thus yielded three-dimensional structures, each including a fibrous substance containing a biodegradable resin, as a major component and containing or containing a siloxane (hereinafter these steric structures are referred to as Si-PLAis and Si-PLAis). PLA50, respectively). Figure 3 shows the appearance of the resulting three-dimensional structure (Si-PLAis). Figure 4 shows a scanning electron micrograph (SEM) of this steric structure, demonstrating that the structure is a steric structure is a flocculent structure including fibers with diameters of several tens of nanometers to eight micrometers. The structures under this condition have a weight of 40 mg. The structures do not lose their flexibility and elasticity even after they have been soaked in and recovered from a cell culture medium.

Each of the steric structures prepared above was cut into a 10 mm wide, 10 mm long and 1 mm thick piece, embedded in 4 mL α-MEM cell culture medium, maintained at a temperature of 37 ° C. in an incubator, in a 5% carbon dioxide gas atmosphere, and the cell culture medium was exchanged for fresh medium on day 1, day 3, and day 5. Figure 5 and figure 6 show the amounts of release of silicon ions when steric structures were embedded in cell culture medium as measured by inductively coupled plasma emission spectrometry. The data demonstrate that both samples (steric structures) released a large amount of silicon ions on day 1, and thereafter released silicon ions in a significantly decreased amount, but continued to release silicon ions at least until day 7. Si-PLASo released about 6.5 ppm of silicon ions on day 1, but released 1 ppm or less of silicon ions from day 6 to day 7, showing only a slight difference from that in Si-PLAi5.

Example 2 A three-dimensional Si-CaCO3 / PLA structure was prepared by kneading PLA and Si-CaCO3 in a kneader heated at 200 ° C for 15 minutes to provide a Si-CaCO3 / PLA compound containing 40 weight percent. Si-CaCO3; 1.67 g of the Si-CaC03 / PLA compound mixed with 8.33 g of CHCl3 to provide a solution by adding 1.5 g of ethanol and 1 g of ultrapure water to the spinning solution, and subjecting the wiring solution to electrostatic deposition under the above conditions. The prepared three-dimensional structure had a flocculent appearance substantially the same as shown in Figure 3 and had superior flexibility and elasticity. Figure 7 is a scanning electron micrograph (SEM) of the three-dimensional Si-CaC03 / PLA structure, demonstrating that this structure is a steric structure, including fine fibers with diameters from about 0.1 to about 3 pm and particles. spheres of calcium carbonate having diameters of about 1 µm incorporated between the fibers. The fibers have small diameters and the gaps (spacings) between the fibers are large enough of about several dozen micrometers or more to give enough spaces to allow cells to enter them. The amount of silicon ion release from this steric structure was determined by the procedure described in Example 1 to find that the steric structure released silicon ions in amounts of 5.3 ppm on Day 1, 0.8 ppm from day 2. at day 3, 0.4 ppm from Day 4 to day 5, and 0.4 ppm from Day 6 to Day 7, indicating that the release of trace amount of silicon ion continued. The steric structure was cut into a 10 mm wide, 10 mm long and 10 mm thick sample piece, soaked in 40 mL of 1.5 FBS, and kept at 37 ° C for one day. The sample was then recovered from 1.5 FBS and observed under a scanning electron microscope (SEM) to find that many aggregate particles as shown in figure 8 were precipitated and that spaces of about several dozen remained. micrometers to allow cells to enter. Figure 9 shows the x-ray diffraction pattern of the specimen before and after immersion in 1.5 FBS, demonstrating that peaks from hydroxyapatite were observed in the specimen after immersion. These results demonstrate that the surfaces of the fibers constituting the three-dimensional Si-CaC03 / PIiA steric structure can be easily coated with a hydroxyapatite only by immersing the steric structure in 1.5 FBS. Figure 10 shows how cell numbers (in terms of cell number per 1 cm 2) vary after inoculation of murine osteoblast-like cells (MC3T3-E1 cells) on the hydroxyapatite-coated steric structure and on a comparative sample (Thermanox : plastic disc for cell culture). The comparative Thermanox sample was surface treated to improve cell proliferation and for use in cell culture. The data in Figure 10 demonstrate that the stereochemical structure provides much higher cell growth capacity than that of the surface treated comparative sample and is expected to be a material that excels in bone reconstruction capacity.

Conditions for Cell Culture Experiment Cultivation: Cultivation using 24-well plate, Cell Type: murine osteoblast-like cells (MC3T3-E1 cells; Riken Institute of Physical and Chemical Research, Japan). Cell inoculation number: 1 x 104 cells / well.

Medium: α-MEM (containing 10% fetal bovine serum).

Exchange Medium: the day after inoculation, then every other day Sample Piece: The sample a 3D steric structure was cut into a piece 10 mm long, 10 mm wide and 10 mm thick (ie one 10 mm cube). Cell Counting Method: Measurement was performed using Cell Counting Kit-8 (Cell Growth / Cell Toxicity Analytical Reagent; Dojindo Laboratories, Japan) according to the protocols attached to the reagent.

Example 3 Vaterite phase calcium carbonate (18 g) having a silicon content of 2% by weight (2SiV) and medical grade polylactic acid (42 g) were mixed and heated / kneaded at 200 ° C for 45 minutes. They were then cooled a composite (SiPVH composite), where the 2SiV content was 30 wt%. 1 g SiPVH thus obtained is dissolved in chloroform (9.3 g) and stirred to obtain a spinning solution. This spinning solution is charged to an electrostatic deposition machine and undergoes electrostatic deposition to obtain fiber fill under the following conditions.

Electrostatic deposition conditions Feeding speed of spinning solution: 0.2 mL / min, Applied voltage: 17 kV, and a distance between nozzle and manifold (filled with ethanol): about 20 cm, Nozzles: Syringe: 18G .

As shown in Figure 12, the ethanol-accumulated fibers in the collector are recovered from the collector (Figure 12).

Samples 1 to 4 were prepared by filling recovered fibers from the collectors and analyzed. Volume density, compressibility and compression recovery were measured according to JISL1097. 1) Fiber Diameter Fiber diameters were measured using an 18-point laser microscope. While the diameter of each fiber thus measured varied significantly, the diameter distribution range was about 10 μτη ~ 21 pm. 2) Volume density Each of the samples 1 to 4 (average weight: 0,055 g) was placed in a glass cylinder with an internal diameter of 22 mm. The circular glass lid of approximately the same diameter (weight: 1.148 g) was placed over the fiber fill in the glass cylinder. The height of the fiber fill (h0) in the glass cylinder was measured with the lid placed on it. The bulk density of the fiber fill was calculated on the basis of the fiber fill volume thus measured and its weight. (as shown in figure 13 (A)). The result was that although varying significantly between samples, the bulk densities of each sample were as follows: Sample 1: 0.015 g / cm3; Sample 2: 0.014 g / cm3; Sample 3: 0.018 g / cm3; and Sample 4: 0.021 g / cm3 (average: 0.017 g / cm3). 3) Compressibility and compression recovery As shown in Figure 13 (B), a weight of 9.914 g is placed on the glass lid disposed inside the glass cylinder. After 30 minutes had passed, the height of the fiber fill (hi) in the glass cylinder in that state was measured. From the change before and after placing the weight on the cap, the fiber fill compressibility was calculated using the following formula.

Compressibility (%) = (h0-hi) / h0 x 100 The fiber fill compressibility of samples 1 through 4 was: Sample 1: 45.56%, Sample 2: 34.90%, Sample 3: 29.01% , Sample 4: 37.80% (36.82% on average).

Then, as shown in figure 13 (C), the weight is taken from the glass lid. After 30 minutes, the fiber fill height (h2) in the glass cylinder in that state was measured. From the change before and after placing the weight on the cap and removing the weight from the cap, the fiber fill compression recovery was calculated using the following formula: Compressibility Recovery (%) = (h2-hi) / ( h0-hi) x 100 The fiber fill recovery compression of Sample 1 through 4 was as follows: Sample 1: 58.47%, Sample 2: 44.02%, Sample 3: 56.14%, Sample 4 : 57.20% (average 53.96%). JIS Test Method Ll097 - 1982 (confirmed in 2008) The Japanese Industry Standard (JIS) published the L 1097 standard method for the synthetic fiber fill test in 1982, which was confirmed in 2008. The test was conducted in a room with Class 2 standard temperature and humidity (temperature 20 ± 2 ° C, relative humidity 65 ± 2%) according to JIS Z8703 (standard test room condition).

Sample Preparation Remove fill pieces from an unpacked product and leave each piece in the room for more than 8 hours. Then randomly choose samples for testing. The 20 cm x 20 cm test samples are stacked until their weight becomes about 40 g. Parts of the test samples required for conducting the test are left in that state for about one hour.

Tests could include color testing, specific volume (by volume), compressibility (compression, recovery), fiber length, and quality. Test Method Specific Volume (Volume Density) Specific volume is measured by measuring the weight of test samples prepared as described above. A thick plate (a 20 x 20 cm long 0.5 g / cm 2 flat plate) is placed on a test piece and a weight of A (2 kg) is placed on it for 30 minutes. Then the weight is removed and a test sample is left for 30 minutes in that state. This procedure is repeated three times. After weight A is removed and left for thirty minutes in that state, sample heights at all four corners are measured and an average height is obtained. The specific volume is calculated using the following formula. The test should be performed with three samples and an average of three samples is obtained.

Specific volume (cm3 / g) - (20 x 20 x h0) / 10) / W where h0 is an average height value at the four corners of the test sample (mm), and W is the weight of the test sample (g ). The specific volume (cm3 / g) can be readily converted to density values (g / cm3) if desired.

Elasticity ____ of _____ compression ____ (compressibility compression, recovery) Compression elasticity is measured by measuring the height of the four corners of a test piece described above. A dough B (4 kg) is placed over it for 30 minutes. The heights at the four corners are measured. After that, weight B is removed, and the test sample is left for 3 minutes. The heights at the four corners are measured. Their mean values are obtained. Compressibility and compression recovery are calculated according to the following formula. The test is conducted on three samples, and an average of the three samples is obtained.

Compressibility (%) = (h0-hi) / h0) x 100 Compressibility recovery (%) = (h2-hi) / (h0-hi) x 100 ho: average height at all four corners before placing weight B on the same (mm). hi: average height at four corners with weight B placed over them (mm) h2: average height at four corners B after weight B is removed (mm).

While the above description is of preferred embodiments of the present invention, it will be appreciated by one skilled in the art that the invention may be modified or altered without departing from the scope and meaning of the following claims.

Claims (19)

1. Filling of bone defect fibers characterized by the fact that it comprises various biodegradable fibers containing various calcium carbonate and siloxane microparticles, where the biodegradable fibers are three-dimensionally entangled to create three-dimensional spaces of about several tenths of a micrometer. or more throughout the fiberfill structure such that the fiberfill has sufficient flexibility in all three-dimensional directions thereof, and where the bulk density of the fiberfill as measured according to JIS L 1097 is from about 0.005 g / cm3 to about 0.3 g / cm3. Fiber filling according to Claim 1, characterized in that the external diameter of the various biodegradable fibers is from about 0,05 pm to about 30 pm; Fiber filler according to either of Claims 1 and 2, characterized in that the bulk density of the fiber filler as measured according to JIS L 1097 is from about 0.005 g / cm3 to about 0.3 g / cm3. Fiber filler according to Claim 1 or 2, characterized in that the bulk density of the fiber filler as measured according to JIS L 1097 is from about 0.014 g / cm3 to about 0.021 g. / cm3. Fiber fill according to any one of claims 1, 2, 3 or 4, characterized in that the compressibility of the fiber fill as measured according to JIS L 1097 is from about 10% to about 55%. Fiber fill according to any one of claims 1, 2, 3 or 4, characterized in that the compressibility of the fiber fill as measured according to JIS L 1097 is from about 20% to about 55%. Fiber filler according to any one of claims 1, 2, 3 or 4, characterized in that the compressibility of the fiber filler as measured according to JIS L 1097 is from about 29% to about 55%. Fiber fill according to any one of Claims 1, 2, 3, 4, 5, 6 or 7, characterized in that the compression recovery of the fiber fill as measured according to JIS L 1097 is from about 5% to about 76%. Fiber filler according to any one of claims 1, 2, 3, 4, 5, 6 or 7, characterized in that the compression recovery of the fiber filler as measured according to JIS L 1097 is from about 7% to about 76%. Fiber fill according to any one of Claims 1, 2, 3, 4, 5, 6 or 7, characterized in that the compression recovery of the fiber fill as measured according to JIS L 10 97 it is about 44% to about 58%. Filling according to any one of claims 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, characterized in that the biodegradable fibers comprise poly (lactic acid) or a copolymer. the same. Fiber filling according to Claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 11, characterized in that the various fibers are coated with hydroxyapatite. 13. Bone defect fiber filling characterized in that it comprises various biodegradable fibers containing various calcium carbonate and siloxane microparticles, where the various fibers are entangled in three-dimensional directions to form a fiber-filling structure; such that the fiber filler has the same flexibility in all three-dimensional directions thereof, and where the bulk density of the fiber filler is about 0.005 g / cm3-0.3 g / cm3, the compressibility of the fiber filler as measured according to JIS L 1097 is from about 10% to about 55% and the fiber fill compression recovery as measured according to JIS L 1097 is from about 5% to about 76%. Fiber filling according to Claim 13, characterized in that the external diameter of the various fibers is from about 0.05 pm to about 30 pm. Fiber filler according to either of Claims 13 or 14, characterized in that the external diameter of the various fibers is from about 0.1 pm to about 20 pm. Fiber filler according to any one of claims 13, 14 or 15, characterized in that the bulk density of the fiber filler as measured according to JIS L 1097 is about 0.01 pm at about 0.1 g / cm3. Fiber filler according to any one of claims 13, 14, 15 or 16, characterized in that the various fibers are coated with hydroxyapatite. Fiber filler according to any one of claims 13, 14, 15, 16 or 17, characterized in that the biodegradable resin is poly (lactic acid) or a copolymer thereof. Fiber filling according to any one of claims 13, 14, 15, 16, 17 or 18, characterized in that the various fibers contain siloxane dispersed in the vaterite phase calcium carbonate microparticles.