An antibacterial monomer for bone cement, its synthesis method and application

Abstract

The present invention discloses an antibacterial monomer for bone cement, its synthesis method and application, which belongs to the field of medical material technology. The structural formula of the antibacterial monomer for bone cement is: #imgabs0#, and its synthesis method comprises the following steps: 3,4-dichloro-5-hydroxy-5H-furan-2-one is covalently linked to isocyanoethyl methacrylate to obtain an antibacterial monomer for bone cement. The antibacterial monomer for bone cement provided by the present invention is combined with a PMMA skeleton by covalent linkage, so that the antibacterial substance is not released in the body, and is sterilized by contact with bone cement, thereby avoiding the defect of explosive release of antibiotics. The antibacterial monomer is used to prepare non-leaching bone cement, which can solve the defect of explosive release of antibiotics in traditional antibacterial bone cement and has both good compressive strength and antibacterial activity.

Description

Technical Field

[0001] The present invention relates to the technical field of medical materials, in particular to an antibacterial monomer for bone cement and a synthesis method and application thereof. Background Art

[0002] Polymethyl methacrylate (PMMA) bone cement is a commonly used bone defect repair material, widely used for treating vertebral compression fractures and fixating joint prostheses. Currently available PMMA bone cement lacks antimicrobial activity and is prone to postoperative infection, with Staphylococcus aureus being the most common pathogen.

[0003] Traditional antimicrobial bone cements typically incorporate antibiotics into bone cement to create antibiotic-loaded bone cement (ALBC). However, ALBC suffers from a burst release of antibiotics, limiting its use. Therefore, there is an urgent clinical need for the development of novel bone cements with antimicrobial properties.

[0004] Non-leaching bone cement (NLBC) can address the burst release of antibiotics often found in traditional antimicrobial bone cements. However, currently, no NLBC possesses both excellent antimicrobial activity and compressive strength. For example, the compressive strength of NLBC often decreases with increasing antimicrobial monomer content, limiting further research and application of this type of NLBC. Therefore, the present invention aims to develop a novel antimicrobial monomer and, using this monomer, to create a novel antimicrobial NLBC with superior compressive strength. Summary of the Invention

[0005] The object of the present invention is to provide a method for synthesizing an antibacterial monomer for bone cement to solve the problems raised in the above background technology.

[0006] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0007] An antibacterial monomer for bone cement, having the structural formula: .

[0008] Another object of the present invention is to provide a method for synthesizing the above-mentioned antibacterial monomer for bone cement, which comprises the following steps:

[0009] 3,4-dichloro-5-hydroxy-5H-furan-2-one is covalently linked with isocyanoethyl methacrylate to obtain the antibacterial monomer for bone cement.

[0010] Preferably, the method specifically includes the following steps:

[0011] 1 equivalent of isocyanoethyl methacrylate is completely dissolved in a solvent, and then 1.05-1.15 equivalents of 3,4-dichloro-5-hydroxy-5H-furan-2-one is added and stirred for reaction to obtain the antibacterial monomer for bone cement.

[0012] Preferably, the solvent is dichloromethane.

[0013] Preferably, the equivalent ratio of isocyanoethyl methacrylate to 3,4-dichloro-5-hydroxy-5H-furan-2-one is 1:1.1.

[0014] Another object of the present invention is to provide an application of the above-mentioned antibacterial monomer for bone cement in the preparation of bone cement.

[0015] Another object of the present invention is to provide a bone cement comprising a solid phase and a liquid phase, wherein the liquid phase comprises the above-mentioned antibacterial monomer for bone cement.

[0016] Preferably, the mass concentration of the antibacterial monomer for bone cement in the liquid phase is 5%-25%.

[0017] The antimicrobial monomer for bone cement provided by this invention is covalently bonded to the PMMA backbone, preventing the release of antimicrobial substances in the body. Bacterial activity is achieved through contact with the bone cement, thus avoiding the potential for explosive release of antibiotics. Using this antimicrobial monomer in the preparation of non-leaching bone cement can address the explosive release of antibiotics associated with traditional antimicrobial bone cements while also providing excellent compressive strength and antimicrobial activity. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of the antibacterial monomer for bone cement synthesized in an embodiment of the present invention.

[0019] Figure 2 Fourier transform infrared spectra of various bone cements provided in the embodiments of the present invention.

[0020] Figure 3 This is a graph showing the compressive strength test results of various bone cements provided in an embodiment of the present invention.

[0021] Figure 4 This is a graph showing the antibacterial rate test results of various bone cements provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0022] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0023] In one embodiment of the present invention, an antibacterial monomer for bone cement is provided, named 3,4-dichloro-5-hydroxy-5H-furan-2-one ethyl methacrylate, referred to as DHFMA, which is a solid that is easily soluble in methyl methacrylate and has the structural formula: .

[0024] In another embodiment of the present invention, a method for synthesizing the above-mentioned antibacterial monomer for bone cement is also provided, which comprises the following steps:

[0025] 3,4-dichloro-5-hydroxy-5H-furan-2-one is covalently linked with isocyanoethyl methacrylate to obtain the antibacterial monomer for bone cement.

[0026] Specifically, the above synthesis method comprises the following steps:

[0027] 1 equivalent of isocyanoethyl methacrylate is completely dissolved in a solvent, and then 1.05-1.15 equivalents of 3,4-dichloro-5-hydroxy-5H-furan-2-one is added and stirred for reaction to obtain the antibacterial monomer for bone cement.

[0028] The synthetic route of antibacterial monomer for bone cement is as follows: .

[0029] In a preferred embodiment of the present invention, the solvent may be dichloromethane (DCM), but is not limited thereto. Other solvents capable of dissolving isocyanoethyl methacrylate may also be used.

[0030] In a preferred embodiment of the present invention, the equivalent ratio of isocyanoethyl methacrylate to 3,4-dichloro-5-hydroxy-5H-furan-2-one is 1:1.1.

[0031] Another object of the present invention is to provide an application of the above-mentioned antibacterial monomer for bone cement in the preparation of bone cement.

[0032] Another object of the present invention is to provide a non-leaching bone cement (DHFMA-NLBC) containing the aforementioned antimicrobial monomer for bone cement, comprising a solid phase and a liquid phase, wherein the liquid phase includes the aforementioned antimicrobial monomer for bone cement. It should be noted that the other components in the solid and liquid phases are the same as those in existing bone cements and are not an improvement of the present invention and will not be discussed further here.

[0033] The non-leaching bone cement containing the above-mentioned antibacterial monomer for bone cement provided by the embodiment of the present invention has excellent antibacterial activity and mechanical strength, and its excellent performance indicates that it has broad prospects in clinical applications.

[0034] In a preferred embodiment of the present invention, the mass concentration of the antibacterial monomer for bone cement in the liquid phase is 5%-25%.

[0035] The following embodiments are some specific implementation cases of the present invention in practical applications, but are not limited to them.

[0036] Example 1: This example provides an antibacterial monomer for bone cement, the synthesis method of which is as follows:

[0037] Take 1 equivalent of isocyanoethyl methacrylate and completely dissolve it in an appropriate amount of dichloromethane. Then add 1.1 equivalents of 3,4-dichloro-5-hydroxy-5H-furan-2-one and stir the reaction for 12 hours to obtain an antibacterial monomer for bone cement, named 3,4-dichloro-5-hydroxy-5H-furan-2-one ethyl methacrylate (DHFMA).

[0038] Take 10 mg of the above-synthesized DHFMA and dissolve it in 0.5 mL of deuterated chloroform. Perform H NMR spectrum test. The results are as follows: Figure 1 The correctness of the structure was confirmed by H NMR spectroscopy, as shown in Figure 2; the correctness of the structure was confirmed by H NMR spectroscopy, as shown in Figure 2; the correctness of the structure was confirmed by H NMR spectroscopy, as shown in Figure 2; the correctness of the structure was confirmed by H NMR spectroscopy, as shown in Figure 2:

[0039] Example 2: This example provides an antibacterial monomer for bone cement, the synthesis method of which is as follows:

[0040] Take 1 equivalent of isocyanoethyl methacrylate and completely dissolve it in an appropriate amount of dichloromethane. Then add 1.05 equivalents of 3,4-dichloro-5-hydroxy-5H-furan-2-one and stir the reaction for 12 hours to obtain an antibacterial monomer for bone cement, named 3,4-dichloro-5-hydroxy-5H-furan-2-one ethyl methacrylate (DHFMA).

[0041] Example 3: This example provides an antibacterial monomer for bone cement, the synthesis method of which is as follows:

[0042] Take 1 equivalent of isocyanoethyl methacrylate and completely dissolve it in an appropriate amount of dichloromethane. Then add 1.15 equivalents of 3,4-dichloro-5-hydroxy-5H-furan-2-one and stir the reaction for 12 hours to obtain an antibacterial monomer for bone cement, named 3,4-dichloro-5-hydroxy-5H-furan-2-one ethyl methacrylate (DHFMA).

[0043] Example 4: This example provides a bone cement, the preparation method of which is as follows:

[0044] Using polymethyl methacrylate (PMMA) bone cement purchased from Heraeus Medical AG in Germany as the base formula, 18 mg of the above-provided antibacterial monomer for bone cement (DHFMA) was added to 344 mg of the liquid phase of bone cement. After thorough shaking, the mixture was mixed with 638 mg of the solid phase of bone cement and stirred evenly to obtain a mixture. The mixture was then poured into a mold for fixation. After curing, the mold was removed to obtain a cylindrical bone cement sample with a diameter of (6.0±0.1) mm and a height of (12.0±0.1) mm, which was recorded as 5% DHFMA-NLBC.

[0045] Example 5: This example provides a bone cement, the preparation method of which is as follows:

[0046] Using polymethyl methacrylate (PMMA) bone cement purchased from Heraeus Medical AG in Germany as the base formula, 54 mg of the above-provided antimicrobial monomer for bone cement (DHFMA) was added to 308 mg of the liquid phase of bone cement. After thorough shaking, the mixture was mixed and stirred evenly with 638 mg of the solid phase of bone cement to obtain a mixture. The mixture was then poured into a mold for fixation. After curing, the mold was removed to obtain a cylindrical bone cement sample with a diameter of (6.0±0.1) mm and a height of (12.0±0.1) mm, which was recorded as 15% DHFMA-NLBC.

[0047] Example 6: This example provides a bone cement, the preparation method of which is as follows:

[0048] Using polymethyl methacrylate (PMMA) bone cement purchased from Heraeus Medical AG in Germany as the base formula, 90 mg of the above-provided antimicrobial monomer for bone cement (DHFMA) was added to 272 mg of the liquid phase of bone cement. After thorough shaking, the mixture was mixed and stirred evenly with 638 mg of the solid phase of bone cement to obtain a mixture. The mixture was then poured into a mold for fixation. After curing, the mold was removed to obtain a cylindrical bone cement sample with a diameter of (6.0±0.1) mm and a height of (12.0±0.1) mm, which was recorded as 25% DHFMA-NLBC.

[0049] Example 7: This example provides a bone cement, the preparation method of which is as follows:

[0050] Using the existing commercially available polymethyl methacrylate bone cement as the basic formula, 70 mg of the above-provided antibacterial monomer for bone cement was added to 280 mg of the liquid phase of bone cement. After thorough shaking, it was mixed with 650 mg of the solid phase of bone cement and stirred evenly to obtain a mixture. The mixture was then poured into a mold for fixation. After curing, the mold was demolded to obtain a bone cement sample.

[0051] Example 8: This example provides a bone cement, the preparation method of which is as follows:

[0052] Using the existing commercially available polymethyl methacrylate bone cement as the basic formula, 40 mg of the above-provided antibacterial monomer for bone cement was added to 360 mg of the liquid phase of bone cement. After thorough shaking, it was mixed with 600 mg of the solid phase of bone cement and stirred evenly to obtain a mixture. The mixture was then poured into a mold for fixation. After curing, the mold was demolded to obtain a bone cement sample.

[0053] Example 9: This example provides a bone cement, the preparation method of which is as follows:

[0054] Using the existing commercially available polymethyl methacrylate bone cement as the basic formula, 20 mg of the above-provided antibacterial monomer for bone cement was added to 380 mg of the liquid phase of bone cement. After thorough shaking, it was mixed with 600 mg of the solid phase of bone cement and stirred evenly to obtain a mixture; the mixture was then poured into a mold for fixation; after curing, the mold was demolded to obtain a bone cement sample.

[0055] Example 10: This example provides a bone cement, the preparation method of which is as follows:

[0056] Using the existing commercially available polymethyl methacrylate bone cement as the basic formula, 30 mg of the above-provided antibacterial monomer for bone cement was added to 370 mg of the liquid phase of bone cement. After thorough shaking, it was mixed with 600 mg of the solid phase of bone cement and stirred evenly to obtain a mixture. The mixture was then poured into a mold for fixation. After curing, the mold was demolded to obtain a bone cement sample.

[0057] Example 11: This example provides a bone cement, the preparation method of which is as follows:

[0058] Using the existing commercially available polymethyl methacrylate bone cement as the basic formula, 60 mg of the above-provided antibacterial monomer for bone cement was added to 340 mg of the liquid phase of bone cement. After thorough shaking, it was mixed with 600 mg of the solid phase of bone cement and stirred evenly to obtain a mixture; the mixture was then poured into a mold for fixation; after curing, the mold was demolded to obtain a bone cement sample.

[0059] Example 12: This example provides a bone cement, the preparation method of which is as follows:

[0060] Using the existing commercially available polymethyl methacrylate bone cement as the basic formula, 80 mg of the above-provided antibacterial monomer for bone cement was added to 320 mg of the liquid phase of bone cement. After thorough shaking, it was mixed with 600 mg of the solid phase of bone cement and stirred evenly to obtain a mixture. The mixture was then poured into a mold for fixation. After curing, the mold was demolded to obtain a bone cement sample.

[0061] Example 13: This example provides a bone cement, the preparation method of which is as follows:

[0062] Using the existing commercially available polymethyl methacrylate bone cement as the basic formula, 100 mg of the above-provided antibacterial monomer for bone cement was added to 300 mg of the liquid phase of bone cement. After thorough shaking, it was mixed with 600 mg of the solid phase of bone cement and stirred evenly to obtain a mixture; the mixture was then poured into a mold for fixation; after curing, the mold was demolded to obtain a bone cement sample.

[0063] The mechanical properties and antibacterial activity of polymethyl methacrylate (PMMA) bone cement purchased from Heraeus Medical AG in Germany were tested with the 5% DHFMA-NLBC, 15% DHFMA-NLBC, and 25% DHFMA-NLBC bone cements prepared in Examples 4-6. Leachates were prepared for biocompatibility evaluation, as follows:

[0064] 1. PMMA bone cement purchased from Heraeus Medical AG in Germany and the 5% DHFMA-NLBC, 15% DHFMA-NLBC, and 25% DHFMA-NLBC bone cements prepared in Examples 4-6 were thoroughly mixed with potassium bromide at a mass ratio of approximately 1:50, then ground and pressed into samples. The prepared samples were analyzed using Fourier transform infrared spectroscopy (FT-IR). The results are as follows: Figure 2 As shown. Figure 2 It can be seen that the bone cement prepared in the embodiment of the present invention has the characteristic absorption of DHFMA.

[0065] 2. Mechanical strength test is as follows: PMMA bone cement purchased from Heraeus Medical AG in Germany and 5% DHFMA-NLBC, 15% DHFMA-NLBC, and 25% DHFMA-NLBC bone cements prepared in Examples 4-6 (5 samples in each group) were polished with 1000-grit sandpaper until the top and bottom surfaces were parallel. The samples were then incubated at 37°C and 100% humidity for 24 hours. At room temperature, a material testing machine (MTS809, Bose Corporation, USA) was used to draw the deformation-load curve of the bone cement sample at a loading rate of 20 mm / min. The compressive strength of each bone cement sample was calculated from these curves, and the results are shown in Figure 2. Figure 3 All operations were performed in accordance with the requirements and standards of ISO 5833. As can be seen from the figure, the bone cement prepared in the embodiment of the present invention has a high compressive strength.

[0066] Third, the antibacterial activity was evaluated as follows: Staphylococcus aureus (ATCC 25923) was revived and passaged to restore its activity. Bone cement samples were synthesized the day before the experiment and soaked in 3 ml of distilled water for 18 hours to remove unpolymerized DHFMA monomers on the surface. On the day of the experiment, a concentration of (0.5 × 10 8 ) CFU / mL of bacterial suspension. Each bone cement sample was soaked in 1 ml of bacterial suspension and incubated in a CO2 incubator at 37°C for 6 hours. The sample was then removed and gently rinsed with 100 ml of distilled water to remove non-adherent bacteria. The sample was placed in 5 ml of normal saline and sonicated for 3 minutes to remove adherent bacteria. Subsequently, the bone cement sample was removed, and the remaining liquid was retained, 40 microliters was aspirated from it and diluted 100 times. After thorough mixing, 40 microliters was aspirated from the diluted bacterial solution and evenly spread on the culture dish. The culture dish was incubated in a CO2 incubator at 37°C for one day, and the colony count was performed to calculate the surface antibacterial rate of bone cement containing different concentrations of DHFMA. Each concentration of bone cement was tested five times. The formula for calculating the antibacterial rate is as follows: ;

[0067] Wherein, A represents the number of colonies on the culture dishes of the control group bone cement, and B represents the number of colonies on the culture dishes of the groups with different concentrations of DHFMA bone cement.

[0068] PMMA bone cement purchased from Heraeus Medical AG in Germany was used as a control group. The antibacterial rate of 5% DHFMA-NLBC, 15% DHFMA-NLBC, and 25% DHFMA-NLBC bone cements prepared in Examples 4-6 were tested according to the above antibacterial activity evaluation method. The results are as follows: Figure 4 As shown in the figure, the bone cement prepared in the embodiment of the present invention has good antibacterial activity.

[0069] In summary, the present invention discloses for the first time a novel antimicrobial monomer, DHFMA, comprising a polymerizable acrylic acid unit and an antimicrobial-active 3,4-dichloro-5-hydroxy-5H-furan-2-one unit. Furthermore, the bone cement prepared in this invention exhibits compressive strength that meets ISO 5833 standards, and both compressive strength and antimicrobial activity increase with increasing DHFMA addition, demonstrating both excellent compressive strength and antimicrobial activity.

[0070] Based on the above-mentioned ideal embodiment of the present invention, and through the above description, relevant personnel can make various changes and modifications without departing from the scope of the technical concept of the present invention. The technical scope of the present invention is not limited to the contents of the specification.

Claims

1. A non-leaching bone cement comprising a solid phase and a liquid phase, characterized in that: The liquid phase includes an antibacterial monomer for bone cement; the mass concentration of the antibacterial monomer for bone cement in the liquid phase is 5%-25%; the structural formula of the antibacterial monomer for bone cement is: ; The synthesis method of the antibacterial monomer for bone cement comprises the following steps: 3,4-dichloro-5-hydroxy-5H-furan-2-one is covalently linked with isocyanoethyl methacrylate to obtain the antibacterial monomer for bone cement.

2. The non-leaching bone cement according to claim 1, characterized in that The specific steps include: 1 equivalent of isocyanoethyl methacrylate is completely dissolved in a solvent, and then 1.05-1.15 equivalents of 3,4-dichloro-5-hydroxy-5H-furan-2-one is added and stirred for reaction to obtain the antibacterial monomer for bone cement.

3. The non-leaching bone cement according to claim 2, characterized in that The solvent is dichloromethane.

4. The non-leaching bone cement according to claim 2, characterized in that The equivalent ratio of isocyanoethyl methacrylate to 3,4-dichloro-5-hydroxy-5H-furan-2-one is 1:1.1.

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