Antibacterial absorbable bone wax and preparation method thereof

Abstract

The invention relates to antibacterial absorbable bone wax and a preparation method thereof. The bone wax comprises the following raw material components in parts by weight: 20-90 parts of a lysine or polylysine modified matrix material, 2-20 parts of an auxiliary material and 0.5-10 parts of an emulsifier. Compared with the prior art, the bone wax product provided by the invention can simultaneously realize various properties such as degradation, osteogenesis and antibiosis, and the popularization and application of the bone wax product are promoted.

Description

Technical Field

[0001] This invention belongs to the field of medical materials technology and relates to an antibacterial absorbable bone wax and its preparation method. Background Technology

[0002] Effective hemostasis of fracture site bleeding during orthopedic surgery has long been a challenge. Excessive bleeding not only affects vital signs but also obstructs vision, hindering the surgeon's work. Bone wax is a commonly used hemostatic material in surgery, controlling bleeding on the bone surface through physical sealing. Traditional bone wax products, composed of beeswax and softeners (such as petroleum jelly), have good biocompatibility and hemostatic effects. However, traditional bone wax is non-absorbable, becoming a permanent residue that inhibits bone defect repair at the application site. Furthermore, bone wax residue can become a permanent source of infection, which is often chronic and difficult to treat effectively with conventional methods. Therefore, the market urgently needs a novel bone wax product that combines hemostasis, biodegradability / absorbability, bone-promoting properties, and antibacterial effects.

[0003] To address the problems associated with traditional bone wax, researchers have been exploring alternative materials, such as synthetic polymers and naturally extracted polymers. These alternatives include synthetic biodegradable polymers like polylactic acid, polyglycolic acid, and polyethylene glycol, and bone wax products made from naturally extracted polymers like carboxymethyl cellulose, sodium alginate, and gelatin.

[0004] Chinese patent CN102579162A discloses an absorbable implant and a method for using them for hemostasis and treatment of bone defects. The implant is composed of a putty-like composition of carboxymethyl cellulose and hydroxyl compounds, with hydroxyapatite and mineralized protein added as bone-promoting components. This implant exhibits good hemostatic effects and can improve bone healing.

[0005] Chinese patent CN109908397A discloses an absorbable hemostatic bone wax and its preparation method. The main components of the bone wax are polycaprolactone and polyethylene glycol, with the addition of hydroxyapatite or β-tricalcium phosphate to promote osteogenic formation and thrombin to accelerate hemostasis. This bone wax has good hemostatic effect and is also completely degradable.

[0006] Chinese patent CN111921002A discloses a method for preparing an antibacterial and osteogenic absorbable bone wax. The main component of this bone wax is an epoxy alkyl copolymer, and the additives include osteogenic components such as calcium sulfate, and antibacterial components such as copper chloride. This bone wax has good plasticity, hemostatic ability, and a certain osteogenic capacity.

[0007] Although various new bone wax products have been developed, it is difficult to simultaneously satisfy the requirements of biodegradability, osteogenic properties, and antibacterial properties. In particular, bone wax products with antibacterial properties rely on the addition of antibacterial adjuvants. This formulation transforms bone wax products from medical devices into drug-device combination products, increasing the difficulty of obtaining approval from the drug regulatory authorities. Summary of the Invention

[0008] The purpose of this invention is to provide an antibacterial absorbable bone wax and its preparation method, so as to simultaneously achieve the three properties of degradation, osteogenic and antibacterial.

[0009] The objective of this invention can be achieved through the following technical solutions:

[0010] On one hand, the present invention provides an antibacterial absorbable bone wax comprising the following raw material components in parts by weight: 20-90 parts of lysine or polylysine modified matrix material, 2-20 parts of excipients, and 0.5-10 parts of emulsifier.

[0011] Furthermore, the matrix material is one or more of polylactic acid, polyglycolic acid, polycaprolactone, glycolide-lactide copolymer, caprolactone-lactide copolymer, and caprolactone-glycolic acid copolymer.

[0012] Furthermore, the matrix material is polylactic acid.

[0013] Furthermore, the process of modifying the matrix material with lysine or polylysine is as follows: first, a group that can react with lysine is grafted onto the surface of the matrix material using a chain extender, and then reacted with polylysine (exemplarily, ε-polylysine hydrochloride) or lysine, so that the polylysine or lysine is grafted onto the matrix material.

[0014] Furthermore, the chain extender is malic acid, glutamic acid, or maleic anhydride.

[0015] Furthermore, the excipient is a combination of one or more of the following: natural polysaccharides, sodium alginate, chitosan, hyaluronic acid, and chondroitin sulfate.

[0016] Furthermore, the emulsifier is water-soluble cellulose, specifically any water-soluble cellulose that can be used in medical implant materials. The specific type is not an innovation of this invention and will not be elaborated here. For example, it can be sodium carboxymethyl cellulose, 9004-32-4, Aladdin.

[0017] Furthermore, the bone wax comprises the following raw material components in parts by weight: 50-90 parts of lysine or polylysine modified matrix material, 5-10 parts of excipients, and 1-5 parts of emulsifier.

[0018] On the other hand, the present invention provides a method for preparing antibacterial absorbable bone wax, wherein lysine or polylysine modified matrix material, auxiliary materials and emulsifier are mixed in a solvent system and dried to obtain the finished bone wax product.

[0019] Furthermore, the solvent system is at least one of chloroform and deionized water.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] (1) Hemostatic effect: The present invention has a good hemostatic effect. The reasons are: firstly, the excipients have a good water absorption effect, which can concentrate the blood and cause platelets, red blood cells, clotting proteins, etc. to aggregate, thereby promoting hemostasis; secondly, lysine is positively charged, and it will combine with negatively charged red blood cells and platelets that easily adsorb charged substances in the blood, thereby promoting hemostasis.

[0022] (2) Degradation effect: The present invention can be completely degraded in 3-6 months, perfectly matching the speed of bone regeneration, and has ideal bone wax degradation characteristics.

[0023] (3) Osteogenic effect: The present invention has a better osteogenic effect than traditional bone wax and novel bone wax that does not contain bioceramics and mineralized polymers such as hydroxyapatite. The reason is that lysine carries a positive charge and can capture phosphate ions in body fluids during the osteogenic process, thereby improving the efficiency of the osteogenic process.

[0024] (4) Antibacterial effect: This invention has a good antibacterial effect and can effectively inhibit the growth of Staphylococcus aureus. The reason is that the lysine molecule contains a free amino group, which can be protonated to form a positive charge under physiological pH conditions. This positively charged property allows lysine to interact with the negatively charged regions on the microbial cell membrane, interfering with the normal function of the cell membrane. Attached Figure Description

[0025] Figure 1 The images show the osteogenesis test results of the bone wax of the present invention and the comparative bone wax, wherein A is the bone wax of Example 1, B is the bone wax of Example 2, C is the conventional bone wax of Comparative Example 1, and D is the bone wax of Comparative Example 2.

[0026] Figure 2 The results of antibacterial tests of bone wax and comparative bone wax of the present invention are shown. In this invention, A is bone wax of Example 1, B is bone wax of Example 2, C is conventional bone wax of Comparative Example 1, and D is bone wax of Comparative Example 2. Detailed Implementation

[0027] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0028] In the following embodiments, the polylactic acid used has the CAS number 26023-30-3, and the emulsifier used is sodium carboxymethyl cellulose, 9004-32-4, Aladdin.

[0029] Unless otherwise specified, all other raw materials or processing techniques are commercially available materials or conventional processing techniques in the field.

[0030] Example 1

[0031] Preparation method of polylysine-modified polylactic acid: 50g of lactic acid was added to a 100mL three-necked flask, connected to a mechanical stirrer and distillation apparatus, and connected to a double-row tube. After purging with nitrogen three times, the mechanical stirrer was turned on (100rpm), and the reaction was carried out at 10kPa and 150℃ for 3h, followed by a reaction at 1kPa and 165±10℃ for 1.5h to obtain a lactic acid oligomer, which is a yellow viscous substance. Then, 5g of glutamic acid was added, and the reaction was carried out at 100Pa and 165±10℃ for 1.5h. Then, heating was stopped, vacuum was turned off, and stirring was stopped. After the temperature dropped to room temperature, the product was dissolved in 200 mL of chloroform and then added dropwise to ethanol with stirring to settle. After filtration, the filter cake was washed three times with ethanol and then dried in a vacuum drying oven at 45°C until constant weight. The obtained copolymer was then immersed in a 0.1 mol / L sodium hydroxide solution for 2 minutes, then removed and immersed in a 0.3 mol / L ε-polylysine hydrochloride aqueous solution for 2 hours. After immersion, it was first air-dried and then dried in a vacuum drying oven at 45°C until constant weight. The weight-average molecular weight of the obtained copolymer (i.e., polylysine-modified polylactic acid) was approximately 12,000-15,000.

[0032] Bone wax preparation method: First, polylysine-modified polylactic acid (PLA) with a solid content of 60 wt% is dissolved in chloroform, sodium alginate with a solid content of 10 wt% is dissolved in deionized water, and water-soluble cellulose with a solid content of 10 wt% is dissolved in deionized water. Then, the three solutions are mixed at 40°C by stirring, with a mass ratio of 85:10:5 for polylysine-modified PLA, sodium alginate, and water-soluble cellulose. After no obvious liquid residue remains, it is freeze-dried for later use.

[0033] Example 2

[0034] Lysine-modified polylactic acid: 50g polylactic acid, 1g maleic anhydride, and 0.2g benzoyl peroxide were added to a 100mL three-necked flask. A mechanical stirrer was connected, and a double-row tube was attached. After purging with nitrogen three times, the mechanical stirrer was turned on (100rpm). The reaction was carried out at atmospheric pressure and 175±10℃ for 1h. Then, 1.8g L-lysine was added, and the reaction was continued at atmospheric pressure and 175±10℃ for 2h. Heating was then stopped, the vacuum was turned off, and stirring was stopped. After the temperature dropped to room temperature, the product was dissolved in 200mL chloroform and then added dropwise to ethanol with stirring to settle. The mixture was filtered, and the filter cake was washed three times with ethanol. The filter cake was then dried in a vacuum drying oven at 45℃ until constant weight. The weight-average molecular weight of the obtained copolymer was 11700, and the mass ratio of lysine to polylactic acid was approximately 1:100.

[0035] Bone wax preparation method: First, lysine-modified polylactic acid (PLA) with a solid content of 50 wt% is dissolved in chloroform, sodium alginate with a solid content of 10 wt% is dissolved in deionized water, and water-soluble cellulose with a solid content of 10 wt% is dissolved in deionized water. Then, the three solutions are mixed at 40°C by stirring, with a mass ratio of lysine-modified PLA, sodium alginate, and water-soluble cellulose of 85:10:5. After no obvious liquid residue remains, it is freeze-dried for later use.

[0036] Comparative Example 1:

[0037] Traditional bone wax preparation method: Prepared according to the formula in Chinese patent CN1172725C, which was approved by the SFDA in 2003. The specific procedure is as follows: Weigh the above components according to the ratio of 65 parts beeswax, 20 parts liquid paraffin, and 15 parts lanolin, and then mix them. Add 5 parts activated charcoal to the mixture at 80-90℃ and mix thoroughly. Then filter through filter paper to remove the activated charcoal, filtering 3-6 times until no black components remain in the mixture. Then pour the mixture into 90℃ hot water and slowly cool to form the wax. After forming, remove the bone wax from the aqueous solution and remove surface moisture for later use.

[0038] Comparative Example 2:

[0039] Preparation method of lysine-free or polylysine-modified polylactic acid absorbable bone wax: First, dissolve polylactic acid (50 wt% solids) in chloroform, sodium alginate (10 wt% solids) in deionized water, and water-soluble cellulose (10 wt% solids) in deionized water. Then, mix the three solutions at 40°C with stirring, using a mass ratio of polylactic acid, sodium alginate, and water-soluble cellulose of 85:10:5. After no obvious liquid residue remains, freeze-dry for later use.

[0040] Example 3

[0041] Hemostatic performance test: Examples 1 and 2, and Comparative Examples 1 and 2 were evenly applied to the drilled cancellous bone defects in pigs, ensuring complete sealing of the defects. After standing for 10 minutes, the pig cancellous bone was immersed in water for 5 minutes before being removed and the effect observed. The results showed that Examples 1 and 2, and Comparative Examples 1 and 2 all adhered well to the cancellous bone defects, and after immersion in water, the four types of bone wax remained intact, sealing the defects without falling off. This indicates that all four bone wax products have good hemostatic effects.

[0042] Example 4

[0043] Degradation performance test: Examples 1 and 2, and Comparative Examples 1 and 2 were immersed in phosphate buffer (pH = 7.4) at a ratio of bone wax mass (g): solution volume (mL) of 1:30, and the experiment was carried out at 37°C with shaking at 200 rpm. The results are as follows: the bone wax prepared in Example 1 was completely degraded after immersion in phosphate buffer for 12 weeks; the bone wax prepared in Example 2 was completely degraded after immersion in phosphate buffer for 24 weeks; the bone wax prepared in Comparative Example 2 was approximately 50% degraded after immersion in phosphate buffer for 24 weeks; and Comparative Example 1 showed almost no degradation. The human bone defect repair cycle is 12 months, and the degradation rate of Examples 1 and 2 matches the bone growth rate. Therefore, Examples 1 and 2 have good and suitable degradation performance.

[0044] Example 5

[0045] Osteogenic performance test: Examples 1 and 2, and Comparative Examples 1 and 2 were immersed in 5 times the volume of simulated body fluid (Na₂O₃) at a bone wax mass (g) : solution volume (mL) ratio of 1:30. + 213mM, K + 7.5mM, Mg 2+ 2.25mM, Ca 2+ 3.75mM, Cl-: 154.5mM, HCO3- - 40.5mM, HPO4 2- 1.5mM, SO4 2- The sample was placed in a solution of 0.75 mM (pH = 7.4) at 37°C for 7 days. The results are attached. Figure 1 As shown, both Examples 1 and 2 exhibit significant apatite deposition on their surfaces, while Comparative Example 1 shows only a small amount of apatite deposition. The apatite deposition on Comparative Example 2 is significantly less than in Examples 1 and 2 but more than in Comparative Example 1. This may be because the acidic nature of polylactic acid degradation products leads to apatite degradation. These results indicate that the introduction of lysine promotes bone wax osteogenic formation. Example 1 demonstrates better osteogenic effects than Example 2 because it contains a higher lysine content, which enhances its ability to promote apatite deposition through electroadsorption.

[0046] Example 6

[0047] Antibacterial performance test: Examples 1 and 2, and Comparative Examples 1 and 2 were immersed in phosphate buffer (pH = 7.4) at a bone wax mass (g): solution volume (mL) ratio of 1:30. After shaking at 200 rpm for one day at 37°C, the supernatant was collected for later use. The supernatant of each of the four materials was mixed with Staphylococcus aureus suspension, and the four bacterial suspensions were then incubated at 37°C for 48 hours. Colony formation was then observed. The results are attached. Figure 2 As shown, compared with the control group, Examples 1 and 2 inhibited the growth of Staphylococcus aureus by more than 50%, and there was no significant difference in the antibacterial performance between Examples 1 and 2. This result can be explained by grafting the amino group (NH2) of lysine into the PLA structure. Publicly available research indicates that polymers with suspended lysine amino groups possess antibacterial properties. The amino group in their structure is protonated in aqueous media and interacts with the negatively charged membrane of microbial cells. This interaction can interfere with membrane properties in two ways: firstly, by altering membrane permeability, leading to an internal osmotic pressure imbalance and inhibiting microbial growth; and secondly, by hydrolyzing the peptidoglycan of the microbial cell wall, resulting in the leakage of intracellular electrolytes such as potassium ions, proteins, nucleic acids, glucose, and other components essential for cellular function. The Staphylococcus aureus inhibitory effect demonstrates that polymers with exposed lysine amino groups exhibit high antibacterial activity against Gram-positive bacteria.

[0048] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. An antibacterial absorbable bone wax, characterized in that, The raw material components include the following parts by weight: 20-90 parts of lysine or polylysine modified matrix material, 2-20 parts of auxiliary materials, and 0.5-10 parts of emulsifier.

2. The antibacterial absorbable bone wax according to claim 1, characterized in that, The matrix material is one or more of polylactic acid, polyglycolic acid, polycaprolactone, glycolide-lactide copolymer, caprolactone-lactide copolymer, and caprolactone-glycolic acid copolymer.

3. The antibacterial absorbable bone wax according to claim 1, characterized in that, The matrix material is polylactic acid.

4. The antibacterial absorbable bone wax according to claim 1, characterized in that, The process of modifying the matrix material with lysine or polylysine is as follows: first, a group that can react with lysine is grafted onto the surface of the matrix material using a chain extender, and then reacted with polylysine or lysine, so that the polylysine or lysine is grafted onto the matrix material.

5. The antibacterial absorbable bone wax according to claim 4, characterized in that, The chain extender is malic acid, glutamic acid, or maleic anhydride.

6. The antibacterial absorbable bone wax according to claim 1, characterized in that, The auxiliary material is a combination of one or more of the following: natural polysaccharides, sodium alginate, chitosan, hyaluronic acid, and chondroitin sulfate.

7. The antibacterial absorbable bone wax according to claim 1, characterized in that, The emulsifier is water-soluble cellulose.

8. The antibacterial absorbable bone wax according to claim 1, characterized in that, It comprises the following raw material components in parts by weight: 50-90 parts of lysine or polylysine modified matrix material, 5-10 parts of auxiliary materials, and 1-5 parts of emulsifier.

9. The method for preparing antibacterial absorbable bone wax according to any one of claims 1-8, characterized in that, In a solvent system, lysine or polylysine-modified matrix materials, auxiliary materials, and emulsifiers are mixed and dried to obtain the finished bone wax product.

10. The method for preparing antibacterial absorbable bone wax according to claim 9, characterized in that, The solvent system is at least one of chloroform and deionized water.

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