Tissue filler for injection and preparation method thereof

Abstract

The invention provides a tissue filler for injection and a preparation method thereof, and belongs to the technical field of beauty product manufacturing. The tissue filler for injection is a colloidal solution, the colloidal solution comprises amphiphilic block copolymer microspheres, a solubilizer and water, the solubilizer is a polyhydroxy compound, the tissue filler for injection is a colloidal solution and has the advantages that a needle is not prone to being blocked during application, and the tissue filler can be uniformly dispersed after injection; the colloidal solution also has the advantage of good stability.

Description

Technical Field

[0001] This application relates to the field of cosmetic product manufacturing technology, and more specifically, to an injectable tissue filler and its preparation method. Background Technology

[0002] With the improvement of living standards, people are paying more and more attention to the pursuit of external beauty. For example, when faced with natural skin laxity and wrinkles, people use cosmetic surgery and injectable cosmetic products to improve their skin condition. Among these, injectable cosmetic products (usually mainly composed of injectable tissue fillers) are widely recognized in the beauty field due to their advantages of good cosmetic effects, minimal pain during treatment, and ease of acceptance. Currently, tissue fillers in injectable cosmetic products are mainly divided into two categories: biodegradable and non-biodegradable. Biodegradable materials mainly include first-generation collagen and second-generation hyaluronic acid. However, these types of materials have the problem of a relatively short degradation period in the body.

[0003] Based on this, engineers have proposed third-generation biodegradable materials with longer degradation cycles, mainly including polylactic acid or polycaprolactone and their block copolymers. However, third-generation biodegradable materials are usually prepared as gel products, such as a polycaprolactone microsphere gel disclosed in patent CN11596259A, and a polycaprolactone microsphere containing hyaluronic acid and collagen disclosed in patent CN14904049A. However, gel-type injectable tissue fillers have some common problems, such as the microsphere particle size in the gel system is usually in the micrometer range and it is difficult to disperse uniformly in the gel system. In addition, the viscosity of gel-type materials is relatively high, which leads to problems such as easy needle blockage during injection and uneven dispersion after injection. Therefore, it is urgent to solve the problems of easy needle blockage during injection and uneven dispersion after injection of third-generation biodegradable materials. Summary of the Invention

[0004] The purpose of this application is to provide an injectable tissue filler and its preparation method. The injectable tissue filler is a colloidal solution, which has the advantages of not easily clogging the needle and being able to disperse evenly after injection. In addition, the colloidal solution also has the advantage of good stability.

[0005] The embodiments of this application are implemented as follows: In a first aspect, embodiments of this application provide an injectable tissue filler, which is a colloidal solution comprising amphiphilic block copolymer microspheres, a solubilizer, and water, wherein the solubilizer is a polyhydroxy compound.

[0006] In the above technical solution, the injectable tissue filler containing amphiphilic block copolymer microspheres is a colloidal solution. Colloidal solutions have numerous characteristics: firstly, the microspheres in the colloidal solution can reach the nanometer scale and have good particle size uniformity; secondly, the viscosity of the colloidal solution is low; and thirdly, the amphiphilic block copolymer microspheres have good dispersibility in the colloidal solution. These numerous characteristics make the colloidal solution-type injectable tissue filler less likely to clog needles, less painful, and have good microsphere dispersion after injection. Furthermore, the colloidal solution also contains the aforementioned solubilizers. The addition of these solubilizers makes the colloidal solution have good stability (specifically, the microsphere particle size and particle size uniformity are relatively stable over a long period of time), thus enabling it to exert a long-lasting filling effect and have high safety after being injected into the tissue. In addition, it is also convenient for storage and transportation.

[0007] In some alternative embodiments, the polyhydroxy compound is selected from at least one of polyethylene glycol and glycerol.

[0008] In the above technical solution, the above-mentioned polyhydroxy compounds are selected as solubilizers, which can be well adapted to the amphiphilic block copolymer microspheres in the colloidal solution, thereby effectively improving the stability of the colloidal solution.

[0009] In some alternative embodiments, the polyhydroxy compound is selected from polyethylene glycol, and the weight-average molecular weight of polyethylene glycol is 200 to 2000.

[0010] In the above technical solution, polyethylene glycol is selected as a solubilizer and its weight-average molecular weight is limited to the above range. This solubilizer can better adapt to the amphiphilic block copolymer microspheres in the colloidal solution, thereby more effectively improving the stability of the colloidal solution.

[0011] In some alternative embodiments, the solubilizer accounts for 1 to 10% by mass in the tissue filler; or / and the amphiphilic block copolymer microspheres account for 10 to 50% by mass.

[0012] In the above technical solution, the mass ratio of solubilizer in the tissue filler is limited to the above range so that the tissue filler has a suitable amount of solubilizer, thereby making the colloidal solution have suitable stability; in addition, the mass ratio of amphiphilic block copolymer microspheres in the tissue filler is limited to the above range so that the tissue filler has a suitable amount of amphiphilic block copolymer microspheres, thereby making the tissue filler have a suitable tissue filling effect, and at the same time, it can also make the colloidal solution have a suitable viscosity, thus facilitating injection with a needle.

[0013] In some alternative embodiments, the average particle size of the amphiphilic block copolymer microspheres is 100–300 nm.

[0014] In the above technical solution, the amphiphilic block copolymer microspheres have a smaller particle size, which has advantages such as less thrust, less difficulty in injecting with needles, and less pain when using needles for injection.

[0015] In some alternative embodiments, the amphiphilic block copolymer microspheres contain a diblock amphiphilic block copolymer; and / or the hydrophilic polymer is selected from at least one of methoxy polyethylene glycol, dihydroxy polyethylene glycol, monoalkoxy polyethylene glycol, and monoacyl polyethylene glycol, and the hydrophobic polymer is selected from at least one of polycaprolactone, polylactic acid, polytrimethyl carbonate, and polyhydroxybutyrate.

[0016] In the above technical solution, the amphiphilic block copolymer is a diblock amphiphilic block copolymer, which has the advantage of good sphericity; in addition, the hydrophilic polymer material and the hydrophobic polymer material can be freely combined according to the above selection, which has a lot of possible implementation schemes, thereby facilitating the promotion and application of the technical solution provided in the embodiments of this application; at the same time, the above-mentioned materials also have advantages such as good biocompatibility and long duration of tissue filling effect.

[0017] In some alternative embodiments, the tissue filler also includes a pH adjuster selected from at least one of a phosphate system, a citrate-citrate system, and an acetate-acetate system.

[0018] In the above-mentioned technical solution, the tissue filler also includes the aforementioned pH adjuster, which can make the pH and osmotic pressure of the tissue filler more consistent with the corresponding parameters in the tissue, thereby helping to reduce the inflammatory response caused by the injection of the tissue filler.

[0019] In some alternative implementations, the pH adjuster has a molar concentration of 10–50 mmol / L in the tissue filler.

[0020] In the above technical solution, the molar concentration of the pH adjuster in the tissue filler is limited to the above range so that the tissue filler contains a suitable amount of pH adjuster, thereby ensuring that the pH and osmotic pressure of the tissue filler are always maintained within a suitable range.

[0021] In a second aspect, embodiments of this application provide a method for preparing an injectable tissue filler as provided in the first aspect embodiment, comprising the following steps: mixing a solubilizer and water, wherein the solubilizer is a polyhydroxy compound, to obtain an aqueous solution; providing an amphiphilic block copolymer, mixing the amphiphilic block copolymer and the aqueous solution to obtain a mixed solution; and stirring the mixed solution at a preset temperature, wherein the preset temperature is not less than the melting point of the amphiphilic block copolymer and not higher than the boiling point of water, so that the amphiphilic block copolymer self-assembles to form amphiphilic block copolymer microspheres, thereby obtaining an injectable tissue filler.

[0022] In the above technical solution, the injectable tissue filler provided in the first aspect embodiment can be prepared according to the above process. Specifically, a mixed solution containing a solubilizer and an amphiphilic block copolymer is stirred at a preset temperature. The preset temperature is not lower than the melting point of the amphiphilic block copolymer and not higher than the boiling point of water. Under the combined action of the solubilizer and the heating conditions, the amphiphilic block copolymer can be rapidly and thoroughly self-assembled to form amphiphilic block copolymer microspheres, thereby obtaining a colloidal solution type injectable tissue filler.

[0023] In some alternative embodiments, the amphiphilic block copolymer is a diblock amphiphilic block copolymer in which the mass ratio of the hydrophilic polymer to the hydrophobic polymer is 1:(1~10); or / and the weight average molecular weight of the hydrophilic polymer is 500~20000 and the weight average molecular weight of the hydrophobic polymer is 500~200000.

[0024] In the above technical solution, the amphiphilic block copolymer is a diblock amphiphilic block copolymer, which facilitates the formation of microspheres by self-assembly of the block copolymer. Furthermore, the mass ratio of the hydrophilic polymer and the hydrophobic polymer and their respective weight-average molecular weights are limited to the above range, which facilitates the rapid and relatively thorough formation of amphiphilic block copolymer microspheres by self-assembly of the amphiphilic block copolymer.

[0025] In some alternative embodiments, in the amphiphilic block copolymer, the hydrophilic polymer is selected from at least one of methoxy polyethylene glycol, dihydroxy polyethylene glycol, monoalkoxy polyethylene glycol, and monoacyl polyethylene glycol, and the hydrophobic polymer is selected from at least one of polycaprolactone, polylactic acid, polytrimethyl carbonate, and polyhydroxybutyrate; and in the step of stirring the mixed solution at a preset temperature, the preset temperature is 65~80°C.

[0026] In the above technical solution, when the two polymer materials in the amphiphilic block copolymer are selected from the above types, the preset temperature is limited to the above range so that the corresponding amphiphilic block copolymer can form amphiphilic block copolymer microspheres relatively quickly and thoroughly through self-assembly.

[0027] In some alternative embodiments, the aqueous solution is further mixed with a pH adjuster, wherein the pH adjuster is selected from at least one of a phosphate system, a citrate-citrate system, and an acetate-acetate system.

[0028] In the above technical solution, the aqueous solution also contains the aforementioned pH adjusters, which enable the pH and osmotic pressure of the initially prepared tissue filler to be close to the corresponding parameters in the tissue, and also enable the pH and osmotic pressure of the tissue filler to be maintained within a suitable range for a longer period of time, which helps to reduce the foreign body sensation caused by the injection of the tissue filler.

[0029] In some alternative implementations, the molar concentration of the pH adjuster in the aqueous solution is 10–50 mmol / L.

[0030] In the above technical solution, the molar concentration of the pH adjuster in the aqueous solution is limited to the above range so that the pH and osmotic pressure of the initially prepared tissue filler are close to the corresponding parameters in the tissue, and the pH and osmotic pressure of the tissue filler can be maintained within a suitable range for a longer period of time. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 A process flow diagram of a method for preparing an injectable tissue filler provided in this application; Figure 2 This is an electron microscope image of the injectable tissue filler of Example 1 of this application; Figure 3 A photograph of a rat after injection of PBS buffer, as provided in this application. Figure 4 A photograph of a rat after injection of the sample from Example 1 provided in this application; Figure 5 A photograph of the rats after injection of the comparative example 1 sample provided in this application; Figure 6 Tissue staining image of rats after injection of PBS buffer as provided in this application; Figure 7 Tissue staining image of rats after injection of the sample provided in Example 1 of this application; Figure 8 The distribution diagram of collagen in rat tissue after injection of PBS buffer provided in this application; Figure 9 Distribution diagram of collagen in rat tissue after injection of the sample provided in Example 1 of this application. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0034] It should be noted that the terms "and / or" in this application, such as "feature 1 and / or feature 2", all refer to the three cases of "feature 1" alone, "feature 2" alone, and "feature 1" plus "feature 2".

[0035] In addition, in the description of this application, unless otherwise stated, "one or more" means two or more; the range of "numerical value a to numerical value b" includes the two endpoints "a" and "b"; and "unit of measurement" in "numerical value a to numerical value b + unit of measurement" represents the "unit of measurement" of both "numerical value a" and "numerical value b".

[0036] The following is a detailed description of an injectable tissue filler and its preparation method according to an embodiment of this application.

[0037] In a first aspect, embodiments of this application provide an injectable tissue filler, which is a colloidal solution comprising amphiphilic block copolymer microspheres, a solubilizer, and water, wherein the solubilizer is a polyhydroxy compound.

[0038] In this application, the injectable tissue filler containing amphiphilic block copolymer microspheres is a colloidal solution. Colloidal solutions have numerous characteristics: firstly, the microspheres in the colloidal solution can reach nanometer-scale particle size and have good particle size uniformity; secondly, the colloidal solution has low viscosity; and thirdly, the amphiphilic block copolymer microspheres have good dispersibility in the colloidal solution. These numerous characteristics make the colloidal solution-type injectable tissue filler less likely to clog needles, less painful, and have good microsphere dispersion after injection (lower foreign body sensation and good safety). Furthermore, the colloidal solution also contains the aforementioned solubilizers. The addition of these solubilizers makes the colloidal solution have good stability (specifically, the microsphere particle size and particle size uniformity are relatively stable over a long period of time, i.e., the microspheres are not prone to aggregation or rapid degradation), thereby enabling it to exert a long-lasting filling effect and have high safety after injection into the tissue. In addition, it is also convenient for storage and transportation.

[0039] As an example, the polyhydroxy compound is selected from at least one of polyethylene glycol and glycerol.

[0040] In this embodiment, the aforementioned polyhydroxy compounds are selected as solubilizers, which can be well adapted to the amphiphilic block copolymer microspheres in the colloidal solution, thereby effectively improving the stability of the colloidal solution.

[0041] As an example, the polyhydroxy compound is selected from polyethylene glycol, and the polyethylene glycol has a weight-average molecular weight of 200 to 2000, for example, but not limited to any point value or range between any two of the weight-average molecular weights of 200, 400, 600, 800, 1000, 1200, 1400, 1600, 1800 and 2000.

[0042] In this embodiment, polyethylene glycol is selected as the solubilizer and its weight-average molecular weight is limited to the above-mentioned range. This solubilizer can better adapt to the amphiphilic block copolymer microspheres in the colloidal solution, thereby more effectively improving the stability of the colloidal solution.

[0043] As an example, in tissue fillers, the mass percentage of solubilizer is 1 to 10%, such as, but not limited to, any one of the mass percentages of 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, and 10%, or any range between two.

[0044] In this embodiment, the mass ratio of solubilizer in the tissue filler is limited to the above-mentioned range so that the tissue filler contains a suitable amount of solubilizer, thereby making the colloidal solution have suitable stability.

[0045] As an example, the amphiphilic block copolymer microspheres in the tissue filler account for 10-50% by mass, for example, but not limited to any one of 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% and 50% by mass or any range between two.

[0046] In this embodiment, the mass percentage of amphiphilic block copolymer microspheres in the tissue filler is limited to the above-mentioned range so that the tissue filler contains a suitable amount of amphiphilic block copolymer microspheres, thereby enabling the tissue filler to have a suitable tissue filling effect. At the same time, it also enables the colloidal solution to have a suitable viscosity, thus facilitating injection using a needle.

[0047] As an example, the average particle size of the amphiphilic block copolymer microspheres is 100 to 300 nm, for example, but not limited to, any one of 100 nm, 150 nm, 200 nm, 250 nm and 300 nm or any range between two.

[0048] In this embodiment, the amphiphilic block copolymer microspheres have a smaller particle size, which has advantages such as less thrust, less difficulty in injecting with a needle, and less pain when using a needle for injection.

[0049] In some alternative embodiments, the amphiphilic block copolymer microspheres contain a diblock (i.e., AB-type) amphiphilic block copolymer.

[0050] In this embodiment, the amphiphilic block copolymer is a diblock amphiphilic block copolymer, which has the advantage of good sphericity.

[0051] As an example, the hydrophilic polymer is selected from at least one of methoxy polyethylene glycol, dihydroxy polyethylene glycol, monoalkoxy polyethylene glycol, and monoacyl polyethylene glycol, and the hydrophobic polymer is selected from at least one of polycaprolactone, polylactic acid, polytrimethyl carbonate, and polyhydroxybutyrate.

[0052] In this embodiment, the hydrophilic polymer material and the hydrophobic polymer material can be freely combined according to the above selection, which has many possible implementation schemes, thereby facilitating the promotion and application of the technical solutions provided in the embodiments of this application; at the same time, the above-mentioned materials also have advantages such as good biocompatibility and long-lasting tissue filling effect.

[0053] As an example, the tissue filler also includes a pH adjuster, wherein the pH adjuster is selected from at least one of a phosphate system, a citrate-citrate system, and an acetate-acetate system.

[0054] In this embodiment, the tissue filler also includes the aforementioned type of pH adjuster, which enables the pH and osmotic pressure of the tissue filler to be more consistent with the corresponding parameters in the tissue, thereby helping to reduce the inflammatory response caused by the injection of the tissue filler.

[0055] It should be noted that the pH adjuster mentioned above is the raw material component for preparing various system buffers, and the specific raw material components in various systems are not limited and can be set according to the conventional selection in this field.

[0056] As an example, phosphate systems include disodium hydrogen phosphate and potassium dihydrogen phosphate, citric acid-citrate systems include citric acid and sodium citrate, and acetic acid-acetate systems include acetic acid and sodium acetate.

[0057] As an example, in tissue fillers, the molar concentration of the pH adjuster is 10 to 50 mmol / L, for example, but not limited to any one of the molar concentrations of 10 mmol / L, 20 mmol / L, 30 mmol / L, 40 mmol / L, and 50 mmol / L, or any range between two of them.

[0058] In this embodiment, the molar concentration of the pH adjuster in the tissue filler is limited to the above-mentioned range so that the tissue filler contains a suitable amount of pH adjuster, thereby ensuring that the pH and osmotic pressure of the tissue filler are always maintained within a suitable range.

[0059] It should be noted that functional components in injectable tissue fillers that are not specifically described or limited can be selected and set in accordance with conventional practices in the field.

[0060] In a second aspect, embodiments of this application provide a method for preparing an injectable tissue filler as provided in the first aspect embodiment, comprising the following steps: mixing a solubilizer and water, wherein the solubilizer is a polyhydroxy compound, to obtain an aqueous solution; providing an amphiphilic block copolymer, mixing the amphiphilic block copolymer and the aqueous solution to obtain a mixed solution; and stirring the mixed solution at a preset temperature, wherein the preset temperature is not less than the melting point of the amphiphilic block copolymer and not higher than the boiling point of water, so that the amphiphilic block copolymer self-assembles to form amphiphilic block copolymer microspheres, thereby obtaining an injectable tissue filler.

[0061] In this application, the injectable tissue filler provided in the first aspect embodiment can be prepared according to the above process. Specifically, a mixed solution containing a solubilizer and an amphiphilic block copolymer is stirred at a preset temperature. The preset temperature is not lower than the melting point of the amphiphilic block copolymer and not higher than the boiling point of water. Under the combined action of the solubilizer and the heating conditions, the amphiphilic block copolymer can be rapidly and thoroughly self-assembled to form amphiphilic block copolymer microspheres, thereby obtaining a colloidal solution type injectable tissue filler.

[0062] It should be noted that, in addition to helping the amphiphilic block copolymers to form amphiphilic block copolymer microspheres through self-assembly during the preparation process, the addition of the above-mentioned solubilizers also ensures that the prepared injectable tissue filler still has a stable solubilizer because it does not participate in the reaction during the entire preparation process. This also gives the injectable tissue filler excellent stability.

[0063] As an example, an amphiphilic block copolymer is a diblock amphiphilic block copolymer.

[0064] In this embodiment, the amphiphilic block copolymer is a diblock amphiphilic block copolymer, which facilitates the self-assembly of the block copolymer into microspheres.

[0065] As an example, in an amphiphilic block copolymer, the mass ratio of the hydrophilic polymer to the hydrophobic polymer is 1:(1~10), for example, but not limited to any one of the mass ratios of 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 and 1:10, or any range between the two.

[0066] As an example, the weight-average molecular weight of the hydrophilic polymer is 500 to 20,000, for example, but not limited to any one of the weight-average molecular weights of 500, 1,000, 5,000, 10,000, 15,000, and 20,000, or any range between the two; the weight-average molecular weight of the hydrophobic polymer is 500 to 200,000, for example, but not limited to any one of the weight-average molecular weights of 500, 1,000, 5,000, 10,000, 20,000, 50,000, 100,000, 150,000, and 200,000, or any range between the two.

[0067] In this embodiment, the mass ratio of the hydrophilic polymer and the hydrophobic polymer and their respective weight-average molecular weights are limited to the above-mentioned ranges, which facilitates the rapid and relatively thorough self-assembly of the amphiphilic block copolymer to form amphiphilic block copolymer microspheres.

[0068] As an example, in the amphiphilic block copolymer, the hydrophilic polymer is selected from at least one of methoxy polyethylene glycol, dihydroxy polyethylene glycol, monoalkoxy polyethylene glycol, and monoacyl polyethylene glycol, and the hydrophobic polymer is selected from at least one of polycaprolactone, polylactic acid, polytrimethyl carbonate, and polyhydroxybutyrate; and in the step of stirring the mixed solution at a preset temperature, the preset temperature is 65~80°C, for example, but not limited to any one of 65°C, 70°C, 75°C, and 80°C, or any range between two of them.

[0069] In this embodiment, when the two polymer materials in the amphiphilic block copolymer are selected from the above types, the preset temperature is limited to the above range so that the corresponding amphiphilic block copolymer can form amphiphilic block copolymer microspheres relatively quickly and thoroughly through self-assembly.

[0070] It should be noted that in the step of providing amphiphilic block copolymers, the amphiphilic block copolymers can be purchased directly according to actual specifications, or they can be prepared by ourselves according to actual specifications.

[0071] To better understand the technical solution, an example is provided here using the self-prepared (MPEG5000-PCL20000) amphiphilic block copolymer. The preparation method of the amphiphilic block copolymer includes the following steps: Inert gas was introduced into the reactor to remove air. Then, 15 g of stannous octoate (catalyst) and 1.00 kg of polyethylene glycol monomethyl ether 5000 (MPEG5000) were added to the reactor containing anhydrous toluene for azeotropic dehydration. Then, 3.5 kg of ε-caprolactone (ε-CL) was added to the reactor and mixed to obtain a mixture. The mixture was then reacted at a constant temperature of 120-140℃ for 48-72 h. After the reaction was completed, the obtained substance was dissolved in dichloromethane, precipitated with diethyl ether, and then washed successively with methanol and purified water. The solid precipitate was collected and dried to obtain the (MPEG5000-PCL20000) amphiphilic block copolymer.

[0072] It should be noted that in the above-mentioned amphiphilic block copolymer, the mass ratio of hydrophilic polymer to hydrophobic polymer can be controlled by the ratio of the amount of MPEG5000 added to the amount of ε-caprolactone added; the weight-average molecular weight of the hydrophobic polymer can be controlled by the ratio of the amount of catalyst added to the amount of ε-caprolactone added.

[0073] As an example, the aqueous solution also contains a pH adjuster selected from at least one of a phosphate system, a citrate-citrate system, and an acetate-acetate system.

[0074] In this embodiment, the aqueous solution also contains the aforementioned type of pH adjuster, which ensures that the pH and osmotic pressure of the initially prepared tissue filler are close to the corresponding parameters within the tissue. Furthermore, it allows the pH and osmotic pressure of the tissue filler to be maintained within a suitable range for a longer period, helping to reduce the foreign body sensation caused after tissue filler injection. As an example, the molar concentration of the pH adjuster in the aqueous solution is 10–50 mmol / L, for example, but not limited to, any one of 10 mmol / L, 20 mmol / L, 30 mmol / L, 40 mmol / L, and 50 mmol / L, or a range between any two.

[0075] In this embodiment, the molar concentration of the pH adjuster in the aqueous solution is limited to the above-mentioned range so that the pH and osmotic pressure of the initially prepared tissue filler are close to the corresponding parameters in the tissue, and the pH and osmotic pressure of the tissue filler can be maintained within a suitable range for a longer period of time.

[0076] It should be noted that, unless otherwise specified or limited, the process steps in the preparation of injectable tissue fillers can be performed in accordance with conventional methods in this field.

[0077] As an example, the step of stirring the mixed solution at a preset temperature includes: first stirring the mixed solution at a low speed (100~400 rpm) at the preset temperature to form a primary emulsion, and then stirring at a high speed (3000~5000 rpm) to achieve homogenization.

[0078] As an example, after the step of stirring the mixed solution at a preset temperature is completed, the process also includes filtering the formed colloidal solution, wherein the filter membrane has a pore size of 1 μm.

[0079] As an example, a process flow diagram of the preparation method of injectable tissue fillers can be exemplarily referred to. Figure 1 .

[0080] The features and performance of this application will be further described in detail below with reference to the embodiments.

[0081] Example 1 This application provides a method for preparing an injectable tissue filler, comprising the following steps: S1 Nitrogen gas was introduced into the reactor to purge air. Then, 15 g of stannous octoate (catalyst) and 1.00 kg of polyethylene glycol monomethyl ether 5000 (MPEG5000) were added to the reactor containing anhydrous toluene for azeotropic dehydration. Then, 3.5 kg of ε-caprolactone (ε-CL) was added to the reactor and mixed to obtain a mixture. The mixture was then reacted at 130 °C for 50 h. After the reaction was completed, the obtained substance was dissolved in dichloromethane, precipitated with diethyl ether, and then washed successively with methanol and purified water. The solid precipitate was collected and dried to obtain the (MPEG5000-PCL20000) amphiphilic block copolymer.

[0082] S2 Take 1.9734 g (0.013901 mol) of disodium hydrogen phosphate and 0.2245 g (0.001650 mol) of potassium dihydrogen phosphate, add water to dissolve to make 1000 ml, and obtain a phosphate buffer solution with a molar concentration of about 15.55 mmol / L. Then add 10 g of polyethylene glycol with a weight average molecular weight of 400 to it, stir well, and obtain an aqueous solution.

[0083] S3. 400 g of the (MPEG5000-PCL20000) amphiphilic block copolymer from S1 was added to an aqueous solution and mixed to obtain a mixed solution. The mixed solution was then stirred at 200 rpm at 80°C until the material was evenly dispersed. The stirring speed was then increased to 5000 rpm and stirred at high speed for 30 min. The mixture was then rapidly cooled to room temperature to obtain a colloidal solution. The cooled colloidal solution was then filtered through a flat plate filter with a pore size of 1 μm and filled into injectable tissue fillers.

[0084] Example 2 This application provides a method for preparing an injectable tissue filler, which differs from Example 1 only in that: S3 350 g of the (MPEG5000-PCL20000) amphiphilic block copolymer from S1 is added to an aqueous solution and mixed to obtain a mixed solution.

[0085] Example 3 This application provides a method for preparing an injectable tissue filler, comprising the following steps: S1 Nitrogen gas was introduced into the reactor to purge air. Then, 12 g of stannous octoate (catalyst) and 1.00 kg of polyethylene glycol monomethyl ether 5000 (MPEG5000) were added to the reactor containing anhydrous toluene for azeotropic dehydration. Then, 2.5 kg of ε-caprolactone (ε-CL) was added to the reactor and mixed to obtain a mixture. The mixture was then reacted at 130°C for 50 h. After the reaction was completed, the obtained substance was dissolved in dichloromethane, precipitated with diethyl ether, and then washed successively with methanol and purified water. The solid precipitate was collected and dried to obtain the (MPEG5000-PCL15000) amphiphilic block copolymer.

[0086] S2 Take 1.9734 g (0.013901 mol) of disodium hydrogen phosphate and 0.2245 g (0.001650 mol) of potassium dihydrogen phosphate, add water to dissolve to make 1000 ml, and obtain a phosphate buffer solution with a molar concentration of about 15.55 mmol / L. Then add 10 g of polyethylene glycol with a weight average molecular weight of 400 to it, stir well, and obtain an aqueous solution.

[0087] S3. 400 g of the (MPEG5000-PCL15000) amphiphilic block copolymer from S1 was added to an aqueous solution and mixed to obtain a mixed solution. The mixed solution was then stirred at 200 rpm at 80°C until the material was evenly dispersed. The stirring speed was then increased to 5000 rpm and stirred at high speed for 30 min. The mixture was then rapidly cooled to room temperature to obtain a colloidal solution. The cooled colloidal solution was then filtered through a flat plate filter with a pore size of 1 μm and filled into injectable tissue fillers.

[0088] Example 4 This application provides a method for preparing an injectable tissue filler, which differs from Example 1 only in that: in step S2, 10 g of polyethylene glycol with a weight average molecular weight of 400 is added to 1 L of water and stirred evenly to obtain an aqueous solution.

[0089] Comparative Example 1 This application provides a comparative example of a method for preparing an injectable tissue filler, comprising the following steps: S1 Nitrogen gas was introduced into the reactor to purge air. Then, 15 g of stannous octoate (catalyst) and 1.00 kg of polyethylene glycol monomethyl ether 5000 (MPEG5000) were added to the reactor containing anhydrous toluene for azeotropic dehydration. Then, 3.5 kg of ε-caprolactone (ε-CL) was added to the reactor and mixed to obtain a mixture. The mixture was then reacted at 130 °C for 50 h. After the reaction was completed, the obtained substance was dissolved in dichloromethane, precipitated with diethyl ether, and then washed successively with methanol and purified water. The solid precipitate was collected and dried to obtain the (MPEG5000-PCL20000) amphiphilic block copolymer.

[0090] S2. Take 10 g of the (MPEG5000-PCL20000) amphiphilic block copolymer from step S1 and dissolve it in 40 mL of dichloromethane. The completely dissolved polymer solution and a 0.1 wt% PVA aqueous solution are homogenized in a homogenizer at 5000 rpm for 10 min (with vacuuming to remove excess organic solvent while stirring). Then, the amphiphilic block polymer microspheres are obtained by low-temperature curing. The average particle size of the microspheres is 45.2 μm and the PDI is 1.885. Then, a 2 wt% carboxymethyl cellulose gel is prepared using PBS solution. Finally, 2.4 g of microspheres are added to 8 mL of gel and stirred evenly to obtain an injectable tissue filler.

[0091] Comparative Example 2 This application provides a comparative method for preparing an injectable tissue filler, which differs from Example 1 only in that polyethylene glycol is not added in step S1.

[0092] Test case (1) Electron microscopy test of injectable tissue fillers The test method involved using the tissue filler prepared in Example 1 as a sample, diluting it 100 times with deionized water, mixing it thoroughly, taking 10 μL of the diluted preparation, staining it with phosphomolybdic acid for 1 min, drying it, and then analyzing it using a transmission electron microscope.

[0093] See Figure 2 (Scale bar is 1 μm) It can be seen that, according to the preparation process provided in the embodiments of this application, the prepared colloidal solution contains microspheres with relatively uniform particle size and nanometer-scale particle size.

[0094] (2) Physicochemical properties testing of injectable tissue fillers The test method involved using the tissue fillers prepared in Examples 1-4 and Comparative Example 1 as samples. The average particle size, PDI, solution pH, osmotic pressure, shear viscosity, and microsphere content of each sample were then tested. The test results are summarized in Table 1.

[0095] Table 1

[0096] It should be noted that the osmotic pressure within a tissue is typically maintained in the range of 40 to 400 mOsm / kg. As shown in Table 1, the injectable tissue filler prepared in the embodiments of this application has a basically consistent osmotic pressure with that inside the tissue.

[0097] Referring to Table 1, the test results of Examples 1-4 and Comparative Example 1 show that the colloidal solution-type injectable tissue filler provided in this application has a smaller and more uniform particle size compared to the conventional gel solution-type injectable tissue filler. At the same time, the former also has a lower shear viscosity (the viscosity of the gel-type injectable tissue filler is too high to be measured).

[0098] (3) Pushing force test of tissue filler The test method involved using the tissue fillers prepared in Example 1 and Comparative Example 1 as samples, installing needles of different specifications, and pushing them with an electronic universal testing machine at a speed of 10 mm / min to test the average pushing force of the corresponding samples. The test results are then summarized in Table 2.

[0099] Table 2

[0100] As can be seen from Table 2, the colloidal solution-type injectable tissue filler provided in this application embodiment requires less extrusion force, can use smaller needles, and causes less pain during injection compared to conventional gel solution-type injectable tissue fillers.

[0101] (4) Stability test of injectable tissue fillers The test method involved using the injectable tissue fillers obtained from Examples 1, 4, and 2 as samples. The samples were then placed in a 40°C stability chamber for accelerated aging tests to examine their accelerated stability. The changes in pH, particle size, particle size uniformity, and osmotic pressure during the aging process were observed. The test results are then summarized in Table 3.

[0102] Table 3

[0103] Referring to Table 3, the test results of Example 1 and Comparative Example 2 show that the injectable tissue filler containing solubilizer has a smaller initial PDI than the one without solubilizer, indicating better particle size uniformity; and the particle size and particle size uniformity of the former are also relatively stable during the accelerated aging process, indicating that it has better stability.

[0104] The test results of Examples 1 and 4 show that injectable tissue fillers containing pH adjusters have a more stable pH during the accelerated aging process and an osmotic pressure closer to that of human tissue compared to those without pH adjusters, which helps to reduce the inflammatory response caused by tissue filler injection.

[0105] (5) Dispersibility test, tissue compatibility test, and collagen regeneration performance test of injectable tissue filler in tissue. Test Method: Five SD rats weighing 250 g and aged 6-8 weeks were selected as experimental animals. PBS phosphate buffer was set up as the control group, and Example 1 and Comparative Example 1 were set up as experimental groups. Two rats each received PBS buffer and Example 1, while one rat received Comparative Example 1. Injection Method: Four injection sites were made on the back of each rat, with 0.2 mL of sample injected subcutaneously at each site. During the experiment, the feeding environment was set at 24°C, 50% relative humidity, and 12 hours of light, with free access to food.

[0106] Two weeks after injection, one rat from each of the three samples was sacrificed to observe the diffusion of the injected samples.

[0107] See Figures 3-5 It can be seen that there were no obvious bumps on the skin of rats in the PBS solution group and the sample group of Example 1 two weeks after injection, indicating that the sample diffusion was good; while there were obvious bumps on the skin of rats injected with the sample group of Comparative Example 1, indicating that the colloidal solution type injectable tissue filler provided in this application has better dispersibility after injection compared with conventional gel solution type injectable tissue filler.

[0108] B. After 13 weeks of feeding, the PBS solution group and the Example 1 sample group were sacrificed. Skin tissue from the PBS solution group and the Example 1 sample group was obtained according to the injection marking sites, fixed in neutral 10% formalin solution, embedded in paraffin and solidified, and sections were prepared. Then, the sections were stained with hematoxylin and eosin to observe the tissue inflammatory response and thus determine tissue compatibility; the sections were stained with Sirius red to observe the distribution of collagen in the tissue and thus determine the effect of stimulating collagen regeneration.

[0109] See Figure 6 and Figure 7It was found that the epidermal structure of rats injected with PBS buffer and in the sample group of Example 1 was intact and clear, with a distinct stratum corneum, clearly visible subcutaneous fat layer and muscle layer, and neatly arranged adipocytes and muscle fibers with normal cell nuclei morphology. Meanwhile, the subcutaneous loose connective tissue structure in the PBS buffer group was normal, with no inflammatory cell infiltration or fibrous tissue hyperplasia, and no other obvious pathological changes were observed. In the rats injected with the sample group of Example 1, mild inflammatory cell infiltration, mainly macrophages, was observed in the subcutaneous fat layer, subcutaneous muscle layer, and subcutaneous loose connective tissue, with no other obvious pathological changes. This indicates that the colloidal solution-type injectable tissue filler provided in this application has good tissue compatibility and no obvious adverse inflammatory reactions.

[0110] See Figure 8 and Figure 9 It can be seen that the amount of type I and type III collagen in the rat skin tissue of the sample group injected in Example 1 was greater than that in the PBS buffer group, indicating that the colloidal solution-type injectable tissue filler provided in the example has a good collagen stimulation effect.

[0111] The embodiments described above are some, but not all, of the embodiments of this application. The detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

Claims

1. An injectable tissue filler, characterized in that, The tissue filler is a colloidal solution comprising amphiphilic block copolymer microspheres, a solubilizer, and water, wherein the solubilizer is a polyhydroxy compound.

2. The injectable tissue filler according to claim 1, characterized in that, The polyhydroxy compound is selected from at least one of polyethylene glycol and glycerin; Optionally, the polyhydroxy compound is selected from polyethylene glycol, and the weight-average molecular weight of the polyethylene glycol is 200 to 2000.

3. The injectable tissue filler according to claim 1, characterized in that, In the tissue filler, the mass percentage of the solubilizer is 1-10%; or / and the mass percentage of the amphiphilic block copolymer microspheres is 10-50%.

4. The injectable tissue filler according to any one of claims 1 to 3, characterized in that, The average particle size of the amphiphilic block copolymer microspheres is 100~300 nm.

5. The injectable tissue filler according to any one of claims 1 to 3, characterized in that, In the amphiphilic block copolymer microspheres, the amphiphilic block copolymer is a diblock amphiphilic block copolymer; and / or the hydrophilic polymer is selected from at least one of methoxy polyethylene glycol, dihydroxy polyethylene glycol, monoalkoxy polyethylene glycol and monoacyl polyethylene glycol, and the hydrophobic polymer is selected from at least one of polycaprolactone, polylactic acid, polytrimethyl carbonate and polyhydroxybutyrate.

6. The injectable tissue filler according to any one of claims 1 to 3, characterized in that, The tissue filler also includes a pH adjuster, wherein the pH adjuster is selected from at least one of a phosphate system, a citrate-citrate system, and an acetate-acetate system; Optionally, in the tissue filler, the molar concentration of the pH adjuster is 10~50 mmol / L.

7. A method for preparing an injectable tissue filler as described in any one of claims 1 to 6, characterized in that, Includes the following steps: A solubilizer is mixed with water, wherein the solubilizer is a polyhydroxy compound, to obtain an aqueous solution. An amphiphilic block copolymer is provided, and the amphiphilic block copolymer is mixed with the aqueous solution to obtain a mixed solution; The mixed solution is stirred at a preset temperature, wherein the preset temperature is not less than the melting point of the amphiphilic block copolymer and not higher than the boiling point of water, so that the amphiphilic block copolymer self-assembles to form the amphiphilic block copolymer microspheres, thereby obtaining an injectable tissue filler.

8. The method for preparing the injectable tissue filler according to claim 7, characterized in that, The amphiphilic block copolymer is a diblock amphiphilic block copolymer, wherein the mass ratio of the hydrophilic polymer to the hydrophobic polymer in the amphiphilic block copolymer is 1:(1~10). Or / and, the weight average molecular weight of the hydrophilic polymer is 500~20000, and the weight average molecular weight of the hydrophobic polymer is 500~200000.

9. The method for preparing the injectable tissue filler according to claim 8, characterized in that, In the amphiphilic block copolymer, the hydrophilic polymer is selected from at least one of methoxy polyethylene glycol, dihydroxy polyethylene glycol, monoalkoxy polyethylene glycol, and monoacyl polyethylene glycol, and the hydrophobic polymer is selected from at least one of polycaprolactone, polylactic acid, polytrimethyl carbonate, and polyhydroxybutyrate; and in the step of stirring the mixed solution at a preset temperature, the preset temperature is 65~80℃.

10. The method for preparing the injectable tissue filler according to any one of claims 7 to 9, characterized in that, The aqueous solution also contains a pH adjuster, wherein the pH adjuster is selected from at least one of a phosphate system, a citrate-citrate system, and an acetate-acetate system; Optionally, in the aqueous solution, the molar concentration of the pH adjuster is 10~50 mmol / L.

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