CN117018287A

CN117018287A - Temperature-sensitive physical hydrogel freeze-dried preparation and preparation method and application thereof

Info

Publication number: CN117018287A
Application number: CN202310791376.8A
Authority: CN
Inventors: 陶秀梅; 吴鸣; 刘喆; 黄亭亭; 冷鸿飞; 徐小雨
Original assignee: Beijing Nuokangda Pharmaceutical Technology Co ltd
Current assignee: Beijing Nuokangda Pharmaceutical Technology Co ltd
Priority date: 2023-06-30
Filing date: 2023-06-30
Publication date: 2023-11-10

Abstract

The invention provides a temperature-sensitive physical hydrogel freeze-dried preparation, a preparation method and application thereof, wherein the preparation raw materials of the temperature-sensitive physical hydrogel freeze-dried preparation comprise temperature-sensitive polymers, sodium hyaluronate and phosphate buffer; the phase transition temperature of the thermosensitive polymer is 35+/-2 ℃; the molecular weight of the sodium hyaluronate is 220 ten thousand-280 ten thousand, and the mass volume ratio of the sodium hyaluronate to the phosphate buffer solution is 3-12mg:1ml. According to the invention, the sodium hyaluronate and the temperature-sensitive polymer with specific molecular weight and dosage are compounded, so that rapid gelation and transformation under the condition of physiological temperature are realized, an interpenetrating three-dimensional network structure is formed, the structural stability is better, the cell growth and repair are facilitated, the degradation time is long, and the inconvenience of repeated injection can be reduced. And the freeze-dried preparation can solve the problems of easy needle blocking, easy precipitation, easy degradation, poor stability and the like of microsphere products.

Description

Temperature-sensitive physical hydrogel freeze-dried preparation and preparation method and application thereof

Technical Field

The invention relates to the technical field of pharmaceutical chemicals, in particular to a temperature-sensitive physical hydrogel freeze-dried preparation and a preparation method and application thereof.

Background

In recent years, with the improvement of the living standard of people, the demands of medical and aesthetic products are continuously increased, and the continuous upgrading of the shaping and beauty technology and the products is promoted. In the field of micro-shaping, loving people are increasingly favouring filled products for non-invasive, immediate repair, which are widely accepted by consumers once they are marketed. The non-invasive and instant-repair injection filling molding product is generally used as a first choice of nose augmentation, chin filling, lip enlargement and anti-wrinkle filler, and has the functions of moisturizing, lubricating and shaping through direct injection into the dermis.

At present, most of hot instant filling injection is a preparation prepared by mixing 20-50 mu m-sized particles made of polycaprolactone PCL, polylactic acid PLA and other materials into an aqueous solution of carboxymethyl cellulose. After subcutaneous injection, the gel formed by the aqueous solution of the carboxymethyl cellulose can play a role in instant filling, then the microspheres in the preparation start to act along with the degradation of the gel, the degradation time of the microspheres in the preparation in vivo is controlled by adjusting the molecular weight of the polymer microspheres, and meanwhile, the long-acting effect of stimulating collagen regeneration is achieved.

The preparation is generally a pre-encapsulated injection, the gel preparation concentration of the preparation is usually higher in order to prevent uneven distribution and tissue inflammatory reaction caused by microsphere sedimentation and agglomeration, a thinner needle is generally used for reducing pain, and meanwhile, the microspheres in the body are prevented from being phagocytized to achieve a lasting stimulation effect, the particle size of the microspheres is often more than 40 mu m, and the preparation causes inconvenient procedures and is very easy to block the needle; on one hand, the microsphere preparation process generally adopts an emulsification-solidification-screening process, reagents such as methylene dichloride, polyvinyl alcohol and the like are required to be introduced in the process, the requirements of the reagents on the implantation preparation limit are low, the reagents are difficult to remove, and in order to achieve proper microsphere particle size distribution, a part of non-target particle size microspheres can be removed by screening, so that the process is complex, and the raw material cost is high; on the other hand, as the carboxymethyl cellulose gel is degraded after the preparation is implanted into a body, the structure of the carboxymethyl cellulose gel is easy to loosen, the gel viscosity is reduced, the cell adhesion is weak, the microspheres are difficult to support and stably suspend for a long time, and the risks of sedimentation and agglomeration of the microspheres and injection displacement exist. The dispersion and support of the microspheres become weak, which results in the microspheres not being uniformly dispersed, and the PCL and PLLA materials have poor affinity with tissues, so that tissues cannot be uniformly repaired.

Disclosure of Invention

The invention provides a temperature-sensitive physical hydrogel freeze-dried preparation, a preparation method and application thereof, which are used for solving the defects that microsphere products are easy to block needles, easy to precipitate, nodule and vascular embolism, easy to degrade a pre-encapsulation preparation, poor in stability and the like in the prior art, and realizing safe injection without blocking needles and pain and good filling effect.

In a first aspect, the invention provides a temperature-sensitive physical hydrogel freeze-dried preparation, wherein the preparation raw materials comprise a temperature-sensitive polymer, sodium hyaluronate and phosphate buffer;

the phase transition temperature of the thermosensitive polymer is 35+/-2 ℃;

the molecular weight of the sodium hyaluronate is 220 ten thousand-280 ten thousand, and the mass volume ratio of the sodium hyaluronate to the phosphate buffer solution is 3-12mg:1ml.

In an embodiment of the invention, the temperature-sensitive physical hydrogel freeze-dried preparation is prepared by mixing the preparation raw materials and freeze-drying.

The degradable amphiphilic block polymer is a typical temperature-sensitive material, is commonly used for injectable gel drug delivery systems, cartilage repair, tissue engineering scaffolds and the like, is a relatively mature implant material, but meets the requirement that the temperature-sensitive polymer which generates sol-gel phase transition at physiological temperature (namely, the phase transition temperature is 35+/-2 ℃) has low molecular weight and short degradation period, and is difficult to meet the requirement of long-acting medical filling. According to the invention, the sodium hyaluronate with specific molecular weight and dosage is compounded with the temperature-sensitive polymer, so that in-situ solidification filling can be realized, an interpenetrating three-dimensional gel network structure can be formed, the structural stability is better, the cell climbing growth is facilitated, the effective repair time is prolonged, namely, the degradation period is long and can reach more than 6 months, and the inconvenience caused by repeated injection is reduced. On the other hand, the invention abandons the pre-encapsulation product of the microspheres dissolved in gel, and prepares the freeze-dried preparation, which can effectively prevent the oxidative decomposition of the preparation and prolong the storage time. The freeze-dried preparation is an aqueous solution after being redissolved, is easy to inject, is convenient for doctors to operate, and solves the problem of easy needle blocking.

The phosphate buffer solution is prepared by dissolving disodium hydrogen phosphate and potassium dihydrogen phosphate in water, and is prepared by referring to three general rules of Chinese pharmacopoeia 2020, and a preparation method of the phosphate buffer solution (pH 7.3) in the 8004 buffer solution. The phosphate buffer solution has the functions of balancing salt and adjusting proper pH for buffering, so as to reduce discomfort of patients after injection.

In some embodiments of the invention, the thermosensitive polymer is an amphiphilic block copolymer having an ase:Sub>A-B type diblock, ase:Sub>A-B-ase:Sub>A type triblock, or B-ase:Sub>A-B type triblock structure, wherein ase:Sub>A represents ase:Sub>A hydrophilic segment, B represents ase:Sub>A hydrophobic segment, and the mass to volume ratio of the thermosensitive polymer to the phosphate buffer is 100-300mg:1ml. The concentration of the polymer in the phosphate buffer solution influences the phase transition temperature, and under the condition that other conditions are the same, the higher the concentration, the lower the phase transition temperature, namely the concentration, namely the mass-volume ratio of the thermosensitive polymer to the phosphate buffer solution exceeds the range, the phase transition temperature of 35+/-2 ℃ cannot be obtained.

Wherein the triblock structure is superior to the two-block structure.

In a preferred embodiment of the invention, the weight average molecular weight of the A segment is in the range of 800 to 4000, the weight average molecular weight of the B segment is in the range of 3000 to 7000, and the molecular weight ratio of the A, B segment is 1: (2-3), preferably 1:2.5.

the invention controls the weight average molecular weight and the proportion of the hydrophilic chain segment and the hydrophobic chain segment, can realize that the hydrophilic chain segment and the hydrophobic chain segment are dissolved into sol as soon as possible under the low-temperature condition, reduces the preparation difficulty of the sol, and is beneficial to the quick re-dissolution of freeze-dried preparations.

In an embodiment of the present invention, the a segment is a hydrophilic segment such as PEG, preferably PEG, and the B segment is one or more of hydrophobic segments such as PCL, PLA, PLLA, PLCA, PLGA. It is understood that PLA may have PDLA, PDLLA, in addition to PLLA form. For polymers such as PLCA and PLGA polymerized from two or more monomers, the ratio of the monomers may be any value.

In some embodiments of the invention, the thermosensitive polymer is PCL-PEG-PCL, PLCA-PEG-PLCA, PLGA-PEG-PLGA, PLLA-PEG-PLLA.

In a preferred embodiment of the invention, the temperature sensitive polymer is PLGA-PEG-PLGA.

It will be appreciated that the preferred conditions of the invention may be combined arbitrarily without conflict. For example, a preferred thermosensitive polymer of the present invention is PLGA-PEG-PLGA. Further preferably, the weight average molecular weight of PEG is in the range of 800-4000, the weight average molecular weight of PLGA is in the range of 3000-7000, and the molecular weight ratio of PEG to PLGA is 1: (2-3), more preferably 1:2.5.

in a second aspect, the present invention provides a method for preparing the above-described temperature-sensitive physical hydrogel lyophilized formulation.

The preparation method provided by the invention comprises the steps of mixing the preparation raw materials and freeze-drying.

In a specific embodiment of the present invention, the preparation method comprises: dissolving sodium hyaluronate in phosphate buffer solution at 4-10deg.C, dissolving temperature sensitive polymer in the phosphate buffer solution, packaging, and lyophilizing at-45-35deg.C.

According to the invention, the freeze-drying is carried out at the pre-freezing temperature of-45 to-35 ℃, and under the freeze-drying condition, the mutual effect result of the thermosensitive polymer and the sodium hyaluronate hydrophilic group is combined, so that the re-dissolution effect is uniform, and the re-dissolution time is short. Wherein, the temperature sensitive polymer needs to select the weight average molecular weight and the proportion of the preferable hydrophilic chain segment and the hydrophobic chain segment.

Further, the filling can be carried out in penicillin bottles according to a filling amount of 1 ml/bottle. Penicillin bottles are usually selected to have a volume of 5 ml. It will be appreciated that the use of pre-filled injections is also possible, but with a relatively short shelf life.

In a preferred embodiment of the present invention, the method for preparing the temperature-sensitive physical hydrogel lyophilized formulation comprises: adding HA into phosphate buffer solution according to the mass volume ratio of 8mg/ml at the temperature of 4-10 ℃, stirring for 0.5-1h until the HA is completely dissolved, then adding 200mg/ml of temperature sensitive polymer, continuously stirring for 1-2h until the HA is completely dissolved, then filling the HA into penicillin bottles according to the volume of 1 ml/bottle, and freeze-drying at the pre-freezing temperature of-40 ℃.

In a third aspect, the present invention provides an injectable tissue bulking agent comprising the above temperature sensitive physical hydrogel lyophilized formulation.

In an embodiment of the invention, the temperature sensitive physical hydrogel lyophilized formulation is reconstituted and then administered to the subject's target tissue either transdermally or subcutaneously. Modes of administration include, but are not limited to, injection.

The prepared temperature-sensitive physical hydrogel freeze-dried preparation is re-dissolved and then applied to the skin or the skin, sol-gel phase transition can be generated at physiological temperature, an in-situ solidification instant filling and repairing effect can be achieved on an application part, an interpenetrating three-dimensional network structure with higher stability can be formed, better cell adhesion is beneficial to cell proliferation, the risk of poor filling effect caused by subcutaneous displacement of gel is reduced, and the targeting positioning and lasting filling effects are achieved. The gel components have good biocompatibility and adjustable biodegradability, so that the risk of vascular embolism can be effectively avoided, and the operability of injection is improved. Therefore, the injection can be used as an injectable tissue filler in the fields of medicine, tissue repair and the like.

Further, the re-dissolution adopts water as the re-solution, and the dosage of the re-solution is equal to the sol volume of the temperature-sensitive physical hydrogel freeze-drying preparation before freeze-drying.

For example, if a phosphate buffer solution in which a thermosensitive polymer and sodium hyaluronate are dissolved is filled into penicillin bottles at a rate of 1 ml/bottle, and lyophilized, 1ml of water is used for reconstitution. It will be appreciated that the amount of complex solution allows errors to be present that do not affect the effectiveness of the application.

In some embodiments of the invention, the injectable tissue filler is adapted for injection through a 27-29G needle.

The invention adopts the 27-29G finer needle, which not only ensures the operation convenience of doctors, but also can reduce the pain of patients.

In order to further promote the filling effect and prevent adverse reactions after filling such as inflammation, the injectable tissue filler may further include a cell growth factor, an anti-inflammatory drug, etc., which may be added and mixed before the hydrogel is lyophilized.

Unless defined otherwise, the terms of science and technology used herein have the same meaning as commonly understood by one of ordinary skill in the art. Furthermore, as used in this specification, the singular noun encompasses the plural version of the noun without conflict with the context; plural nouns as used also encompasses singular versions of the noun.

The invention provides a temperature-sensitive physical hydrogel freeze-dried preparation and a preparation method and application thereof, and compared with the prior art, the invention at least comprises the following beneficial effects:

according to the invention, the sodium hyaluronate and the temperature-sensitive polymer with specific molecular weight and dosage are compounded, so that rapid gelation and transformation under the condition of physiological temperature are realized, an interpenetrating three-dimensional network structure is formed, the structural stability is better, the cell growth and repair are facilitated, the degradation time is long, and the inconvenience of repeated injection can be reduced.

Furthermore, the freeze-drying condition is optimally set, so that the freeze-drying preparation has short re-dissolution time, is convenient for clinical operation, solves the problems of short storage time, uneven dispersion, easy oxidative decomposition, sedimentation, needle blocking and the like of microsphere filling preparations, is in a liquid state during injection, can use thinner needles, and reduces the pain of patients.

Drawings

FIG. 1 is a schematic view of the structure of a gel after lyophilization according to example 1 of the present invention;

FIG. 2 is a diagram showing the gel of example 1 in transparent liquid state (left) after freeze-drying and in semitransparent gel state (right) after water bath at 37 ℃ in transparent liquid state;

fig. 3 is a chart showing collagen fiber proliferation by subcutaneous 400 x Masson staining after the hydrogel lyophilized preparation provided in example 1 of the present invention is reconstituted and implanted under the skin of an animal.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The experimental methods used in the following examples are conventional methods unless otherwise specified. Materials, reagents and the like used in the examples described below are commercially available unless otherwise specified.

The English abbreviations and Chinese abbreviations of some chemical substances related in the invention are compared as follows:

PCL: polycaprolactone

PLA: polylactic acid

PLLA: l-polylactic acid

PDLA: right-handed polylactic acid

PDLLA: racemized polylactic acid

PLCA: polylactic acid-citric acid

PLGA: polylactic acid-glycolic acid

PBS: phosphate buffer

HA: sodium hyaluronate.

Example 1

The embodiment provides a temperature-sensitive physical hydrogel freeze-dried preparation, which is prepared by the following steps:

the phosphate buffer solution is prepared by referring to three general rules of Chinese pharmacopoeia 2020 and a preparation method of phosphate buffer solution (pH 7.3) in 8004 buffer solution.

HA with 280 ten-thousandth molecular weight is added into phosphate buffer solution according to the mass volume ratio of 8mg/ml, and stirred for 0.5-1h at 500rpm until the HA is dissolved.

The temperature sensitive polymer: A. PLGA (5000) -PEG (2000) -PLGA (5000) with a B segment ratio of 1:2.5 was added to the above phosphate buffer with HA dissolved therein at 200mg/ml (still based on the volume of phosphate buffer alone, the same applies hereinafter), and stirred at 500rpm for 1-2h until dissolved.

Then, the mixture was filled into 5ml penicillin bottles at a rate of 1 ml/bottle, the pre-freezing temperature was set at-40℃and freeze-drying was performed according to the freeze-drying parameters shown in Table 1 below.

TABLE 1

And (5) sealing the freeze-dried product by a gland after the freeze-drying is finished to obtain the hydrogel freeze-dried preparation.

The gel structure of the lyophilized hydrogel preparation obtained in this example is schematically shown in fig. 1. From the figure, it can be seen that an interpenetrating three-dimensional gel network structure is formed, which is beneficial to the cell climbing growth.

Example 2

This example provides a temperature sensitive physical hydrogel lyophilized formulation which differs from example 1 in that:

the temperature sensitive polymer was added to the above phosphate buffer in which HA was dissolved at 100 mg/ml.

Example 3

the temperature sensitive polymer was added to the above phosphate buffer in which HA was dissolved at a concentration of 300 mg/ml.

Example 4

sodium hyaluronate HA was added to phosphate buffer at a mass to volume ratio of 3 mg/ml.

Example 5

This example provides a temperature sensitive physical hydrogel lyophilized formulation which differs from example 4 in that:

Example 6

Example 7

sodium hyaluronate HA was added to phosphate buffer at a mass to volume ratio of 12 mg/ml.

Example 8

This example provides a temperature sensitive physical hydrogel lyophilized formulation which differs from example 7 in that:

Example 9

Example 10

the pre-freeze temperature was set at-45℃and lyophilization was performed according to the lyophilization parameters shown in Table 2 below.

TABLE 2

Example 11

the pre-freeze temperature was set at-35℃and lyophilization was performed according to the lyophilization parameters shown in Table 3 below.

TABLE 3 Table 3

Example 12

the molecular weight of sodium hyaluronate HA is 220 ten thousand.

Example 13

temperature sensitive polymer: A. PCL (5000) -PEG (2000) -PCL (5000) with a B segment ratio of 1:2.5.

Example 14

temperature sensitive polymer: A. PLCA (4000) -PEG (2000) -PLCA (4000) with a B segment ratio of 1:2.5.

Example 15

temperature sensitive polymer: A. PLLA (6000) -PEG (2000) -PLLA (6000) with a B-segment ratio of 1:3.

Comparative example 1

This comparative example provides a temperature sensitive physical hydrogel lyophilized formulation which differs from example 1 in that:

sodium hyaluronate HA was added to phosphate buffer at a mass to volume ratio of 2 mg/ml.

Comparative example 2

This comparative example provides a temperature sensitive physical hydrogel lyophilized formulation which differs from comparative example 1 in that:

Comparative example 3

Comparative example 4

sodium hyaluronate HA was added to phosphate buffer at a mass to volume ratio of 13 mg/ml.

Comparative example 5

This comparative example provides a temperature sensitive physical hydrogel lyophilized formulation which differs from comparative example 4 in that:

Comparative example 6

Comparative example 7

the molecular weight of sodium hyaluronate HA is 200 ten thousand.

Comparative example 8

the molecular weight of sodium hyaluronate HA was 300 ten thousand.

Comparative example 9

temperature sensitive polymer: A. PLGA (2000) -PEG (2000) -PLGA (2000) with a B segment ratio of 1:1.

Comparative example 10

temperature sensitive polymer: A. PLGA (7000) -PEG (2000) -PLGA (7000) with a B segment ratio of 1:3.5.

Comparative example 11

the pre-freeze temperature was set at-50℃and lyophilization was performed according to the lyophilization parameters shown in Table 4 below.

TABLE 4 Table 4

Comparative example 12

the pre-freeze temperature was set at-30℃and lyophilization was performed according to the lyophilization parameters shown in Table 5 below.

TABLE 5

Experimental example

The following tests were performed on the hydrogel lyophilized formulations prepared in examples and comparative examples, respectively:

1. taking a hydrogel freeze-dried preparation of 1 penicillin bottle, injecting 1ml of pure water, pouring out the pure water after swirling for 5min onto a filter membrane with a pore diameter of 0.2 mu m, starting a vacuum pump for suction filtration, and observing whether unmelted film is contained on the filter membrane so as to judge whether freeze-dried gel is completely dissolved.

2. The solution gel dissolved according to the method 1 was returned to a liquid state at room temperature of 25 ℃, and after filling into a syringe, air was discharged, and the pushing force of the solution gel was measured under a pressure tester using a 29G needle. If the continuous force of the continuous sliding of the piston is less than or equal to 15N, the corresponding composition has moderate pushing force and good compliance for the operation of doctors.

3. Pouring the solution gel dissolved according to the method of detection 1 into a glass test tube, putting into a water bath kettle, heating in the water bath from 33 ℃ and heating to 38 ℃ each time by 1 ℃. And (3) carrying out water bath for 10min at each temperature to enable the gel to reach the water bath temperature, judging whether the current water bath temperature reaches the sol-gel transition temperature by a test tube inversion method, wherein the sol has no fluidity after phase transition, and does not flow after the test tube inversion, so that the phase transition temperature of the gel preparation of the formula is tested.

4. And (3) preserving the temperature of the gel obtained according to the detection 3 to 37 ℃, taking about 0.5ml of volume gel, placing the gel into a sample stage of a rheometer, testing the loss modulus and the storage modulus of the gel at different frequencies, and when the storage modulus is greater than the loss modulus, indicating that the gel is in a gel state at the frequency, otherwise, in a solution state, and testing the stability of the gel under different applicable scenes. The 1-10Hz is the daily vibration frequency of the gel, and the scanning range is 0.1-100Hz (refer to YYT0308-2015 medical sodium hyaluronate gel 5.8 shear viscosity).

The results of each group are shown in Table 6.

TABLE 6

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Wherein the hydrogel freeze-dried preparation obtained in examples 1-15 is transparent liquid after dissolution, and is semitransparent gel after water bath at 37 ℃ in transparent liquid state. FIG. 2 is a graphical representation of the sample of example 1 in a transparent liquid state (left) after dissolution and in a transparent liquid state (right) after a 37℃water bath.

5. 54 healthy New Zealand white rabbits are screened, the healthy New Zealand white rabbits are divided into 27 groups, each group is divided into 2, the samples prepared by the examples and the comparative examples are re-dissolved and injected into the subcutaneous parts of the left back and the right back, each rabbit is injected with 3 points at each side, each point is injected with 0.1ml, and each point is spaced by 2cm. Skin redness and swelling reactions were observed for 7 days. Two rabbits from each group were sacrificed for 1 month and 3 months, and the skin of the injection was collected and observed under a mirror for collagen proliferation, and the results are shown in Table 7.

TABLE 7

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In addition, fig. 3 is a graph showing collagen fibroproliferation of subcutaneous 400 x Masson staining 3 months after implantation of the sample into the animal after reconstitution of example 1, from which it can be seen that collagen fibroproliferation is evident in the tissue injection site.

6. The hydrogel lyophilized formulations prepared in example 1, example 13, example 14, example 15 in 24 vials each were taken, 7.28ml of the Sorensen buffer (for the preparation of the surgical implant polylactide copolymer and blend in vitro degradation test 4.2.1) was added to each vial, vortexed for 5min to dissolve, and the vessel was placed in a shaking water bath at 37.+ -. 1 ℃.2 degradation samples are taken from each group in each month, the content of lactic acid which is a degradation product is tested, and when the content of lactic acid reaches the maximum value and the concentration is not changed any more, the degradation is completely indicated (reference method: YYT 1806.1-2021 in-vitro degradation performance evaluation method of biomedical materials is used for degrading polyesters 5.4), and degradation tests are carried out on the samples of the examples.

Other than the absence of HA, lyophilized formulations of the same formulation as in example 1, example 13, example 14 and example 15 were prepared, designated as example 1', example 13', example 14 'and example 15', and degradation tests were performed in the same manner as described above, and the results are shown in Table 8.

TABLE 8

Group of	Degradation completion time
		Example 1	8 months of
Example 13	6 months of
		Example 14	For 5 months
Example 15	6 months of
		Example 1'	6 months of
Example 13'	For 5 months
		Example 14'	For 4 months
Example 15'	For 5 months

According to the experimental results, the high molecular sodium hyaluronate and the temperature-sensitive polymer are dissolved in the phosphate buffer solution to prepare the freeze-dried preparation, so that the oxidization can be effectively prevented, the polymer and the sodium hyaluronate are stable and are not easy to decompose, the hydrogel freeze-dried preparation is water-soluble and is easy to inject after being added with water for re-dissolution, the problems of instability, easy needle blocking and the like of the microsphere preparation are solved, and the compounded hydrophilic group of the sodium hyaluronate interacts with the hydrophilic group of the temperature-sensitive polymer, so that the re-dissolution rate is improved. After the freeze-dried preparation is re-dissolved and injected, when the temperature tends to physiological temperature, the aggregation degree of micelle formed by polymer in the solution is increased to generate gel phase change, and the micelle and sodium hyaluronate form an interpenetrating three-dimensional network structure, so that the structure stability is good, and the tissue filling effect is enhanced. In addition, the compounded high molecular sodium hyaluronate can accelerate the thermal gelation of the amphiphilic block copolymer, overcomes the defect of high degradation rate of the block copolymer, prolongs the degradation period, reduces the supplementary injection times, provides a cell climbing bracket structure, and is easy for tissue repair.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. The temperature-sensitive physical hydrogel freeze-dried preparation is characterized in that the preparation raw materials comprise temperature-sensitive polymer, sodium hyaluronate and phosphate buffer solution;

the phase transition temperature of the thermosensitive polymer is 35+/-2 ℃;

2. The temperature-sensitive physical hydrogel lyophilized formulation of claim 1, wherein the temperature-sensitive polymer is an amphiphilic block copolymer having ase:Sub>A type ase:Sub>A-B diblock, type ase:Sub>A-B-ase:Sub>A triblock, or type B-ase:Sub>A-B triblock structure, wherein ase:Sub>A represents ase:Sub>A hydrophilic segment, B represents ase:Sub>A hydrophobic segment, and the mass to volume ratio of the temperature-sensitive polymer to the phosphate buffer is 100-300mg:1ml.

3. The temperature-sensitive physical hydrogel lyophilized formulation of claim 2, wherein the weight average molecular weight of the a segment is in the range of 800-4000, the weight average molecular weight of the B segment is in the range of 3000-7000, and the molecular weight ratio of the A, B segments is 1: (2-3), preferably 1:2.5.

4. the temperature-sensitive physical hydrogel lyophilized formulation of claim 3, wherein the a segment is one or more of PEG and the B segment is PCL, PLA, PLLA, PLCA, PLGA;

preferably, the thermosensitive polymer is PLGA-PEG-PLGA.

5. A method for preparing a temperature-sensitive physical hydrogel lyophilized formulation according to any one of claims 1-4, wherein the preparation raw materials are mixed and lyophilized.

6. The method of preparing a temperature-sensitive physical hydrogel lyophilized formulation of claim 5, comprising: dissolving sodium hyaluronate in phosphate buffer solution at 4-10deg.C, dissolving temperature sensitive polymer in the phosphate buffer solution, packaging, and lyophilizing at-45-35deg.C.

7. An injectable tissue bulking agent comprising the temperature sensitive physical hydrogel lyophilized formulation of any of claims 1-4.

8. The injectable tissue bulking agent of claim 7, wherein the temperature sensitive physical hydrogel lyophilized formulation is administered transdermally or subcutaneously into the target tissue of the subject after reconstitution.

9. The injectable tissue bulking agent of claim 8, wherein the reconstitution solution is water in an amount equivalent to the sol volume of the temperature sensitive physical hydrogel lyophilized formulation prior to lyophilization.

10. The injectable tissue filler of any one of claims 7-9, wherein the injectable tissue filler is adapted for injection through a 27-29G needle.