阅读说明：本技术 一种冻干粉末及其制备方法与应用 (Freeze-dried powder and preparation method and application thereof ) 是由 穆树花 左保燕 马丽端 陈成军 于 2021-07-30 设计创作，主要内容包括：本发明涉及医疗制剂技术领域,具体公开了一种冻干粉末及其制备方法与应用。本发明的冻干粉末的制备方法,所述冻干粉末包含层状化磷脂,在冻干时,预冻温度为-20～-40℃；冻干溶剂为叔丁醇与辅助溶剂组成的混合溶剂；所述辅助溶剂为环己烷、DMSO、1,4-二氧六环、环己醇和2-甲基-2-丁醇中的一种或两种,所述辅助溶剂占混合溶剂体积的1％-9％。本发明方法既可以达到叔丁醇单独作为冻干溶剂时制得产品的微泡的浓度和数量,又有效提高了预冻温度,利于工业化生产。(The invention relates to the technical field of medical preparations, and particularly discloses freeze-dried powder and a preparation method and application thereof. The preparation method of the freeze-dried powder comprises the lamellar phospholipid, and the pre-freezing temperature is-20 to-40 ℃ during freeze-drying; the freeze-drying solvent is a mixed solvent consisting of tert-butyl alcohol and an auxiliary solvent; the auxiliary solvent is one or two of cyclohexane, DMSO, 1, 4-dioxane, cyclohexanol and 2-methyl-2-butanol, and accounts for 1% -9% of the volume of the mixed solvent. The method of the invention not only can reach the concentration and the quantity of the microbubbles of the product prepared when the tert-butyl alcohol is independently used as the freeze-drying solvent, but also effectively improves the pre-freezing temperature and is beneficial to industrial production.)

1. A method for preparing a freeze-dried powder comprising a layered phospholipid, characterized in that, during freeze-drying, the pre-freezing temperature is between-20 ℃ and-40 ℃; the freeze-drying solvent is a mixed solvent consisting of tert-butyl alcohol and an auxiliary solvent; the auxiliary solvent is one or two of cyclohexane, DMSO, 1, 4-dioxane, cyclohexanol and 2-methyl-2-butanol, and accounts for 1% -9% of the volume of the mixed solvent.

2. The preparation method according to claim 1, wherein the freeze-drying solvent is a mixed solvent of tert-butanol and 2-methyl-2-butanol, and the 2-methyl-2-butanol accounts for 3-5% of the volume of the mixed solvent.

3. The method according to claim 2, wherein the freeze-drying solvent is a mixed solvent of t-butanol and 2-methyl-2-butanol, and 2-methyl-2-butanol accounts for 3% of the volume of the mixed solvent.

4. The method according to any one of claims 1 to 3, wherein the lamellar phospholipid is prepared from a phospholipid selected from one or more of DMPC, DPPC, DSPC, DMPG-Na, DPPG-Na, DSPG-Na, DSPE-PEG2000, DPPE-PEG5000, and a fatty acid which is palmitic acid; the mass ratio of the phospholipid to the fatty acid is (9-11): 1.

5. the method of claim 4, wherein the lyophilized powder further comprises a stabilizer of a lamellar phospholipid, the stabilizer being polyethylene glycol, mannitol, sucrose, or PVP; the mass ratio of the stabilizer to the lamellar phospholipid is (50-60): 1.

6. the method for producing according to claim 5, wherein the layered phospholipid is composed of distearoylphosphatidylcholine, dipalmitoylphosphatidylglycerol sodium, and palmitic acid.

7. The method according to claim 6, wherein the mass ratio of distearoylphosphatidylcholine to dipalmitoylphosphatidylglycerol sodium to palmitic acid is (4-5): (4-5): 1, preferably 4.75:4.75: 1.

8. The preparation method according to claim 7, wherein the stabilizer is polyethylene glycol 4000, and the mass ratio of the polyethylene glycol 4000 to the lamellar phospholipid is (58-58.5): 1.

9. a lyophilized powder produced by the production method according to any one of claims 1 to 8.

10. An ultrasound contrast agent comprising the lyophilized powder of claim 9.

Technical Field

The invention relates to the technical field of medical preparations, in particular to freeze-dried powder and a preparation method and application thereof.

Background

The ultrasonic contrast agent is a solution suspended with bubbles with the diameter of a few microns, and is a diagnostic reagent for enhancing medical ultrasonic detection signals. The first generation of ultrasound contrast agents is microbubble contrast agents encapsulating air, such as commercial products, namely Levovist and Albune, which are on the market, and the ultrasound contrast agents are influenced by arterial pressure due to small molecular weight, have short duration and are easy to rupture, so that the clinical application is limited to a certain extent. The second generation ultrasonic contrast agent is mainly obtained by wrapping fluorocarbon or sulfur hexafluoride gas by shell membranes of various materials, such as commercially available products of SonoVue, Optison, FS069, Echogen and the like, and has the characteristics of low solubility, capability of generating better harmonic signals by microbubbles and the like, so that myocardial development can be realized. One of the commonly used preparation methods of the contrast agents is to prepare freeze-dried powder capable of forming microbubbles, and when the contrast agent is used, physiological saline is added to the freeze-dried powder to form the gas-filled microbubble contrast agent.

At present, the freeze-dried powder for forming gas-filled microvesicles is prepared by dissolving powdered or layered phospholipid and polyethylene glycol 4000 in t-butanol, prefreezing at-45 deg.C and vacuum drying to remove the solvent. Lower prefreezing temperature can make solution crystallize fast, and the quick-freeze not only can make the solute not separate out in advance by utilizing transient supersaturated state, has avoided the change of solute microenvironment among the freeze-drying process to a certain extent moreover, makes the freeze-dried product more even, forms higher microbubble concentration after redissolving, and the microbubble that makes is wrapped up by the phospholipid monomolecular layer, and volume concentration can reach 10⁸The method has better stability. However, the technology needs a pre-freezing temperature of-45 ℃ and quick freezing at low temperature, which is very strict for equipment in industrial production, and the low quick-freezing temperature not only has large production energy consumption, but also limits production batch, so that the industrial mass production is difficult, just as the patent CN112165959A, the production batch can only reach thousands of branches.

Therefore, in view of the above problems, it is desirable to develop a more optimal method for preparing lyophilized powder for forming gas-filled microvesicles.

Disclosure of Invention

Aiming at the problems of the prior art, the invention aims to provide a preparation method of freeze-dried powder for forming gas-filled microvesicles, which has low process energy consumption, mild environmental requirements and high industrial implementation degree.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a method for preparing a freeze-dried powder comprising a layered phospholipid, wherein the pre-freezing temperature is-20 to-40 ℃ during freeze-drying; the freeze-drying solvent is a mixed solvent consisting of tert-butyl alcohol and an auxiliary solvent; the auxiliary solvent is one or two of cyclohexane, DMSO, 1, 4-dioxane, cyclohexanol and 2-methyl-2-butanol, and accounts for 1% -9% of the volume of the mixed solvent.

The lyophilized powder of the present invention is mixed with a physiologically acceptable gas (e.g., SF)₆) Filling, and adding normal saline to compound to form the gas-filled microvesicle when in use.

The invention focuses on the fact that in the prior art, when lamellar phospholipid is subjected to freeze drying, the pre-freezing temperature is low, and the industrial production is not facilitated. Further, a great deal of research and investigation finds that after a plurality of organic solvents are combined in a specific mode to serve as a freeze-drying solvent system, the existing pre-freezing temperature can be increased, and the effect which is the same as that of pre-freezing at minus 45 ℃ is achieved at a higher pre-freezing temperature.

According to the scheme of the invention, the organic solvents are specifically matched, so that the organic solvents can jointly exert a synergistic effect, and the organic solvents are not negatively influenced after being matched with each other, so that the concentration and the number of the microbubbles of the product prepared when the tert-butyl alcohol is independently used as a freeze-drying solvent can be reached, the pre-freezing temperature is effectively increased, the obtained freeze-dried product is uniform, the number and the particle size of the microbubbles after re-dissolution are ideal, and the problem of industrial production caused by the excessively low quick-freezing temperature is solved.

Preferably, the freeze-drying solvent is a mixed solvent composed of tert-butyl alcohol and 2-methyl-2-butyl alcohol, and the 2-methyl-2-butyl alcohol accounts for 3% -5% of the volume of the mixed solvent.

More preferably, the freeze-drying solvent is a mixed solvent composed of tert-butyl alcohol and 2-methyl-2-butyl alcohol, and 2-methyl-2-butyl alcohol accounts for 3% of the volume of the mixed solvent.

To facilitate the formation of microbubbles with higher number and volume concentrations at higher prefreezing temperatures.

In the invention, the lamellar phospholipid is prepared from phospholipid and fatty acid, the phospholipid is selected from one or more of DMPC, DPPC, DSPC, DMPG-Na, DPPG-Na, DSPG-Na, DSPE-PEG2000 and DPPE-PEG5000, and the fatty acid is palmitic acid; the mass ratio of the phospholipid to the fatty acid is (9-11): 1.

in the invention, the freeze-dried powder also comprises a stabilizer of the layered phospholipid, and the stabilizer is an auxiliary material which can increase the viscosity of the solution, such as polyethylene glycol, mannitol, sucrose, PVP and the like; the mass ratio of the stabilizer to the lamellar phospholipid is (50-60): 1.

preferably, the layered phospholipid consists of distearoylphosphatidylcholine, dipalmitoylphosphatidylglycerol sodium and palmitic acid to facilitate the formation of a stable phospholipid membrane.

More preferably, the mass ratio of the distearoyl phosphatidylcholine to the dipalmitoyl phosphatidylglycerol sodium to the palmitic acid is (4-5): (4-5): 1, and more preferably 4.75:4.75:1, to facilitate the formation of stable microbubbles.

In the invention, preferably, the stabilizing agent is polyethylene glycol 4000, and the mass ratio of the polyethylene glycol 4000 to the layered phospholipid is (58-58.5): 1, to facilitate microbubble stabilization.

As a specific embodiment, the preparation method of the present invention comprises:

(1) preparing a layered phospholipid;

(2) dissolving the layered phospholipid and polyethylene glycol 4000 in the freeze-drying solvent, filtering and sterilizing, and freeze-drying at a pre-freezing temperature of-20 to-40 ℃.

The invention also provides a freeze-dried powder prepared by the preparation method.

The invention also provides an ultrasonic contrast agent which comprises the freeze-dried powder.

The lyophilized powder of the present invention can be used for preparing an ultrasound contrast agent, in particular by mixing the lyophilized powder with a physiologically acceptable gas (e.g., SF)₆) Filling, and uniformly mixing with water for injection during use to obtain gas-filled microvesicle suspension used as an ultrasonic contrast agent.

The invention has the beneficial effects that:

the method adopts a mild pre-freezing process, can realize tens of thousands of products in production batches, and ensures that the Microbubble Volume Concentration (MVC), the microbubble concentration and the particle size of freeze-dried products in each batch are stable and reproducible, thereby being applicable to freeze-drying of various lamellar phospholipids.

The freeze-drying solvent system ensures that the solute cannot be separated out in advance when the solution to be freeze-dried is freeze-dried at a slow cooling rate (the pre-freezing temperature is high, so that the cooling rate is low), the layered structure of the phospholipid cannot be damaged due to the change of the microenvironment of the solute in the freeze-drying process, the quality of the product is improved, the obtained freeze-dried product is uniform, and the number and the particle size of the redissolved microbubbles are ideal. The change not only can obviously reduce the production energy consumption, has mild production conditions, but also improves the industrial implementation degree of products, and improves the production batch to tens of thousands of products per batch.

Detailed Description

Preferred embodiments of the present invention will be described in detail with reference to the following examples. It is to be understood that the following examples are given for illustrative purposes only and are not intended to limit the scope of the present invention. Various modifications and alterations of this invention will become apparent to those skilled in the art without departing from the spirit and scope of this invention.

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

Experimental example 1

The experimental example provides a preparation method of freeze-drying microvesicles in the prior art, and compares the influence of two freeze-drying modes on the product effect.

1. Preparation of lyophilized microvesicles:

lyophilized microvesicles were prepared according to the method disclosed in example 2 of patent CN 112165959A: adding 190mg of DSPC, 190mg of DPPG-Na and 40mg of PA into 84ml of hexane/ethanol (8/2, v/v) mixed solvent, stirring until the solution is dissolved, evaporating the solvent to dryness under vacuum condition, adding 24.56g of PEG4000, adding 500ml of tert-butyl alcohol after mixing, heating to about 60 ℃ for dissolution, filtering by a 0.22 mu m filter membrane, filling into 8ml of injection bottles, semi-pressing for plugging, and respectively carrying out freeze-drying by adopting a quick freezing mode (the pre-freezing temperature is-45 ℃) and a slow freezing mode (the pre-freezing temperature is-30 ℃), wherein the specific freeze-drying procedure is as follows: 1) pre-freezing: pre-cooling the sample on a shelf to-45 ℃ or-30 ℃ and maintaining the sample for 10 hours to completely freeze the solution; 2) sublimation: the vacuum degree is maintained at 0.02mbar, the shelf temperature is-20 deg.C, maintained for 7 hr, the shelf temperature is 0 deg.C, maintained for 2 hr, and the shelf temperature is maintainedThe temperature is 40 ℃, and the temperature is maintained for 2 h. SF for the upper part of the injection bottle at the end of the lyophilization₆Saturated and the injection vial was sealed with a rubber stopper.

2. Evaluation of gas-filled microvesicle suspensions:

preparation of gas-filled microvesicle suspension, the lyophilized product to be tested prepared in the above step is poured into 5ml of 0.9% sodium chloride solution, the bottle is shaken vigorously for 20 seconds, 50 μ l to 100ml of the suspension is sucked out of the 0.9% sodium chloride solution, and after uniform mixing, the average Microvesicle Volume Concentration (MVC) and average microvesicle concentration of the gas-filled microvesicle suspension are determined using a Counter Multisizer 3 (Coulter particle Counter and particle size analyzer) with a 30 μm bore tube.

3. Results, see table 1:

TABLE 1

Sample information	MVC(μl/ml)	Microbubble concentration (pieces/ml)
			Tert-butyl alcohol quick-frozen (-45 ℃ C.)	5.59	3.81×108
Slow freezing of tert-butyl alcohol (-30 deg.C)	0.14	1.18×106

It can be known that when the microbubbles are prepared according to the patent CN112165959A, MVC (model number) in the quick-freezing process and the volume concentration of the microbubbles are obviously higher than those in slow freezing, the product effect of the slow freezing process is poor.

Example 1

This example provides a method of preparing a lyophilized powder of the present invention and demonstrates the effect thereof.

1. Preparation and evaluation of lyophilized microvesicles

The procedure for preparation of the layered phospholipid and mixing with PEG4000 was the same as in Experimental example 1. Then, 500ml of tert-butyl alcohol/2-methyl-2-butanol (97/3, v/v) mixed solvent is added, the temperature is raised to about 60 ℃ for dissolution, a 0.22 mu m filter membrane is filtered and filled into 8ml injection bottles, the freeze-dried microbubbles are prepared by adopting a slow freezing mode (-30 ℃) to freeze the lyophilized microbubbles (the specific freeze-drying procedure is the same as the experimental example 1), and SF is used above the injection bottles when the freeze-drying is finished₆Saturated and the injection vial was sealed with a rubber stopper. The method of evaluating the suspension of gas-filled microvesicles was the same as in experimental example 1.

2. Results were analyzed, see table 2:

TABLE 2

Example 2

This example provides a method for preparing a lyophilized powder of the present invention, and verifies the effect thereof, and the specific methods for preparing and evaluating lyophilized microbubbles are the same as example 1 except that the lyophilization solvent is tert-butanol and 2-methyl-2-butanol, and the volume ratio of the two solvents is 95: 5.

The evaluation results are shown in Table 3:

TABLE 3

Example 3

This example provides a method for preparing a lyophilized powder of the present invention, and verifies the effect thereof, and the specific methods for preparing and evaluating lyophilized microvesicles are the same as those of example 1 except that the lyophilization solvent is tert-butanol and DMSO at a volume ratio of 99: 1.

The evaluation results are shown in Table 4:

TABLE 4

Example 4

This example provides a method for preparing a lyophilized powder of the present invention, and verifies the effect thereof, and the specific methods for preparing and evaluating lyophilized microvesicles are the same as those of example 1 except that the solvents for lyophilization are tert-butanol and 1, 4-dioxane, and the volume ratio of the two is 91: 9.

The evaluation results are shown in Table 5:

TABLE 5

Example 5

This example provides a method of preparing a lyophilized powder of the present invention and demonstrates the effect thereof.

The lyophilized microvesicles were prepared as in example 1, except that 110mg of DPPC and 320mg of DSPE-PEG2000 were used as the phospholipids. The selection and the dosage of the fatty acid and the stabilizer are unchanged; the prefreezing temperature was-20 ℃.

The evaluation method was the same as in example 1, and the results are shown in Table 6:

TABLE 6

Example 6

This example provides a method of preparing a lyophilized powder of the present invention and demonstrates the effect thereof.

The preparation method of the freeze-dried microvesicle is the same as that of example 1, except that 225mg of DMPC and 210mg of DSPG-Na are used as phospholipids when the layered phospholipids are prepared; the stabilizer was 27g of mannitol. The amount of PA used was constant. The prefreezing temperature was-40 ℃.

The evaluation method was the same as in example 1, and the results are shown in Table 7:

TABLE 7

Comparative example 1

This comparative example provides a method of preparing a lyophilized powder.

The preparation method of the freeze-dried microvesicles was the same as that of example 1 except that 2-methyl-2-butanol was present in an amount of 11% by volume of the mixed solvent.

Comparative example 2

This comparative example provides a method of preparing a lyophilized powder.

The preparation method of the freeze-dried microvesicle is the same as that of example 1, except that the freeze-drying solvent is tert-butyl alcohol and ethanol, and the volume ratio of the tert-butyl alcohol to the ethanol is 97: 3.

Comparative example 3

This comparative example provides a method of preparing a lyophilized powder.

The preparation method of the specific freeze-dried microvesicle is the same as that in example 1, the difference is that the freeze-drying solvent is tert-butyl alcohol and water, and the volume ratio of the tert-butyl alcohol to the water is 95: 5.

experimental example 2

The average particle diameter, MVC, microbubble concentration, and reconstitution state properties of the products of experimental example 1, each of the above examples, and comparative examples were evaluated and summarized as follows.

The evaluation methods are respectively as follows: the average volume particle size (. mu.m), average MVC (. mu.l/ml), average microbubble concentration (. mu.l/ml) were reported by a Coulter Counter Multisizer 3 in the same manner as in Experimental example 1; the reconstitution stability was evaluated by adding 5ml of 0.9% sodium chloride solution to the sample, shaking the sample vigorously to prepare microbubbles, and observing the time for maintaining the white foam state.

The results are shown in Table 8:

TABLE 8

And (4) conclusion: as can be seen from the results of the examples and comparative examples, in which the average MVC, average microbubble concentration and reconstitution stability of the samples are significantly deteriorated when the kind and ratio of the solvents are not within the range defined by the present invention, freeze-drying of the selected mixed solvent of the present invention can achieve results similar to that achieved by single-use tert-butyl alcohol freeze-drying.

Although the invention has been described in detail hereinabove with respect to a general description and specific embodiments thereof, it will be apparent to those skilled in the art that modifications or improvements may be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.