CN111218013B - Preparation method and application of crosslinked polymer - Google Patents

Abstract

The invention relates to a preparation method and application of a cross-linked polymer. The preparation method comprises the following steps: taking sodium carboxymethyl cellulose and galactose and stirring and dissolving them in water to obtain a mixture, then adding a cross-linking agent, stirring and dissolving, and adjusting the system The polymerization reaction is carried out to the reaction temperature, and the reaction is completed, and the pH of the reaction product is adjusted to 1-5 to obtain the cross-linked polymer; the cross-linking agent used in the reaction is citric acid and its derivatives; the cross-linked polymer is used for preparing soluble microneedles Has good solubility and mechanical strength. The drug-loaded soluble microneedles can release up to 0.1033 mg. Compared with the prior art, the present invention has the advantages of good moisture resistance, good solubility, simple and easy preparation method, and high drug release amount during drug loading.

Description

A kind of preparation method of cross-linked polymer and its application

technical field

The invention belongs to the technical field of microneedles, and in particular relates to a preparation method and application of a cross-linked polymer.

Background technique

Inspired by mosquito bites to obtain blood, if the transdermal drug delivery system can form microchannels in the skin layer through microneedles, the drug enters the blood circulation through the microchannel, and solves the obstacle of the drug passing through the skin stratum corneum barrier, which will greatly enhance the drug's efficacy. Bioavailability, improve drug efficacy. Compared with the traditional syringe, the microneedle is divided into two parts, one part is the tip part that contains most of the drug; the other part is the base part that mainly plays a supporting role. Polymer microneedles have attracted attention due to their excellent biocompatibility, biodegradability, low toxicity, strength and toughness, and low cost; soluble microneedles have avoided the biocompatibility issues of silicon, metal, and other insoluble microneedles It has the characteristics of convenient production and preparation, rapid drug release, and no secondary damage. A promising microneedle dosage form for drug delivery. In the prior art, the preparation method of drug-loaded soluble microneedles is divided into two steps: first, the drug is dissolved in the water-soluble raw material mixture, and secondly, the solution is injected into the microneedle mold by centrifugation or vacuum method , drying, and demoulding to obtain drug-loaded soluble microneedles.

Studies have shown that dissolvable microneedles prepared from biocompatible materials have defects such as insufficient hardness to penetrate the stratum corneum of the skin due to the high hygroscopicity of the material, or too high viscosity, which is not conducive to preparation and molding. Therefore, forming composite materials with biocompatible materials to improve their properties is one of the ways to solve the problem.

Puerarin has poor water solubility and fat solubility, the solubility in water is only 4.62 mg/mL, and it is difficult to absorb after oral administration, and its bioavailability is only 3.799%, which is low. "Chinese Pharmacopoeia" 2015 edition). Injectable administration requires specialized medical staff, and the injection materials are mostly disposable materials, which not only generate medical waste but also have low patient compliance; oral delivery methods require multiple administrations due to low bioavailability. Therefore, it is of great significance to develop a new dosage form of puerarin with high efficiency and environmental protection.

SUMMARY OF THE INVENTION

The first object of the present invention is to provide a method for preparing a cross-linked polymer in order to overcome the defect that the above-mentioned prior art is not resistant to moisture;

The second object of the present invention is to provide a method for preparing soluble microneedles that can improve the poorly water-soluble drugs in order to overcome the defects of the puerarin drug in the prior art that it is not easy to use and has low bioavailability, so as to realize the poorly water-soluble drug. The preparation of drug-soluble microneedles reduces drug waste and improves the safety of microneedles.

The object of the present invention can be realized through the following technical solutions:

A method for preparing a cross-linked polymer, comprising the following steps: taking sodium carboxymethyl cellulose and galactose and stirring and dissolving them in water to obtain a mixture, then adding a cross-linking agent, stirring and dissolving, adjusting the system to a reaction temperature to carry out a polymerization reaction, and reacting After the end, the PH of the reaction product is adjusted to be 1-5 to obtain the cross-linked polymer; the cross-linking agent is citric acid and its derivatives.

The reaction temperature is 50°C to 80°C; the reaction time of the polymerization reaction is 5h to 10h.

The reaction temperature was 50°C, and the reaction time was 10 h.

The ratio of the sodium carboxymethyl cellulose to galactose is 1 g: 1-3 g.

The added amount of the citric acid is 10% to 20% of the mass of the mixture.

The present invention also provides the application of a cross-linked polymer, the cross-linked polymer is used to prepare a soluble microneedle, and the soluble microneedle includes a base and a needle tip; the preparation includes the following steps:

(1) Preparation of the needle tip part: take a microneedle mold, use a pipette to take a polymer solution and spread it on the surface of the microneedle mold, and carry out the first centrifugation to obtain the needle tip part;

(2) Preparation of the base part: take out the microneedle mold, use a pipette to take the polymer solution and spread it on the surface of the microneedle mold, and perform a second centrifugal treatment to obtain the base part;

(3) Preparation of soluble microneedles: the microneedle mold is taken out, and after drying treatment, the microneedle mold is peeled off to obtain the soluble microneedles.

The centrifugal rotation speed of the first centrifugal treatment and the second centrifugal treatment is 3000-4500 r/min, and the time is 60-90 minutes, preferably the centrifugal rotation speed is 3000 r/min, and the time is 60 minutes.

The drying treatment is drying at 40-45°C for 24h-48h, preferably at 40°C for 48h.

In the step (1), a poorly water-soluble drug is first added to the polymer solution, and the mixture is uniformly dissolved and mixed to obtain a poorly water-soluble drug mixture, which is used to make the needle tip.

In the step (1), the poorly water-soluble drug is puerarin.

Further, the concentration of puerarin in the poorly water-soluble drug mixture is 20 mg/mL.

To facilitate the visual observation of the double-layered microneedle, two different color dyes can be added to the polymer mixture, which are respectively used to make the needle tip and the base part.

In the step (1), trypan blue is firstly added to the polymer solution, and the trypan blue mixed solution is obtained by dissolving and mixing uniformly, and the trypan blue mixed solution is used to make the needle tip part.

In the step (2), rhodamine is first added to the polymer solution, and the rhodamine mixture is uniformly dissolved and mixed to obtain a rhodamine mixture, and the rhodamine mixture is used to make the needle tip part.

Further, the concentration of trypan blue in the trypan blue mixture is 0.1 mg/mL, and the concentration of rhodamine in the rhodamine mixture is 0.1 mg/mL.

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

(1) Compared with the uncrosslinked simple polymer, the cross-linked polymer prepared by the present invention not only has better anti-humidity performance, but also the solubility does not affect the drug release;

(2) Galactose and sodium carboxymethyl cellulose are used as the main materials of double-layer microneedles. The materials are simple and easy to obtain polymer composite materials with good biocompatibility, high safety and good solubility; mechanical properties Good, able to penetrate the skin;

(3) The operation of preparing the double-layer microneedle is simple. The present invention can realize good adhesion between the microneedle part and the base part only at room temperature. The method is simple and easy to implement, does not require special equipment and manufacturing process, and is suitable for Promote use.

Description of drawings

Fig. 1 is the photo of dissolvable microneedle in embodiment 1;

Fig. 2 is the infrared spectrogram of the crosslinked polymer in embodiment 2 and embodiment 3;

Fig. 3 is the moisture absorption rate test result of the crosslinked polymer in embodiment 2;

Fig. 4 is the dissolving situation of soluble microneedle in embodiment 2;

Fig. 5 is the moisture absorption rate test result of the crosslinked polymer in embodiment 3;

Fig. 6 is the dissolving situation of soluble microneedle in embodiment 3;

Fig. 7 is the puncture performance test of in vitro porcine skin puncture performance of soluble microneedle in Example 3;

FIG. 8 shows the drug release of the puerarin-loaded microneedles in the soluble microneedles in Example 4. FIG.

Detailed ways

The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

Example 1

(1) Preparation of a cross-linked polymer, accurately weigh 1.0g d-galactose, 1.0g sodium carboxymethylcellulose, dissolve in 20mL deionized water, dissolve at room temperature, and accurately weigh the mass fraction of 20% lemon Acid, stir to dissolve, mix completely, react in a water bath at 50°C for 10 hours, and adjust pH=5 with 50% NaOH to obtain a cross-linked polymer;

(2) using the above-mentioned cross-linked polymer to further manufacture soluble microneedles: measure 2 mL of the cross-linked polymer in step (1), add trypan blue, and mix evenly to obtain a 0.1 mg/mL trypan blue mixed solution;

(3) Weigh 2 mL of the polymer in step (1), add Rhodamine B dye, and mix evenly to obtain 0.1 mg/mL Rhodamine B mixed solution;

(4) Put the microneedle mold into a 5mL small centrifuge tube, pipette 300μL of the mixture of step (2), and spread it on the surface of the mold; set the centrifugation speed to 3000 rpm, and centrifuge for 60 minutes for the first time ,take out. Carry out the second pipetting of 500 μL of the mixture in step (3), and repeat the first operation. Take out the mold, put the mold into a 40°C oven for 48 hours, take it out, peel off the mold, and obtain microneedles as shown in FIG. 1 .

As can be seen from Figure 1, the cross-linked polymer in this example was successfully prepared by twice centrifuging and once drying in an oven at 40°C to obtain soluble microneedles with the shape of a tip and a base.

Example 2

(1) Preparation of a cross-linked polymer, accurately weigh 1.0g d-galactose, 1.0g sodium carboxymethylcellulose (CMC), dissolve in 20mL deionized water, dissolve at room temperature, and accurately weigh the mass fraction as 20% citric acid, stirred to dissolve, mixed completely, reacted in a water bath at 50°C for 10h, pH=1, the infrared test of the cross-linking result is shown in Figure 2, and it can be seen from Figure 2 that the infrared spectrum of the product of Example 2 There is a new ester bond peak at 1725.66cm ^-1 in the figure, indicating the successful ester formation with citric acid. It was shown that the cross-linking polymerization of sodium carboxymethyl cellulose and galactose occurred, and the cross-linked polymer was successfully prepared.

(2) drying the cross-linked polymer in step (1) at 40°C in an oven to form a film, weighing the mass of the film at this time with a precision balance, placing it at an air temperature of 30°C, and placing a cup of 100mL water for drying The pot was placed in a simulated constant humidity environment, placed in it for 5h, 10h, 15h, 20h, and 25h, and then taken out and weighed with a precision balance to calculate the moisture absorption rate of the polymer at different time points under the same humidity. As a comparative experiment, 1.0 g of galactose and 1.0 g of sodium carboxymethyl cellulose were accurately weighed, dissolved in 20 mL of deionized water, dissolved at room temperature, dried to form a film, and placed under the same conditions to measure the uncrosslinked The moisture absorption rate of the polymer, the results are shown in Figure 3. It can be seen from Figure 3 that when the air temperature is 30 °C, the uncrosslinked polymer increases with time, from 14.33% of the moisture absorption rate at 5h to 25h. The moisture absorption rate of the cross-linked polymer increased from 4.51% at 5 h to 16.43% at 25 h. The moisture absorption rate of the uncross-linked polymer was much higher than that of the cross-linked polymer with the increase of time, indicating that through the The moisture absorption rate of the cross-linked polymer after chemical cross-linking with citric acid is lower than that of the uncross-linked polymer, which improves the moisture resistance of the un-cross-linked polymer.

(3) Solubility test: In order to observe the solubility of microneedles prepared from cross-linked polymers, the microneedles were pressed on the isolated pig skin for 1h, 3h, 7h, 10h, 12h, and 24h, and the changes of the microneedles were observed as shown in the figure. 4. As can be seen from Figure 4, the microneedle tip shape was observed under a microscope after being inserted into the pig skin for a certain period of time.

Example 3

(1) For the preparation of a cross-linked polymer, accurately weigh 1.0 g of d-galactose and 1.0 g of sodium carboxymethyl cellulose, dissolve in 20 mL of deionized water, dissolve at room temperature, and accurately weigh 20% of the Citric acid, stirred to dissolve, mixed completely, reacted in a water bath at 50 °C for 10 hours, and adjusted pH=5 with 50% NaOH. The infrared spectrum is consistent with the infrared spectrum of CMC-galactose cross-linked polymer, indicating that the cross-linking polymerization of sodium carboxymethyl cellulose and galactose occurs, and the cross-linked polymer is successfully prepared.

(2) drying the polymer in step (1) at 40°C to form a film, weighing the film at this time with a precision balance, and then placing it in a drying pot with an air temperature of 30°C and a cup of 100 mL of water In a simulated constant humidity environment, put it in it for 5h, 10h, 15h, 20h, 25h, take it out and weigh the mass with a precision balance, and calculate the moisture absorption rate of the polymer at different time points under the same humidity, which is convenient for comparison, and will be accurately weighed. 1.0g of galactose, 1.0g of sodium carboxymethylcellulose, dissolved in 20mL of deionized water, dissolved at room temperature, dried to form a film, and placed under the same conditions to measure the moisture absorption rate of the uncrosslinked polymer, the results are as follows Figure 5. It can be seen from Figure 5 that when the air temperature is 30°C, the moisture absorption rate of the uncrosslinked polymer is greater than that of the crosslinked polymer, indicating that the uncrosslinked polymer has poor moisture resistance.

(3) Solubility test: In order to observe the solubility of microneedles prepared from cross-linked polymers, the microneedles were pressed on the isolated pig skin for 5 min, 7 min, 9 min and 15 min, and the morphological changes of the microneedles were observed as shown in Figure 6. The volume of the microneedles decreased gradually with the prolongation of residence, indicating that the prepared microneedles had good solubility.

(4) Microneedle puncture performance test of isolated pigskin: remove the residual water on the skin surface with filter paper before using the isolated pigskin, place the dermis side down and fix it on the experimental table, and stick the microneedle with a 1000N weight. The tablet was administered vertically and removed after 30s. The obvious pinhole array pattern was shown in Figure 7. It can be seen from Figure 7 that the micro-needle in vitro pig skin puncture performance test showed that 1000N force was applied to the Double-layer microneedle, obvious perforation on the surface of pig skin, good mechanical hardness.

Example 4

Preparation and drug release test of puerarin-loaded microneedles

(1) Accurately weigh 1.0g d-galactose, 1.0g sodium carboxymethylcellulose, dissolve in 20mL deionized water, dissolve at room temperature, accurately weigh 20% citric acid, stir to dissolve, and mix completely, The reaction was carried out in a water bath at 50 °C for 10 h, and the pH was adjusted to 5 with 50% NaOH.

(2) Measure 4 mL of the cross-linked polymer solution in step (1), accurately weigh puerarin, dissolve, and mix evenly to obtain a 20 mg/mL puerarin mixed solution.

(3) Put the microneedle mold into a 5mL small centrifuge tube, transfer the mixture of step (2) with a pipette, and spread it on the mold surface; set the centrifugal speed to 3000 rpm, and centrifuge for 60 minutes for the first time, take out. Perform the second pipetting of the mixture in step 1, and repeat the first operation. The mold was taken out, and then the mold was placed in a 40° C. oven for 48 hours, taken out, and the mold was peeled off to obtain puerarin-loaded microneedles.

(4) In order to study the drug release of puerarin-loaded microneedles in vitro, 100 microneedles were completely dissolved in deionized water, and the total amount of puerarin in the microneedles was determined by ultraviolet-visible spectrophotometry (UV-VIS). . Then insert the microneedles prepared under the same conditions into the isolated pig skin, remove the microneedles from the pig skin after a certain period of time, and then put the microneedles into deionized water to completely dissolve them, and use ultraviolet-visible spectrophotometry (UV-VIS spectrophotometry). ) to measure the content of the remaining puerarin in the microneedles, and calculate the amount of puerarin released into the pig skin as shown in Figure 8. It can be seen from Figure 8 that the in vitro drug release of 100 puerarin-loaded microneedles increases with time, and the maximum drug release amount is 0.1033 mg.

The invention has passed the microneedle puncture performance test of the in vitro pigskin, and the results show that when a force of 1000 N is applied to the double-layered microneedle, obvious perforations appear on the surface of the pigskin, and the pigskin has good mechanical hardness. After being inserted into the pig skin for a certain period of time, the shape of the microneedle tip was observed under a microscope, and the volume of the microneedle gradually decreased with the prolongation of the stay, indicating that the prepared microneedle had good solubility. The humidity test results showed that the air temperature was 30°C and the humidity was 25.05%. When the microneedles to be tested were put on hold for 25 hours, the moisture absorption rate of the cross-linked microneedles dropped to 16.43% and the shape of the microneedles remained unchanged. Under the maximum drug loading of puerarin, the maximum drug release of 100 microneedles obtained from the mold was 0.1033 mg. Based on the therapeutic dose of puerarin injection of 100mg to 200mg, the prepared 10 microneedles can satisfy the administration, and the area is equivalent to the area of 9cm*12cm of commonly used plaster patches; the invention provides a new type of cross-linked polymer soluble The preparation method of the microneedle sticker is simple and easy to operate, does not require special equipment and manufacturing process, and is easy to operate.

Example 5

(1) Preparation of a cross-linked polymer, accurately weigh 1.0g d-galactose, 3.0g sodium carboxymethylcellulose, dissolve in 20mL deionized water, dissolve at room temperature, and accurately weigh the mass fraction of 10% lemon Acid, stir to dissolve, mix completely, react for 5h under 80 ℃ water bath condition, adjust pH=5 with 50% NaOH to obtain cross-linked polymer;

(2) using the above-mentioned cross-linked polymer to further manufacture soluble microneedles: measure 2 mL of the cross-linked polymer in step (1), add trypan blue, and mix evenly to obtain a 0.1 mg/mL trypan blue mixed solution;

(3) Weigh 2 mL of the polymer in step (1), add Rhodamine B dye, and mix evenly to obtain 0.1 mg/mL Rhodamine B mixed solution;

(4) Put the microneedle mold into a 5mL small centrifuge tube, pipet 300μL of the mixed solution in step (2), and spread it on the surface of the mold; set the centrifugation speed to 4500 rpm, and centrifuge for 90 minutes for the first time ,take out. Carry out the second pipetting of 500 μL of the mixture in step (3), and repeat the first operation. The mold was taken out, and then the mold was placed in a 45° C. oven for drying for 24 hours, taken out, and the mold was peeled off to obtain microneedles as shown in FIG. 1 .

As can be seen from Figure 1, the cross-linked polymer in this example was successfully prepared by twice centrifuging and once drying in an oven at 40°C to obtain soluble microneedles with the shape of a tip and a base.

Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above-mentioned specific embodiments, and those skilled in the art can make various variations or modifications within the scope of the claims, which do not affect the essential content of the present invention.

Claims (5)

1. The application of a cross-linked polymer is characterized in that the cross-linked polymer is used for preparing a soluble microneedle, and the soluble microneedle comprises a base and a needle tip; the preparation method comprises the following steps:

(1) preparation of the needle tip part: taking a microneedle mould, using a pipette to take a cross-linked polymer solution to be flatly laid on the surface of the microneedle mould, and carrying out first centrifugal treatment to obtain the needle tip part;

(2) preparation of the base part: taking out the microneedle mould, using a pipette to take the cross-linked polymer solution to be flatly laid on the surface of the microneedle mould, and carrying out second centrifugal treatment to obtain the base part;

(3) preparation of soluble microneedles: taking out the microneedle mould, drying, and peeling off the microneedle mould to obtain the soluble microneedle;

the crosslinked polymer is prepared by the following method:

stirring and dissolving sodium carboxymethylcellulose and galactose in water to obtain a mixture, adding a cross-linking agent, stirring and dissolving, adjusting the system to the reaction temperature for polymerization, and adjusting the pH of a reaction product to 1-5 after the reaction is finished to obtain the cross-linked polymer; the cross-linking agent is citric acid and derivatives thereof;

the reaction temperature is 50-80 ℃; the reaction time of the polymerization reaction is 5-10 h;

the ratio of the sodium carboxymethylcellulose to the galactose is 1g: 1-3 g;

the addition amount of the citric acid is 10% -20% of the mass of the mixture.

2. The use of a crosslinked polymer according to claim 1, wherein the first and second centrifugation are performed at a centrifugation speed of 3000 to 4500 rpm for 60 to 90 minutes.

3. The use of a crosslinked polymer according to claim 2, wherein the drying treatment is drying at 40-45 ℃ for 24-48 h.

4. The use of a crosslinked polymer according to claim 1, wherein in step (1), the poorly water soluble drug is added to the crosslinked polymer solution, and the mixture is dissolved and mixed uniformly to obtain a poorly water soluble drug mixture, wherein the poorly water soluble drug mixture is used for manufacturing the needle tip portion.

5. The use of a crosslinked polymer according to claim 4, wherein in step (1), the poorly water-soluble drug is puerarin.

Images