KR100550057B1 - Cross-linked poloxamer, cross-linked poloxamer hydrogel and processes for preparing thereof - Google Patents

Abstract

The present invention relates to a crosslinked poloxamer, a hydrogel thereof, and a poloxamer macromer as an intermediate, and a method for preparing the same. The crosslinked poloxamer hydrogel of the present invention is easy to manufacture and has a high in vivo stability, and thus provides a carrier for drug delivery. It can be used as a tissue engineering support, artificial lens and in vivo implant material.

Poloxamer, poloxamer macromer, crosslinked poloxamer, crosslinked poloxamer hydrogel, intraocular lens

Description

Cross-linked poloxamer, cross-linked poloxamer hydrogel and processes for preparing etc}

1 shows infrared spectroscopy curves of poloxamer and poloxamer macromers.

2 shows the results of nuclear magnetic resonance analysis of poloxamer macromers.

)와 폴록사머 마크로머(

)의 농도에 따른 겔화 온도 변화를 나타낸다.3 is a poloxamer (

) And poloxamer macromers (

Changes in gelation temperature with concentration of).

4 shows X-ray diffraction analysis of poloxamer (-), poloxamer macromer (...) and crosslinked poloxamer hydrogel (...).

5 shows the differential thermal analysis curves of poloxamer and crosslinked poloxamer hydrogels.

6 shows the swelling degree of the crosslinked poloxamer hydrogel.

The present invention relates to crosslinked poloxamers, hydrogels thereof and methods for their preparation.

A polymer hydrogel is a polymer material that is insoluble in water but is swollen by water. Hydrogel is known to be used as a biomaterial because it can pass water molecules of small size, have a soft, low interfacial tension, easy purification, high water content, especially similar to the physical properties of the living body. Therefore, the hydrogel is used as artificial skin, a biomaterial in contact with blood, a carrier for drug delivery, and the like.

Poloxamer, which has conventionally been used as a material for hydrogel, is a terpolymer consisting of "poly (ethylene oxide)-poly (propylene oxide)-poly (ethylene oxide)" as shown in the following formula (1), a representative polymer One of the surfactants.

Equation (1):

Here, x, y, z are integers and are limited by the molecular weight of the poloxamer.

Poloxamer has little toxicity to human body and shows reversible sol-gel transition by heat, so it is used as a sustained-release drug delivery material in pharmacy, and also applied to biomaterials such as dressing for burn treatment and artificial skin. have.

However, poloxamer has a disadvantage that the gelation reaction occurs at a relatively high concentration, especially when the poloxamer gel is inserted into the human body is gradually diluted by the body fluid of the body and eventually becomes a sol, which cannot be used for long-term human insertion. There are disadvantages.

Accordingly, the present inventors have continued to study the development of a hydrogel that is stable and easy to manufacture even when inserted into the human body for a long time, thereby developing a poloxamer macromer as a crosslinked poloxamer, its hydrogel, and an intermediate material thereof.

That is, an object of the present invention is to provide a cross-linked poloxamer and a hydrogel thereof for biomaterials that are stable and easy to manufacture for a long time in the body, and a poloxamer macromer as an intermediate material and a method for producing the same.

The present invention provides a cross-linked poloxamer represented by the following formula (2) and a hydrogel thereof.

Crosslinked poloxamer means the high molecular compound shown by following formula (2).

Equation (2):

Wherein R is an alkyl group of C _n H _{2n + 1} , n is from 0 to 10; And

       x, y, z are integers and are limited by the molecular weight of the crosslinked poloxamer.

In the present invention, the molecular weight of the crosslinked poloxamer is preferably 10,000 to 5,000,000.

The crosslinked poloxamer hydrogel refers to that the crosslinked poloxamer is hydrated in a gel state, and 1 part by weight to 5 parts by weight of water per 1 part by weight of the crosslinked poloxamer. It is included.

The present invention also provides a method for producing the crosslinked poloxamer and hydrogel thereof.

In the present invention, a method for producing a crosslinked poloxamer and a hydrogel thereof includes the steps of preparing a poloxamer macromer having a crosslinkable functional group using a known poloxamer and crosslinking the poloxamer macromer in the presence of water. Preparing a crosslinked poloxamer hydrogel in which the poloxamer is hydrated in water.

In a first step, a step of preparing a poloxamer macromer having a crosslinkable functional group using a known poloxamer is as follows.

After dissolving the poloxamer in a solvent such as benzene, the amines (R ₃ N, where R can be the same or different as alkyl groups) and the acryloyl chloride derivative of formula (3) Reaction in the presence of) to prepare a poloxamer macromer of the following formula (4).

Equation (3):

R is an alkyl group of C _n H _{2n + 1} , and n is 0 to 10.

Equation (4):

Wherein R is an alkyl group of C _n H _{2n + 1} , n is from 0 to 10; And

        x, y, z are integers and are limited by the molecular weight of the poloxamer macromer.

The poloxamer macromer is a functional group capable of crosslinking at both ends of the poloxamer, and serves as a starting material for preparing the crosslinked poloxamer.

In the present invention, the molecular weight of the poloxamer macromer is 5,000 to 100,000, preferably 10,000 to 15,000.

  At this time, in the present invention, the poloxamer has a molecular weight of 5,000 to 100,000, preferably 10,000 to 15,000, and the polypropylene oxide content (abbreviation, PPO) in the poloxamer is 10 to 50% by weight, preferably 25 to 35% by weight is used.

The reaction temperature is carried out at 50 to 100 ° C, preferably 75 to 85 ° C, and the reaction time is about 1 to 5 hours, preferably about 2 to 4 hours.

After the reaction, the poloxamer macromer is precipitated and separated using a solvent capable of selectively dissolving the poloxamer and the poloxamer macromer, for example, normal hexane (n-hexane), and then dried.

In a second step, the poloxamer macromer prepared above is placed in a photoinitiator solution in the presence of water and irradiated to prepare a crosslinked poloxamer hydrogel.

By the distilled water present during the reaction, the crosslinked poloxamer of formula (2) is present as a crosslinked poloxamer hydrogel hydrated in water. In order to obtain only the crosslinked poloxamer, the crosslinked poloxamer hydrogel prepared above may be dried to remove moisture.

While various conventional photoinitiators can be used in the reaction, preferred photoinitiator solutions include photoinitiator 2,2-dimethoxy-2-phenylacetophenone (N, vinyl pyrrolidone) N-vinyl pyrrolidone) is preferable.

In the above reaction, the selection of an optimal radiation ray is determined by the type of photoinitiator, and ultraviolet light is generally preferred. The crosslinking time by ultraviolet rays is 1 to 30 minutes, preferably about 3 to 10 minutes.

In this reaction, the temperature of the distilled water for dissolving the poloxamer is 1 to 15 ° C, preferably 3 to 8 ° C.

In the gelation of poloxamer macromer, in addition to the crosslinking by photopolymerization mentioned above, a general polymer crosslinking method such as crosslinking by thermal polymerization may be used. In the crosslinking by thermal polymerization, when the poloxamer macromer is heated, the double bond of the end group (-CR = CH ₂ ) is broken and radicals are generated to generate a crosslinking reaction.

Hereinafter, the present invention will be described by specific examples, but the present invention is not limited by the following examples.

Example 1.

As poloxamer, poloxamer 407 having a molecular weight of 12,600 and a polypropylene oxide content of 30% by weight was used. 25.2 g of poloxamer 407 was dissolved in benzene at 75 ° C. and reacted with 0.59 g of triethylamine and 0.34 g of acryloyl chloride at 80 ° C. for 3 hours. Triethylaminehydrochloride was removed by filtration, and poloxamer macromer was precipitated using normal hexane and dried.

To the solution of the above prepared poloxamer macromer in distilled water at 5 ° C., 25 μl of a photoinitiator solution prepared by dissolving 2,2-dimethoxy-2-phenylacetophenone as a photoinitiator in N-vinyl pyrrolidone was added. Then, it irradiated for 5 minutes with the low energy ultraviolet ray lamp, and produced the crosslinked poloxamer hydrogel. The prepared crosslinked poloxamer hydrogel was lyophilized.

Experimental Example 1.

1 is an infrared spectroscopic analysis result of poloxamer and poloxamer macromer (using Midac M series spectrometer). It can be seen that both the poloxamer and poloxamer macromers exhibit COC stretching bands at 1110.7 cm ⁻¹ . The poloxamer macromers showed peaks due to C = O stretching at 1724 cm ⁻¹ , while the poloxamers showed no peaks, indicating that poloxamer macromers were produced.

2 is a nuclear magnetic resonance analysis curve of a poloxamer macromer (using a 600 MHz High Resolution NMR spectrometer). In the case of the poloxamer macromer, the peak of the acrylate group, which does not appear in the poloxamer, was present at 5.79 to 6.43 ppm, and the formation of the poloxamer macromer was confirmed.

Figure 3 shows the hydrogelation temperature of poloxamer and poloxamer macromers. The gelation temperature according to the concentration of poloxamer in water was lowered as the concentration of poloxamer increased. Poloxamer macromers were also confirmed to have similar gelation behavior as poloxamers.

4 is an X-ray diffraction analysis result for observing the crystal structure change (small-angle X-ray scattering with general area detector diffraction system. Using GADDS). As shown in FIG. 4, the poloxamers showed crystal peaks at Bragg angles of 19.2 °, 23.5 °, and 26.2 °, and the diffraction peaks by these crystal planes were confirmed to be the same in the case of the crosslinked poloxamer hydrogel. However, the scattering by the amorphous region was increased in the case of the crosslinked poloxamer hydrogel.

5 is a differential thermal analysis of poloxamer and crosslinked poloxamer hydrogel (using TA Instrument, DSC 2910). The melting temperature of the crosslinked poloxamer hydrogel was about 10 ° C lower than the poloxamer's melting temperature (60 ℃), and the melt enthalpy was 60 J / g, which was lower than that of poloxamer (106 J / g). The results were in agreement with. This result was judged as a phenomenon that appeared because the crystallization of the crosslinked poloxamer hydrogel is interrupted by the substitution of a large end group.

6 shows the swelling degree of the crosslinked poloxamer hydrogel. Here, swelling degree was computed by the following formula as swelling degree in 37 degreeC.

Swelling (wt%) = (Ws-Wd) / Wd x 100

Where Ws is the weight of the swollen sample and Wd is the dry weight.

The swelling degree of the crosslinked poloxamer hydrogel decreased as the concentration of the poloxamer macromer decreased as the crosslinking density increased.

As a result of measuring the compressive strength of the crosslinked poloxamer hydrogel in the wet state, the compressive stress with respect to the compression length gradually increased and then increased sharply after the initial compression period (Minimat, Rhometric Scientific). Initial compressive modulus was calculated from the stress-strain curve and is shown in Table 1. The compressive strength of the crosslinked poloxamer hydrogel was almost constant (between 92.6 kPa and 101.7 kPa) regardless of the hydrogel concentration.

Table 1. Initial Compressive Strength of Crosslinked Poloxamer Hydrogels

22 wt% 18 wt% 14 wt% Initial modulus (kPa) 99.7 101.7 92.6 Standard Deviation 16.21 23.70 17.26

From the above results, it was confirmed that the poloxamer macromer and the crosslinked poloxamer hydrogel were formed. The newly prepared crosslinked poloxamer hydrogel was found to have a lower melting temperature and superior strength as compared to the conventional poloxamer gel, and was also considered to have excellent stability since the gel was formed by covalent bonding.

As described above, the crosslinked poloxamer hydrogel of the present invention is easy to manufacture and has high stability in vivo, and thus may be used as a drug delivery carrier, a tissue engineering support, an intraocular lens and a silver implant material. .

Claims (11)

Molecular Weight 10,000 To 5,000,000 crosslinked poloxamer of the formula:

Wherein R is an alkyl group of C _n H _{2n + 1} , n is from 0 to 10; And         x, y, z are integers and are limited by the molecular weight of the crosslinked poloxamer. A crosslinked poloxamer hydrogel comprising 1 to 5 parts by weight of water per 1 part by weight of the crosslinked poloxamer of claim 1. After dissolving the poloxamer in a solvent, the amines (R ₃ N, where R is the same or not the same as each other as an alkyl group) and reacted in the presence of acryloyl chloride derivative of the following formula Manufacturing Method:

R is an alkyl group of C _n H _{2n + 1} , and n is 0 to 10. 4. The process for producing poloxamer macromers according to claim 3, wherein the amine is triethylamine and the acryloyl chloride derivative is acryloyl chloride. The method for producing a poloxamer macromer according to claim 3, wherein the reaction temperature is 50 to 100 ° C and the reaction time is 1 to 5 hours. The method for producing a poloxamer macromer according to claim 3, wherein the poloxamer has a molecular weight of 5,000 to 100,000 and a content of polypropylene oxide in the poloxamer is 10 to 50% by weight. A method for producing the crosslinked poloxamer hydrogel of claim 2, wherein the poloxamer macromer prepared by the method of claim 3 is crosslinked by irradiation in the presence of water and a photoinitiator solution. The method for producing a crosslinked poloxamer hydrogel according to claim 7, wherein the photoinitiator solution has dissolved 2,2-dimethoxy-2-phenylacetophenone in N-vinyl pyrrolidone. The method for producing a crosslinked poloxamer hydrogel according to claim 7, wherein the crosslinking reaction is carried out by irradiation with ultraviolet rays. The method for producing a crosslinked poloxamer hydrogel according to claim 9, wherein the crosslinking time by ultraviolet rays is 1 to 30 minutes. Poloxamer macromers having the molecular weight of 5,000 to 100,000: .

Wherein R is an alkyl group of C _n H _{2n + 1} , n is from 0 to 10; And               x, y, z are integers and are limited by the molecular weight of the poloxamer macromer.

Images