JP2007231095A - Visible light curable material and wound healing promoter - Google Patents

Abstract

Provided is a visible light curable material that can be gelled under less invasive conditions by irradiation with visible light with lower illuminance, and is suitable for application to medical materials such as hemostatic agents.
In a visible light curable material that is cured in a gel form upon irradiation with visible light, the compound includes a compound having a photosensitive group that generates radicals upon irradiation with visible light, and a disubstituted amino group-containing compound. A visible light curable material characterized in that the compound has gelatin modified with eosin and at least one of cinnamic acid, meth (a) acrylic acid and vinylbenzoic acid. It contains a di-substituted amino group-containing compound and gelatin modified with eosin or the like, and gels by cross-linking by a recombination reaction between radicals generated from the di-substituted amino group-containing compound and modified gelatin. A wound healing promoter such as a hemostatic agent comprising the visible light curable material. By using gelatin as a gelling substrate, a foreign body reaction does not occur in the living body, and degradability according to the wound healing process can be obtained, which is suitable for medical applications such as hemostatic agents.

Description

  The present invention relates to a visible light curable material that is cured in a gel state by irradiation with visible light, and a wound healing promoter such as a hemostatic agent using the visible light curable material.

  Gelatin is a heat-denatured protein of collagen and is a living body-derived polymer, so it has excellent biocompatibility. Therefore, hydrogel obtained by cross-linking gelatin by various methods is used as a sustained-release carrier for drugs. Applications to various medical materials such as cell scaffolds, surface modifying materials, and wound healing promoters such as hemostatic agents are being studied.

  Conventionally, as a crosslinking method of gelatin, as a crosslinking agent, a method using aldehydes containing glutaraldehyde, a method using carbodiimide, N-hydroxysuccinimide, or the like has been used, but these crosslinking methods are harmful crosslinking agents. And the use of reagents, it is necessary to remove unreacted compounds by a washing operation; it takes time to cure and it is difficult to produce a hydrogel directly in vivo.

  On the other hand, a crosslinking method utilizing a photoreaction is also known, and this method has the advantage that the toxicity of the compound used is low, the curing time is as short as several minutes, and only the irradiated site can be locally gelled. is there.

  The present inventors have studied various photoreactive gelatins that can be gelled under visible light irradiation under less invasive conditions. With eosinized gelatin into which eosin, a kind of xanthene pigment, has been introduced, and hydrogen donors. It has been found that gelation occurs when a certain mixed solution of ascorbic acid is irradiated with visible light.

  However, as shown in Comparative Example 4 to be described later, a mixed solution of eosinized gelatin and N, N-dimethylaminopropylacrylamide homopolymer has good yield in only 1 minute when irradiated with 99000 lx visible light. A gel can be obtained at a high rate, but such high-illumination visible light irradiation is not preferable because it involves damage to the living tissue because the irradiation involves high heat. On the other hand, when the illuminance of visible light to be irradiated is reduced to 7700 lx as in Comparative Examples 1 to 3 described later, the gel forming ability is also reduced. In this case, the irradiation time is required to obtain a gel ratio of 60% or more. Needed to be increased to about 10 minutes.

  The present invention is a visible light curable material that can be gelled under less invasive conditions by irradiation with visible light with lower illuminance, and suitable for application to medical materials such as hemostatic agents, and the visible light curing. An object of the present invention is to provide a hemostatic agent using a functional material.

  The visible light curable material of the present invention comprises a compound having a photosensitive group that generates a radical by irradiation with visible light and a disubstituted amino group-containing compound in a visible light curable material that is cured in a gel form by irradiation with visible light. And the compound having the photosensitive group is gelatin modified with eosin and at least one of cinnamic acid, meth (a) acrylic acid and vinylbenzoic acid. Note that meth (acrylic acid) is a general term for methacrylic acid and methacrylic acid. Vinyl benzoic acid is a compound in which a vinyl group is introduced at the carboxyl group and para positions of benzoic acid.

  That is, in order to find a photoreactive gelatin having high gelation efficiency, the present inventors first examined a crosslinking mechanism of a mixed solution of eosinized gelatin and ascorbic acid by irradiation with visible light, and estimated as follows.

  When a mixed system of eosinized gelatin and ascorbic acid is irradiated with visible light, eosin excited by irradiation with visible light extracts hydrogen from ascorbic acid and generates radicals as described below. Here, since ascorbic acid is a two-electron reducing agent, two molecules of eosin radical are generated by reaction with one molecule of ascorbic acid. It is considered that gelatin is cross-linked by recombination between the generated eosin radicals to form a gel.

  That is, ascorbic acid itself is not directly involved in cross-linking, and the present inventors believe that this is one of the causes of low gelation efficiency in a mixed system of eosinized gelatin and ascorbic acid. It was.

  Therefore, the present inventors examined a compound having a disubstituted amino group such as a dimethylamino group as a hydrogen donor. When a compound having a di-substituted amino group is used, radicals are generated from both eosin and di-substituted amino groups by irradiation with visible light, and three types of radical recombination reactions may occur as shown below. That is, if a compound having a disubstituted amino group, preferably a disubstituted methyl group, is used, it can also be used as a crosslinking agent, and gel formation can be promoted.

  As a result of further research, the present inventor has reduced the amount of modification of eosin with respect to gelatin because eosin absorbs visible light, and instead has a light-absorbing property of visible light or a significantly small photosensitive group, specifically Is modified with at least one of cinnamic acid, meth (a) acrylic acid and vinylbenzoic acid, so that it can be sufficiently crosslinked even if the amount of eosin modification is reduced and the amount of light irradiation can be reduced. It has been found that gelatin gels in a short time.

  In the present invention, the compound having a photosensitive group is gelatin modified with eosin and at least one of cinnamic acid, meth (a) acrylic acid and vinylbenzoic acid.

  Hereinafter, at least one of cinnamic acid, meth (a) acrylic acid, and vinyl benzoic acid may be referred to as “vinyl carboxylic acid”.

  In the present invention, the disubstituted amino group-containing compound is preferably a dimethylamino group-containing compound.

  Specifically, dimethylamino groups such as 1,1,4,7,10,10-hexamethyltrimethylenetetramine (HMTETA), a copolymer of dimethylacrylamide and dimethylaminoethyl methacrylate (DMAA-DMAEMA copolymer), etc. Examples thereof include a copolymer of a vinyl monomer and a water-soluble monomer, and a polymer of a vinyl monomer having a dimethylamino group such as polydimethylaminopropylacrylamide (PDMAPAAm).

  In this case, the visible light curable material of the present invention preferably contains a dimethylamino group-containing compound and a modified gelatin having a photosensitive group modified with eosin and a vinyl carboxylic acid. It is gelled by cross-linking by radical recombination reaction between radicals generated from modified gelatin having a group.

  In such a visible light curable material, it is preferable to contain 0.001 to 30% by weight of a dimethylamino group-containing compound with respect to the modified gelatin having a photosensitive group, and in particular, the concentration of the modified gelatin having a photosensitive group is 1.0 to 30%. It is preferable to add a dimethylamino group-containing compound to a 30.0% by weight aqueous solution.

  The visible light curable material of the present invention preferably has a gelation rate of 10% or more when irradiated with visible light having an illuminance of 10 to 10,000 lx for 1 to 600 seconds. The visible light curable material of the present invention has a degree of swelling of 100 or less when cured into a gel.

The gelation rate and the degree of swelling are calculated by the following formulas 1 and 2, respectively.
Formula 1: Gelation rate (%) = W _dry / W _solid × 100
Formula 2: Swelling degree = (W _wet −W _dry ) / W _dry

Here, W _solid is the weight of the mixed solution before crosslinking by light irradiation, W _wet is the weight when a material crosslinked by light irradiation is immersed in water at 37 ° C. for 15 hours, and W _dry is the water absorbing gel. Is the weight after drying using a vacuum pump.

  The wound healing promoter of the present invention is characterized by comprising such a visible light curable material of the present invention, and is useful as, for example, a hemostatic agent.

  The visible light curable material of the present invention can be efficiently gelled with a relatively low illuminance by irradiating visible light with a relatively low illuminance and with minimal influence on the living body. Therefore, it is useful as various medical materials such as sustained release carriers of drugs, cell scaffolds, surface modifying materials, wound healing promoting materials such as tissue adhesives and hemostatic agents.

  The visible light curable material of the present invention can obtain a degradability according to the wound healing process without causing a foreign body reaction in vivo by using gelatin as a gelling substrate. It is suitable for medical applications such as a wound healing promoter.

  Hereinafter, embodiments of the visible light curable material and the wound healing promoter of the present invention will be described in detail.

  The di-substituted amino group-containing compound used in the present invention is not particularly limited as long as it is a compound that becomes a hydrogen donor and generates a radical by irradiation with visible light, and has 1 to 10 carbon atoms such as a dimethylamino group-containing compound. And a compound containing an amino group substituted with an alkyl group, or a diarylamino group-containing compound such as a diphenylamino group.

  The larger the number of disubstituted amino groups contained in the disubstituted amino group-containing compound, the more radicals are generated, which is preferable. Therefore, the disubstituted amino group-containing compound preferably contains two or more disubstituted amino groups such as a dimethylamino group. Two or more disubstituted amino groups contained in one molecule of the disubstituted amino group-containing compound may be the same or different.

  Hereinafter, in the visible light curable material of the present invention, the present invention will be described by exemplifying a case where a dimethylamino group-containing compound is included as the disubstituted amino group-containing compound. Is not limited to dimethylamino group-containing compounds.

  In the visible light curable material of the present invention, gelatin having excellent biocompatibility is preferably used as a gelling substrate. In particular, gelatin, eosin and vinyl carboxylic acids (cinnamate, meth (acrylic) acrylic acid and vinyl are used. It is preferable to use a gelation mechanism in which at least one kind of benzoic acid) is used in combination.

  The gelatin used in the present invention may be ordinary gelatin having a molecular weight of 5,000 to 100,000 and about 10 to 100 amino groups / molecule.

  Gelatin modified with eosin and vinyl carboxylic acid is prepared by introducing eosin into the side chain of gelatin to give eosinized gelatin according to the following reaction, and then introducing vinyl carboxylic acid into the side chain of gelatin. The

A specific example will be described as follows.
(1) Formed by condensing the carboxyl group in the eosin molecule with the amino group of the side chain of gelatin by the action of water-soluble carbodiimide, N-ethyl-N ′-(3-dimethylaminopropyl) carbodiimide (WSC) It is introduced by an amide bond. After introduction, purify by dialysis. The amount of introduction is preferably 1 to 5 eosin molecules, particularly 1 to 3 per molecule of gelatin. When the number of introduced eosin is small, the gelation rate is lowered, and when it is excessively large, the influence degree of visible light absorption of eosin becomes strong, and the visible light irradiation amount increases.
(2) Subsequently, vinyl carboxylic acid (cinnamic acid, meth (a) acrylic acid, vinyl benzoic acid) is introduced into gelatin. The amino group which is free in the side chain of eosinized gelatin and the carboxyl group of vinyl carboxylic acid are introduced into eosinized gelatin via an amide bond formed by condensation in the presence of WBC. Thereafter, it is purified again by dialysis. The introduction amount is preferably 1 to 10 molecules per molecule of gelatin for any of cinnamic acid, meth (a) acrylic acid and vinylbenzoic acid.

  The number of compounds having a photosensitive group such as eosin introduced into the gelatin molecule is, for example, based on the molar absorption coefficient of eosin (ε = 94755) measured by measuring the absorbance of an aqueous solution of eosinized gelatin at a maximum absorption wavelength of 523 nm. It can be calculated.

  Examples of the di-substituted amino group-containing compound used together with the photosensitive compound-modified gelatin modified with eosin and vinyl carboxylic acid include N, N-dimethylaminopropylacrylamide N, N-dimethylacrylamide, and 2- (dimethyl One type of polymer or two or more types of copolymers selected from the group consisting of amino) ethyl acrylate are preferable, and the molecular weight Mn is preferably 5,000 to 100,000. Further, 1,1,4,7,10,10-hexamethyltriethylenetetramine (HMTETA) can be used. A structural formula of a copolymer of a vinyl monomer having a dimethylamino group such as HMTETA, DMAA-DMAEMA copolymer and a water-soluble monomer, and a polymer of a vinyl monomer having a dimethylamino group such as PDMAPAAm is shown below.

  The DMAA-DMAEMA copolymer preferably has a molecular weight of about 500 to 50,000, and the ratio m: n between the DMAA and DMAEMA is preferably about 9: 1 to 1: 9. Even in this range, the more DMAA, the stronger the nonionic nature of the copolymer and the lesser the nature as a hydrogen donor. As a result, the crosslinkability may be reduced, but on the other hand, the cytotoxicity is lowered. There are advantages. On the other hand, when the amount of DMAEMA is large, the cationicity of the copolymer becomes strong, and an improvement in crosslinkability can be expected, but there is also a concern about an increase in cytotoxicity. That is, the monomer ratio in these copolymers may be appropriately set by those skilled in the art in consideration of the light to be irradiated, the time, the place to be irradiated, etc. when used for a living body.

  PDMAPAAm preferably has a molecular weight of about 500 to 50,000.

  In both PDMAPAAm and DMAA-DMAEMA copolymers, if the molecular weight is too small, the amount to be mixed with eosinized gelatin increases. If it is too large, the copolymer itself has gel properties, so that it is homogeneous with eosinized gelatin. It may be difficult to mix, or the properties of the gel may be imparted to the material itself before crosslinking. In addition, it is necessary to be careful because it may be difficult to control the gelation rate and the degree of swelling of the finally generated gel.

  The ratio of use of the modified gelatin modified with the photosensitive compound and the dimethylamino group-containing compound varies depending on the number of dimethylamino groups of the dimethylamino group-containing compound, but the dimethylamino group-containing compound 0. It is preferable that it is 001-30 weight%. If the amount of photosensitive compound-modified gelatin is larger than this range and the amount of dimethylamino group-containing compound is small, crosslinking may be insufficient. Conversely, if the amount of dimethylamino group-containing compound is large and the amount of photosensitive compound-modified gelatin is small, crosslinking may occur. Later, the properties of the gel may be impaired.

  In the present invention, it is particularly preferable to prepare a visible light curable material by adding 0.05 to 5% by weight of a dimethylamino group-containing compound to an aqueous solution having a modified gelatin concentration of 1.0 to 30.0% by weight. It goes without saying that if this modified gelatin concentration is too high, it takes a long time to obtain an aqueous solution before crosslinking, and if it is too low, it is no longer a gel material.

  The visible light curable material of the present invention preferably has a gelation rate of 10% or more when irradiated with visible light having an illuminance of 10 to 10,000 lx for 1 to 600 seconds. When the gelation rate is less than 10%, the gel cannot sufficiently function as a visible light curable material. Moreover, it is preferable that the degree of swelling when cured into a gel is 350 or less. If the degree of swelling exceeds 100, the strength of the gel will be low, making it unsuitable for uses such as hemostatic agents.

  Since the visible light curable material of the present invention is a viscous liquid, for example, when it is used as a hemostatic agent, it is applied to an application target, and then visible light of about 10 to 10,000 lx, particularly a living body. In the application to the above, to obtain a good hemostatic effect by irradiating with visible light having a relatively low illuminance of about 10 to 100 lx and low influence on the living body for about 1 to 600 seconds and curing it in a gel form. Can do.

  The visible light curable material of the present invention is also useful as various wound healing promoters in addition to hemostatic agents. Here, the wound healing promoting material promotes healing of wounds, such as for closing wounds, for preventing infection from wounds, and for preventing body fluid from oozing out from wounds. For that.

  The wound healing promoter of the present invention can also be used for hemostasis treatment during or after endovascular therapy.

  Conventionally, after endovascular therapy, a large amount of an antithromboplastin agent or the like is generally administered for the purpose of thrombus suppression or dissolution. Therefore, the hemostatic treatment at the site where the sheath is removed is contraindicated with medical therapy that has an effect on the whole body, and there is no other way than to physically stop the blood locally.

As this physical hemostasis, for example,
(1) Assisting hemostasis with a tourniquet to the thigh, while absorbing bleeding from the piercing artery with gauze and continuing to suppress the bleeding site strongly;
(2) Incising the epidermis, skelting the artery and tying it;
Such measures are being taken.

  However, as described in (1) above, it takes about one day to stop the hemostasis with a method that strongly suppresses the pierced part of a large perforated artery, and during that time, the patient is unable to change his / her position and gives great pain. Yes. Also, as described in (2) above, the arterial arteries are surgically treated, and the arteries of a diameter that can be inserted into the catheter are invasive. Even if the side blood flow is obtained, it becomes a factor of poor limb circulation.

  According to the wound healing promoter of the present invention, such conventional problems are solved.

  In order to perform hemostasis treatment during or after endovascular therapy using the wound healing promoter of the present invention, an aqueous solution of the wound healing promoter of the present invention is placed on the outer periphery of the catheter sheath during or after endovascular therapy. And the wound healing promoter component is filled into the interface between the sheath periphery and the subcutaneous tissue. After removal of the catheter, a thin rod or linear body for irradiation with visible light or ultraviolet light is inserted into the sheath or wound after removal of the sheath, and light is irradiated from the rod to crosslink and insolubilize the wound healing promoter component. The insolubilized liquid component is excellent in biocompatibility and functions as a hemostatic material or tissue adhesive, and the hemostatic treatment is completed immediately.

  This wound healing promoter has tissue adhesiveness and is insolubilized in the wound and physically hemostatic. This wound healing promoter does not stop hemostasis by acting on or antagonizing platelets or coagulation factors, but it does not pose any problem even if it gives medical hemostasis.

  In order to supply the wound healing promoting material to the wound and then insolubilize it by irradiation with light, a function capable of locally irradiating the wound healing promoting material and irradiating with light may be incorporated into the catheter sheath. In this case, the outer peripheral surface of the sheath is made of a porous material, and has an injection port different from the catheter introport in the portion exposed to the outside of the body. You may comprise so that it may infiltrate to the outer peripheral surface of the indwelling sheath.

  If the sheath itself has optical transparency, a thin rod-like or linear light emitter may be inserted into the catheter introport for light irradiation.

  Alternatively, after administration of the wound healing promoter aqueous solution from the sheath, a thin rod-like or linear light irradiation body is inserted into the catheter introport, and then the sheath is removed while leaving the light irradiation body on the wound, and then the light irradiation is performed. Light irradiation may be performed through the body to insolubilize the wound healing promoter component, and then the light irradiated body may be removed.

  Hereinafter, the present invention will be described more specifically with reference to synthesis examples, examples and comparative examples.

Synthesis Example 1 Synthesis of Eosinated Vinyl Benzoic Acid Gelatin N-ethyl-N ′-(3-dimethylaminopropyl) carbodiimide, which is a water-soluble carbodiimide, is added to gelatin (molecular weight: 95,000, amino group content: about 37 molecules / molecule). In the presence of (WSC), eosin was synthesized by linking eosin to the amino group of the side chain of gelatin by the following reaction to introduce about 3 eosin per molecule of gelatin.

  The eosinized gelatin is then subjected to an amide bond to the free amino group on the side chain of gelatin in the presence of N-ethyl-N ′-(3-dimethylaminopropyl) carbodiimide (WSC), which is also a water-soluble carbodiimide. As a result, 7 vinyl benzoic acids were introduced per molecule of eosinized gelatin to synthesize eosinized vinyl benzoic acid gelatin.

Synthesis Examples 2 and 3: Synthesis of eosinized cinnamic acid gelatin and eosinized methacrylic acid gelatin In Synthesis Example 1, cinnamic acid (Synthesis Example 2) or methacrylic acid (Synthesis Example 3) was used instead of vinyl benzoic acid in the second stage. Eosinized cinnamic acid gelatin and eosinized methacrylate gelatin into which about 7 cinnamic acids or methacrylic acids were introduced per molecule of gelatin were synthesized in the same manner except that they were used.

Example 1
The gelatin compound of Synthesis Example 1 was made into an aqueous solution having a final concentration of 20% by weight. This aqueous solution was mixed with N, N-dimethylaminopropylacrylamide homopolymer Mn = 50,000 having a final concentration of 2% by weight as a dimethylamino group-containing compound, and then irradiated with visible light having the illuminance shown in Table 1 in Table 1. The gelation rate and swelling degree at this time were examined, and the results are shown in Table 1.

Example 2
Except for using the gelatin compound of Synthesis Example 2, the same procedure as in Example 1 was performed, and visible light was irradiated under the conditions shown in Table 1. The results are shown in Table 1.

Example 3
Except for using the gelatin compound of Synthesis Example 3, the same procedure as in Example 1 was performed, and visible light was irradiated under the conditions shown in Table 1, and the results are shown in Table 1.

Comparative Examples 1-4
In Example 1, visible light was irradiated under the conditions shown in Table 1 in the same manner as in Example 1 except that the gelatin compound was eosinized gelatin. The results are shown in Table 1.

  As shown in Table 1, eosinized vinyl benzoate gelatin, eosinized cinnamate gelatin, and eosinized methacrylate gelatin can swell when irradiated with low-energy visible light for a short time compared to eosinated gelatin. It was possible to suppress the gelation to a high degree and to obtain a gel having a high strength.

Claims (14)

In a visible light curable material that is cured in a gel state by irradiation with visible light, including a compound having a photosensitive group that generates radicals by irradiation with visible light, and a disubstituted amino group-containing compound,
A visible light curable material, wherein the compound having a photosensitive group is gelatin modified with eosin and at least one of cinnamic acid, meth (a) acrylic acid and vinylbenzoic acid.   The visible light curable material according to claim 1, wherein the disubstituted amino group-containing compound is a dimethylamino group-containing compound.   The visible light curable material according to claim 2, wherein the dimethylamino group-containing compound is 1,1,4,7,10,10-hexamethyltrimethylenetetramine.   3. The visible light curable material according to claim 2, wherein the dimethylamino group-containing compound is a copolymer of a vinyl monomer having a dimethylamino group and a water-soluble monomer.   5. The visible light curable material according to claim 4, wherein the dimethylamino group-containing compound is a copolymer of dimethylacrylamide and dimethylaminoethyl methacrylate.   3. The visible light curable material according to claim 2, wherein the dimethylamino group-containing compound is a polymer of a vinyl monomer having a dimethylamino group.   The visible light curable material according to claim 6, wherein the dimethylamino group-containing compound is polydimethylaminopropylacrylamide.   The gelatin according to any one of claims 2 to 7, comprising the dimethylamino group-containing compound and gelatin modified with a compound having a photosensitive group, and the gelatin modified with the dimethylamino group-containing compound and the compound having a photosensitive group. A visible light curable material characterized by gelation by cross-linking formation by recombination reaction between generated radicals.   9. The visible light curable material according to claim 8, comprising 0.001 to 30% by weight of the dimethylamino group-containing compound with respect to gelatin modified with the compound having a photosensitive group.   10. The visible light curable material according to claim 8, wherein a dimethylamino group-containing compound is added to an aqueous solution having a gelatin concentration of 1.0 to 30.0% by weight modified with a compound having a photosensitive group.   The visible light curable material according to any one of claims 1 to 10, wherein a gelation rate when irradiated with visible light having an illuminance of 10 to 10,000 lx for 1 to 600 seconds is 10% or more.   The visible light curable material according to any one of claims 1 to 11, wherein the degree of swelling when cured into a gel is 100 or less.   A wound healing promoter comprising the visible light curable material according to any one of claims 1 to 12.   The wound healing promoter according to claim 13, which is a hemostatic agent.