JPH07265405A - Heparinizing material and its manufacture - Google Patents

Abstract

PURPOSE: To provide a method of readily obtaining an anticoagulant material without using an organic solvent in a production process, wherein haparin is solidified on a surface electrostatically at a high concentration, the heparin is gradually freed in blood by contacting the blood, and further, wherein there is no eluate other than heparin in the anticoagulant. CONSTITUTION: This is to provide a method of producing a material suitable for heparinization, by forming an adsorbed layer on a hydrophobic surface of the material, the adsorption layer containing a polymer of fourth-class ammonium salt monomer having a polymeric functional group and two or three hydrolic carbon chains of carbon number of more than 10 and less than 30. Also, another embodiment provides a heparinizing material wherein an ion pair of the fourth-class ammoniuman salt monomer having a polymeric functional group and a polymer of two or three hydrolic carbon chains of carbon number of more than 10 and less than 30 and the heparin is adsorbed on a surface in contact with blood.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a medical material having anticoagulant properties and a method for producing the same.

[0002]

2. Description of the Related Art When blood comes into contact with an artificial material other than living tissue, the coagulation system of the blood is activated on the surface of the material to cause blood clotting. This problem of blood coagulation has become a major obstacle to the development of therapeutic and diagnostic devices that come into contact with blood, and excellent anticoagulant materials are desired. So far
Materials having various surface structures and various surface treatment methods have been proposed, but at present, heparinized materials are considered to exhibit the best anticoagulant properties.

Heparin is an anticoagulant substance derived from a living body, and is a mucopolysaccharide having a negative charge based on many sulfate groups. The heparinization methods of materials that have been conventionally studied are roughly classified into the following three types.

(1) Simple blending method: a method in which heparin is simply mixed into the material. For example, a material prepared by mixing heparin in an epoxy resin is said to show good anticoagulant properties, but since there is no bond between the polymer matrix and heparin, the material prepared by this method is It has a drawback that heparin easily falls off and the anticoagulant property cannot be maintained for a long time.

(2) Covalent bond method: A method of chemically immobilizing heparin on the surface of a material by covalent bond utilizing a functional group of heparin. However, in such a method, the amount of heparin immobilized is about 0.1 μg / cm ² at the maximum, and the anticoagulant activity of heparin is changed due to the fact that heparin is denatured by the chemical reaction or is not released from the material. Due to insufficient availability, at present no material with satisfactory anticoagulant properties has been obtained by this method.

(3) Ion-bonding method: A method of electrostatically immobilizing heparin on the surface of a material having a positive charge by using the negative charge of heparin. Currently, the best anticoagulant property is obtained. It is said to be the method that can be obtained.

In this ionic bonding method, a positive charge is first introduced on the surface of the material. The positive charge introduction method includes (a) benzalkonium chloride (BC) or tridodecylmethylammonium chloride (TDMAC). A method of introducing a positive charge on the surface of the material by adsorbing a quaternary ammonium salt type surfactant such as
(b) by coating the surface of a material with a water-insoluble polymer compound having a quaternary ammonium group in its main chain or side chain,
A method of introducing a positive charge on the surface of a material is known.
Using the method (a), BC and TDMA in water
Since the hydrophobic group of C is adsorbed on the surface side of the material and the hydrophilic quaternary nitrogen is arranged facing outward, a high-density positive charge can be two-dimensionally introduced to the surface of the material. BC or T
Since DMAC has a low molecular weight, it has a drawback that it is eluted into blood together with heparin. Elution of these cationic surfactants into blood causes problems such as hemolysis and aggregation of plasma proteins. Further, when the method of (b) is used, elution of substances other than heparin is suppressed,
It takes time and effort to synthesize a water-insoluble polymer compound having a quaternary ammonium group in its main chain or side chain. Further, it is not easy to coat the surface of the material with such a compound. As such a coating method, a solvent casting method or the like is generally used. However, since an organic solvent has to be used, there are problems such as residual toxicity and a limited applicable substrate. Further, in order to obtain a water-insoluble polymer compound, it is necessary to increase the ratio of the hydrophobic portion in the molecule and decrease the ratio of the quaternary ammonium group. Therefore, when the material is coated with such a compound using an organic solvent, the quaternary ammonium group is buried in the coating layer, and the positive charge density of the outermost surface layer cannot be increased. Will be insufficient.

[0008]

SUMMARY OF THE INVENTION The object of the present invention is to solve the problems in the conventional method for producing a heparinized material, particularly the ionic bonding method, and electrostatically fix heparin on the surface at a high density. A method for easily obtaining an anticoagulant material that is gradually converted into blood and heparin is gradually released into the blood by contact with blood and has no eluate other than heparin without using an organic solvent in the manufacturing process. To do.

[0009]

As a result of intensive studies to achieve the above object, the inventors of the present invention have found that a hydrophobic functional surface of a material has a polymerizable functional group and two or three carbon atoms of 10 carbon atoms. The present inventors have found that a material suitable for heparinization can be obtained by forming an adsorption layer containing a polymer of a quaternary ammonium salt monomer having a hydrocarbon chain of less than 30 and completed the present invention.

That is, according to the present invention, a quaternary ammonium salt monomer having a polymerizable functional group and two or three hydrocarbon chains having 10 or more and less than 30 carbon atoms is adsorbed on the hydrophobic surface of the material in water. The present invention relates to a method for producing a material suitable for heparinization, which is characterized by being polymerized later, and a material suitable for heparinization produced by such a method.
Furthermore, another embodiment of the present invention is that the ion pair between a polymer of a quaternary ammonium salt monomer having a polymerizable functional group and two or three hydrocarbon chains having 10 or more and less than 30 carbon atoms and heparin is The present invention relates to a heparinized material that is adsorbed on a surface that comes into contact with blood. Still another aspect of the present invention is to adsorb a quaternary ammonium salt monomer having a polymerizable functional group and two or three hydrocarbon chains having 10 or more and less than 30 carbon atoms to the hydrophobic surface of the material in water. The present invention relates to a method for producing a heparinized material, characterized in that heparin is electrostatically bound to the surface by contacting with an aqueous solution of heparin after the polymerization.

Further, in the present invention, after forming an ion pair of heparin with a quaternary ammonium salt monomer having a polymerizable functional group and two or three hydrocarbon chains having 10 or more and less than 30 carbon atoms, It relates to a method for producing a heparinized material, which comprises adsorbing the ion pair to a hydrophobic surface of the material in water and then polymerizing the monomer.

The quaternary ammonium salt monomer used in the present invention is required to have at least one polymerizable functional group and two or three hydrocarbon chains having 10 or more and less than 30 carbon atoms in its molecule. is there. Where carbon number 1
The hydrocarbon chain of 0 or more and less than 30 is necessary for adsorbing the quaternary ammonium salt monomer on the hydrophobic surface of the material in the aqueous phase, and further, the number of such hydrocarbon chain is 2 or 3 in 1 molecule. By being present, the hydrophobic hydrocarbon groups of the quaternary ammonium salt monomer are adsorbed on the material surface side on the hydrophobic surface of the material, and the hydrophilic quaternary nitrogen is densely arranged facing the aqueous phase side. Therefore, a high density positive charge can be two-dimensionally introduced into the hydrophobic surface of the material. In order to impart such a property to the monomer, the hydrocarbon group must have 10 or more and less than 30 carbon atoms, and more preferably 14 or more and less than 23 carbon atoms.
The structure of the hydrocarbon chain is preferably a structure having no branching for a dense arrangement, but it may have an unsaturated bond. Preferred examples of such a hydrocarbon chain include alkyl groups such as tetradecyl, hexadecyl and octadecyl, and acyl groups such as stearoyl and oleoyl. These long chain hydrocarbon groups may be directly bonded to the quaternary nitrogen, or may be indirectly bonded to the quaternary nitrogen as a glycerin fatty acid ester or the like. On the other hand, the polymerizable functional group in the quaternary ammonium salt monomer used in the present invention is necessary for polymerizing the quaternary ammonium salt monomer adsorbed on the hydrophobic surface of the material to prevent elution into blood. Preferable examples of the polymerizable functional group include vinyl group, allyl group, acryl group, methacryl group and the like. The quaternary ammonium salt monomer according to the present invention may be polymerized alone or may be copolymerized with another polymerizable monomer. As the polymerization method, a usual radical polymerization initiator may be used, or the polymerization may be carried out by irradiating with an electron beam or γ-ray.

The quaternary ammonium salt monomer used in the present invention has an extremely low solubility in water in the monomolecular state, but it is uniformly dispersed in water by forming a fine molecular aggregate such as a micelle or a bilayer vesicle. It can be dispersed. When the surface of a material having a hydrophobic property is arranged in this dispersion, the quaternary ammonium salt monomer is spontaneously adsorbed on the hydrophobic surface of the material by hydrophobic interaction. The concentration of the quaternary ammonium salt monomer that can be present in the dispersion depends on the surface area of the material,
Usually, it is in the range of 0.001 to 1% by weight. Next, after deoxidizing the dispersion by nitrogen bubbling or the like, a state in which a polymerization initiator is added or electron rays or γ rays are irradiated to adsorb the quaternary ammonium salt monomer on the hydrophobic surface of the material Polymerize as it is. In this case, polymerization also occurs in the micelles or bilayer vesicles remaining in the dispersion. Further, the material having the quaternary ammonium liquid monomer adsorbed on the surface is taken out from the dispersion liquid, and is irradiated with an electron beam or γ-ray in an atmosphere of an inert gas such as nitrogen to remove only the quaternary ammonium salt monomer adsorbed on the material surface It can also be polymerized.

The materials that can be used in the present invention are those commonly known as raw materials for producing heparinized materials, such as synthetic polymeric materials, natural rubber,
Metals and the like can be used, but as medical materials,
From the aspects of moldability, safety and economy, polypropylene, polyethylene, polyvinyl chloride, polyester,
Hydrophobic polymeric materials such as polyurethane, polystyrene, polycarbonate, porsulfone, polymethylmethacrylate, etc. are preferred. The shape of the hydrophobic surface of such a material is not particularly limited and may be flat or curved.

As described above, on the surface of the material on which the adsorption layer containing the polymer of the quaternary ammonium salt monomer is formed,
Heparin can be easily immobilized by the heparinization method described below.

In the heparinization method according to the present invention, as described above, a quaternary ammonium salt monomer having a polymerizable functional group and two or three hydrocarbon chains having 10 or more and less than 30 carbon atoms is prepared in water. After being adsorbed on the hydrophobic surface of the material and polymerized, the material is contacted with an aqueous solution of heparin to form an ion pair between the quaternary ammonium nitrogen in the polymer and heparin, thereby causing heparin to surface. Fixed to. At this time, the higher the concentration of heparin in the aqueous solution of heparin, the higher the rate and amount of adsorption of heparin on the surface of the material, which is desirable.

The heparinized material according to the present invention forms an ion pair between heparin and a quaternary ammonium salt monomer having a polymerizable functional group and two or three hydrocarbon chains having 10 or more and less than 30 carbon atoms. It can also be produced by adsorbing the ion pair to the hydrophobic surface of the material in water and then polymerizing the monomer, and such a method is also included in one embodiment of the present invention.

In such a method, heparin alone is completely dissolved in water, but when the quaternary ammonium salt monomer according to the present invention is allowed to coexist at a constant ratio, the sulfate group of heparin and 4 of the monomer are dissolved. Ion pairs are formed with the quaternary ammonium nitrogen and the ion pair complex is totally water insoluble. Here, the ratio of the quaternary ammonium salt monomer and heparin is preferably in the range of 0.5 to 3 parts by weight with respect to 1 part by weight of heparin. If the relative amount of the quaternary ammonium salt monomer is less than this range, the ion-pair complex as a whole is unlikely to be water-insoluble, and if it exceeds this range, the amount of the quaternary ammonium salt monomer that does not bind to heparin increases, which is not desirable. When the surface of a material having a hydrophobic property is arranged in the thus prepared ion-pair complex dispersion, the quaternary ammonium salt monomer portion in the complex spontaneously interacts with the surface of the material by hydrophobic interaction. Adsorb to. At this time, since the ion pair is still formed, heparin is simultaneously adsorbed on the surface of the material. The concentration of ion-pair complex that can be present in the dispersion in such a method depends on the surface area of the material, but is usually 0.0
It is in the range of 01 to 0.1% by weight. Next, the dispersion is deoxygenated by nitrogen bubbling or the like, and then a polymerization initiator is added or an electron beam or γ-ray is irradiated to leave the ion pair complex adsorbed on the surface of the material. , Polymerize the quaternary ammonium salt monomer in the ion pair complex. In the method of this aspect, the arrangement of the quaternary ammonium salt monomer adsorbed on the surface of the material is likely to be in a sparse packing state as compared with the first method, and when the distance between the polymerizable functional groups is increased, the polymerization is performed. In order to avoid such a problem, it is possible to add another water-soluble monomer such as hydroxyethyl methacrylate (HEMA) to the dispersion liquid to copolymerize it with the quaternary ammonium salt monomer. it can. Further, in such a method, polymerization also occurs in the ion-pair complex remaining in the dispersion,
In the same manner as described above, the material having the ion-pair complex adsorbed on the surface was taken out from the dispersion liquid, irradiated with an electron beam or γ-ray under an atmosphere of an inert gas such as nitrogen, and adsorbed on the surface of the material. It is also possible to polymerize only the quaternary ammonium salt monomer in the ion pair complex.

By immersing the heparinized material obtained by such a method in a high-concentration heparin aqueous solution, the amount of heparin bound to the surface can be further increased.

Hereinafter, the present invention will be described more specifically by showing examples.

[0021]

【Example】

(Example 1 and Comparative Example 1) (Synthesis of Quaternary Ammonium Salt Monomer) 10 g of dioleylamine (Amine 2-OLR manufactured by NOF CORPORATION) was dissolved in 20 ml of chloroform, and 10 g of allyl bromide and 5 g of sodium carbonate were dissolved. In addition, the reaction was carried out by stirring at room temperature overnight. After filtering the reaction product, the solvent was distilled off under reduced pressure and diallyl (dioleyl) ammonium bromide (D
13 g of ADOA) was obtained.

(Formation of Adsorption Layer Containing Polymer of Quaternary Ammonium Salt Monomer) DADOA 1 obtained as described above
g was put in 1000 ml of distilled water and dispersed by ultrasonic irradiation. Polyester mesh cut into 2 × 5 cm strips (manufactured by NBC Industry Co., Ltd., T-N0
250 sheets of 80S, fiber diameter 75 μm, pitch 300 μm) were dipped in the above DADOA dispersion to adsorb the DADOA monomer on the polyester mesh surface. After deoxygenating the dispersion by bubbling nitrogen through it, 176 μl of 10 wt% ammonium persulfate (APS) aqueous solution
And 18 μl of N, N, N ′, N′-tetramethylethylenediamine (TEMED) were added and shaken under nitrogen at room temperature overnight to polymerize DADOA. The polyester mesh was taken out from the dispersion and thoroughly washed with distilled water. A material was obtained in which an adsorption layer containing a polymer of DADOA was formed on a hydrophobic surface.

(Heparinization of material) DA obtained above
A polyester mesh having a DOA polymer on its surface,
A heparinized polyester mesh was obtained by immersing it in a 1 wt% aqueous solution of heparin (manufactured by Wako Pure Chemical Industries, Ltd.) overnight at room temperature to electrostatically bind heparin and thoroughly washing it with distilled water.

2 pieces of this heparinized polyester mesh
Heparin was eluted by immersing it in a saline solution of M, desalted, and then heparin was quantified by the toluidine blue method. The heparin binding amount on the surface of the heparinized polyester mesh was determined to be 0.2 μg / cm ² . Further, when an eluate test was conducted using potassium permanganate, no eluate other than heparin was found.

(Anticoagulant test) The heparinized polyester mesh obtained as described above was applied to a vinyl chloride blood circuit (line tube: inner diameter 3 mm, outer diameter 5 mm, length 15).
2 cm inside the chamber (inner diameter 13 mm, outer diameter 15 m
m, length 8 cm), thoroughly washed and filled with physiological saline, and then used to perform an operation to bypass the femoral artery-femoral vein of a beagle adult dog (AV shunt method) . As a comparative example, the same operation was performed using untreated polyester mesh. In the circuit using the untreated polyester mesh, coagulation occurred in the mesh about 30 minutes after the circulation of blood was started, and the blood flow in the circuit was stopped. On the other hand, in the circuit using the heparinized polyester mesh, the blood flow in the circuit stopped in about 80 minutes. A delay in thrombus formation of about 50 minutes was confirmed. This confirmed the effective anticoagulant properties of the heparinized polyester mesh.

(Second Embodiment) DAD is carried out in the same manner as in the first embodiment.
After adsorbing the OA monomer on the surface of the polyester mesh, the polyester mesh was taken out of the dispersion liquid and irradiated with 2 Mrad γ-rays in a nitrogen atmosphere to polymerize DADOA. After the polyester mesh was washed with distilled water and heparinized in the same manner as in Example 1, the same heparin binding amount as in Example 2 was obtained. When the same anticoagulant test as in Example 1 was conducted using the obtained heparinized material, the same result was shown, and the effective anticoagulant property of the heparinized polyester mesh was confirmed.

(Example 3) (Heparinization by a method according to another embodiment of the present invention) DA
Aqueous dispersion 100 containing 0.006% by weight of DOA, 0.002% by weight of heparin, 0.5% by weight of HEMA
After immersing the same polyester mesh as in Example 1 in 0 ml, the same polymerization reaction as in Example 1 was performed using the redox initiator system of APS and TEMED. After thoroughly washing this polyester mesh with distilled water, the amount of heparin binding was determined in the same manner as in Example 1 and found to be 1.5.
It was μg / cm ² . This polyester mesh 1
The overnight heparin binding increased the amount of heparin binding to 2.2 μg / cm ² . Further, when an eluate test was conducted in the same manner as in Example 1, no eluate other than heparin was observed. When an anticoagulant test was conducted in the same manner as in Example 1, effective anticoagulant properties were confirmed.

(Example 4 and Comparative Example 2) The same dispersion liquid as in Example 3 was circulated in a vinyl chloride tube (inner diameter 2 mm, outer diameter 4 mm, length 80 cm), and then in the same manner as in Example 3. Polymerization reaction was carried out to obtain a heparinized tube.
After thoroughly washing this heparinized tube with distilled water,
Using this, an anticoagulant test was conducted in the same manner as in Example 1. Further, as a comparative example, the same test was performed using an untreated tube. Blood was allowed to flow into each tube for 1 hour and 3 hours, then the inner surface of the tube was washed with physiological saline, the formed thrombus was fixed, and the inner surface of the tube was observed with an electron microscope. In the untreated tube, many microthrombus were observed also on the inner surface of the tube in which blood was flowed for 1 hour, but in the heparinized tube, no thrombus was observed in the tube in which blood was flowed for 3 hours. The effective anticoagulant properties of the heparinized tube were confirmed.

[0029]

As described above in detail, the heparinized material according to the present invention has an extremely high anticoagulant property because electrostatically dense heparin is bound to the surface thereof. Moreover, since there is no eluate other than heparin, it is highly safe. In addition, the heparinization method according to the present invention is simpler in operation than various conventional heparinization methods, and the long-chain hydrocarbon group in the quaternary ammonium salt monomer has a hydrophobic surface of the material due to hydrophobic interaction. Since the material surface is coated by utilizing the property that it is adsorbed on, it can be applied to a wide range of materials without using an organic solvent.

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Masato Mikami 2-5-6-203 Ohsaw, Fujisawa City, Kanagawa Prefecture (72) Inventor Manabu Yamazaki 5-37-405 Tsurumaki Kita 2-chome, Hadano City, Kanagawa Prefecture (72) Inventor Yasushi Kubota 3-21-24 Higashi, Kunitachi, Tokyo

Claims (5)

[Claims] 1. An adsorption layer containing a polymer of a quaternary ammonium salt monomer having a polymerizable functional group and two or three hydrocarbon chains having 10 or more and less than 30 carbon atoms is formed on the hydrophobic surface of the material. A material suitable for heparinization, which is characterized by 2. Polymerizing after adsorbing a quaternary ammonium salt monomer having a polymerizable functional group and two or three hydrocarbon chains having 10 or more and less than 30 carbon atoms in water on the hydrophobic surface of the material. The method for producing a material suitable for heparinization according to claim 1. 3. An ion pair of heparin and a polymer of a quaternary ammonium salt monomer having a polymerizable functional group and two or three hydrocarbon chains having 10 to less than 30 carbon atoms and heparin on the surface in contact with blood. A heparinized material characterized by being adsorbed. 4. A quaternary ammonium salt monomer having a polymerizable functional group and two or three hydrocarbon chains having 10 or more and less than 30 carbon atoms is adsorbed on the hydrophobic surface of the material in water to be polymerized, and then heparin. The method for producing a heparinized material according to claim 3, wherein heparin is electrostatically bound to the surface by contacting with the aqueous solution. 5. After forming an ion pair of heparin and a quaternary ammonium salt monomer having a polymerizable functional group and two or three hydrocarbon chains having 10 or more and less than 30 carbon atoms,
The method for producing a heparinized material according to claim 3, wherein the ion pair is adsorbed on a hydrophobic surface of the material in water, and then the monomer is polymerized.