JPH0975445A - Antithrombic agent and medical base material provided with antithrombic function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antithrombic agent soluble in various organic solvents and ensuring high safety, and a medical base material provided with the antithrombic function for stability over a long period via a simple method by using the anticoagulant action of heparin. SOLUTION: This base material has a surface to hold a combined material formed out of a compound containing an amidino group and heparin via an ion bond.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an antithrombotic agent and an antithrombotic agent for medical use.

[0002]

2. Description of the Related Art When blood comes into contact with a foreign substance other than vascular endothelial cells, platelets adhere to the surface of the foreign substance, followed by blood coagulation and thrombus. This thrombus formation may cause complications such as blood flow stoppage and sepsis when using a medical device such as a catheter, a blood circuit, an artificial dialyzer, or an artificial heart-lung machine.

Therefore, in order to prevent thrombus formation on the blood contact surface of the medical device, blood is made non-coagulant by adding an anticoagulant, or a material that does not form a thrombus, that is, an antithrombotic material, A method of coating the blood contact surface is conceivable. Currently, when using medical devices such as artificial dialysis and cardiopulmonary bypass, heparin, which is an anticoagulant, is added to blood to prevent blood coagulation, but the use of a large amount of heparin reduces thrombocytopenia during artificial dialysis. As a side effect such as illness, there is a problem that it is difficult to stop bleeding after surgery in an artificial heart-lung machine.

Therefore, the development of a material that does not form a thrombus, that is, an antithrombogenic material, has been earnestly pursued by various methods. Among them, the method of forming a thin layer of heparin on the blood contact surface of a medical device is the most effective. Many technologies have been developed from the idea that they exist. Gott et al. Have shown on the surface of plastics graphite and benzalkonium chloride: the general formula [C ₆ H ₅ CH ₂ N (CH ₃ ) ₂ R] Cl (R is C ₈ H _17-
C ₁₈ H ₃₇ alkyl mixture). We developed a technique to form a thin layer of heparin on the plastic surface by immersing it in an aqueous solution of heparin and causing an ionic bond between benzalkonium chloride and heparin (V.
L. Gott et al., Ann. NYAcad. Sci., 146, 21 (1968)). The antithrombotic material treated in this way is called GBH, which is an acronym for the reagent, and exhibits excellent antithrombotic properties in vivo, but has the drawback that it gradually dissolves when it comes into contact with blood. Was there. It has been reported that GBH material placed intravascularly in dogs has lost 90% of its original heparin content after 2 months.

Then, as an improved method, a method of ion-bonding heparin using tridodecylmethylammonium chloride (TDMAC), which is more hydrophobic than benzalkonium chloride and has a high retention property on the plastic surface (GAGrode et al., Trans. .Am.Soc.Artif.Organ
s, 15,1 (1969)) or benzalkonium chloride: the alkyl chain R of the general formula [C ₆ H ₅ CH ₂ N (CH ₃ ) ₂ R] Cl is limited to C ₁₆ H ₃₃ -C ₁₈ H ₃₇ , A method of increasing the hydrophobicity to achieve non-thrombogenic formation for a long period of time and reduction of heparin elution amount (Japanese Patent Publication No. 36267/1990) has been developed. However, all the compounds are highly toxic as shown by the fact that they are used as fungicides, disinfectants, preservatives, etc., and there has been a concern about the safety problem when they are dissolved in blood.

[0006]

SUMMARY OF THE INVENTION Therefore, the object of the present invention is to solve the above-mentioned problems of the prior art, and to use the anticoagulant action of heparin to impart an antithrombotic property which maintains a stable antithrombotic property for a long period of time. An object is to provide a medical base material having an agent and an antithrombotic property.

[0007]

The above problems can be solved by the following means. (1) An antithrombotic agent, which is a complex of a compound having an amidino group in one molecule and heparin. (2) The antithrombotic agent according to (1), wherein the compound having an amidino group in one molecule is an arginine derivative. (3) The arginine derivative is N-alkylacyl-L-
The antithrombotic agent according to (2), which is an arginine ester. (4) The antithrombogenic agent according to (3), wherein the N-alkylacyl-L-arginine ester is N-coconut oil fatty acid acyl-L-arginine ethyl. (5) A medical base material, characterized in that the antithrombogenic agent according to (1) to (4) is retained on the surface of the base material.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below, but the present invention is not limited thereto.

The compound used in the present invention is not particularly limited as long as it has one amidino group in one molecule and forms a complex with heparin, and the complex is soluble in an organic solvent. Not done. Preferably, a naturally occurring compound or its derivative is used. Here, the complex refers to a complex formed by an ionic bond between an amidino group and a sulfate group in the heparin molecule. The reason why the ionic conjugate is preferable as the complex is that the sulfate group in the heparin molecule expressing antithrombotic property can be maintained as it is and the complex can be easily produced.

Preferred examples of the compound include an arginine derivative, a benzamidine derivative, an aminobenzamidine derivative, a phenylguanidine derivative, a guanitidine sulfate derivative, and the like, more preferably, a peptide containing arginine and an ester of arginine. Examples thereof include naturally-derived compounds such as derivatives and amide derivatives, and arginine derivatives composed of the derivatives.
Arginine derivatives include (2R, 4R) -4-ethyl-1- [N2- (3-methyl-1,2,3,4-tetrahydro-8-quinolinesulfonyl)-
L-arginyl] -2-piperidinecarboxylic acid monohydrate, dansylarginine N- (3-ethyl-1,5-pentanediyl) amide, gabexate mesylate and 2-6-amidino-nap 4-
Guanidinobenzoate dimethyl sulfate and the like are also included, but particularly preferably N-alkylacyl-L-
It is an arginine ester. More preferred is N-coconut oil fatty acid acyl-L-arginine ethyl.

The compound is a naturally-occurring compound or its derivative, and is generally less toxic than quaternary ammonium compounds such as benzalkonium chloride and tridodecylmethylammonium chloride used in the conventional complex with heparin. Low. In addition, N-alkylacyl-L-
Arginine ester consists of natural amino acid arginine, and N-coconut oil fatty acid acyl-L-arginine ethyl is an ester compound of natural amino acid arginine and fatty acid extracted from natural palm fruit,
Even if it is eluted in the blood, the degradation products of the ester compound are natural amino acids and fatty acids, which are sufficiently safe compounds. In fact, the LD ₅₀ value (the amount of drug that kills half of many animals belonging to the same population), which is the basis for comparing drug risks, is benzalkonium chloride: 455 mg / Kg (rat), tridodecylmethyl. Ammonium chloride: 500-600 mg / K
g (rat), N-coconut oil fatty acid acyl-L-arginine ethyl: 8.2 g / Kg (rat), N
-The coconut oil fatty acid acyl-L-arginine ethyl is a compound having sufficiently high safety as compared with the conventional quaternary ammonium compound.

The heparin used in the present invention is the most commonly clinically used anticoagulant, and is a kind of polysaccharide containing an ester-bonded sulfate group. In general, heparin has its sulfate group neutralized and stabilized as a metal salt of sodium, lithium, calcium or the like.

The complex of a compound having an amidino group and heparin in the present invention has an aqueous solution of a compound having an amidino group or an aqueous solution of alcohol added dropwise to an aqueous solution of a heparin metal salt and an aqueous solution of alcohol, or has an amidino group. This is achieved by dropping an aqueous solution of a heparin metal salt or an aqueous solution of an alcohol into an aqueous solution of a compound or an aqueous solution of an alcohol, and a complex is formed by an ionic bond between an amidino group and a sulfate group in a heparin molecule. Since the obtained complex becomes insoluble in water and an aqueous solution containing alcohol and forms a precipitate, the precipitate can be collected by filtration or centrifugation, washed with water and dried to obtain only the complex with high purity. Here, the alcohol-containing aqueous solution refers to an aqueous solution of a lower alcohol such as methanol, ethanol and isopropanol, and the alcohol concentration is preferably low. Heparin is not dissolved in an aqueous solution having a high alcohol concentration, and the complex is dissolved in an alcohol-containing aqueous solution to form no precipitate, which is not preferable.

The method of holding the composite on the surface of the substrate in the present invention is not limited, and a method of dissolving the composite in various organic solvents and coating the surface of the substrate is exemplified. The application method may be, but is not limited to, dipping, spraying, spin coating, or the like. At this time, the composite may be impregnated into the surface layer of the base material or may form a coating film on the surface of the base material.

Here, the organic solvent for dissolving the complex is not particularly limited, and lower alcohols such as methanol, ethanol, isopropanol, n-butanol, acetone,
Ketones such as methyl ethyl ketone, diethyl ether,
It may be selected from ethers such as tetrahydrofuran and dioxane, aprotic polar solvents such as dimethyl sulfoxide, dimethylformamide and N-methylpyrrolidone, halogenated hydrocarbons such as carbon tetrachloride, chloroform, tetrachloroethane, dichloromethane and freon. However, lower alcohols such as methanol, ethanol, isopropanol and n-butanol, or halogenated hydrocarbons such as chloroform and freon are preferably used.

The medical base material used in the present invention includes, in addition to medical instruments in the form of products actually used, parts and materials of medical instruments used in contact with blood or living tissue, The shape and material of the device are not particularly limited. A medical substrate made of metal, ceramic, organic polymer material, carbon, a composite material thereof, or the like may be used, and a medical device molded or assembled from a plurality of materials may be used. In particular, organic polymer materials such as polyolefin, modified polyolefin, polyether, polyurethane, polyamide, polyimide, polyester and their copolymers are preferable.

The medical device produced from the medical base material of the present invention is not particularly limited as long as it is used in contact with blood or living tissue and requires anticoagulant activity. Preferable examples include implantable artificial blood vessels and therapeutic instruments, extracorporeal circulation artificial organs, catheters / guidewires used in vivo, and members thereof. Preferably, it is a medical device that is used for a long period of time in a living body or a medical device that is used for a long period of time due to ex vivo extracorporeal circulation.

[0018]

The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

Example 1 4.3 g of heparin sodium salt was dissolved in 50 ml of distilled water. While stirring the aqueous solution, N-coconut oil fatty acid acyl-L-arginine ethyl DL-pyrrolidone carboxylate (manufactured by Ajinomoto Co., Inc.) 1
100 ml of an aqueous solution containing 0 g was added dropwise. As a result, a complex of heparin and N-coconut oil fatty acid acyl-L-arginine ethyl was precipitated as a water insoluble matter. 2 of this precipitate
The precipitate and the supernatant were separated by centrifugation at 000 rpm for 20 minutes. The supernatant was discarded, distilled water was newly added to this precipitate, the mixture was stirred, and the operation of centrifuging was repeated twice to wash the precipitate. This was dried under reduced pressure at room temperature to obtain 5.7 g of a complex. Infrared absorption spectrum by ATR method of this complex is the characteristic absorption of the sulfonic acid groups derived from heparin 1689-1471cm ^-1, N to 2150-2100Cm ^-1
-Specific absorption of amidino groups derived from coconut oil fatty acid acyl-L-arginine ethyl was observed.

Example 2 4.3 g of heparin sodium salt was dissolved in 50 ml of distilled water. While stirring the aqueous solution, (2R, 4R) -4-ethyl-1- [N2- (3-methyl-1,2,3,4-tetrahydro-8-quinolinesulfonyl) -L-arginyl] -2
-Piperidinecarboxylic acid monohydrate (synthesis method is R. Kikum
oto, Y.Tamao, T.Tezuka, S.Tonoura, H.Hara, K.Ninomiya,
A. Hijikata and S. Okamoto, Biochemistry, 23 , 85 (1984)
100 ml of an ethanol-water mixed solution (volume ratio 2: 8) containing 10 g of the same was added dropwise. With this heparin
(2R, 4R) -4-Ethyl-1- [N2- (3-methyl-1,2,3,4-tetrahydro-8-quinolinesulfonyl) -L-arginyl] -2-piperidinecarboxylic acid monohydrate A complex of substances precipitated as a water insoluble matter. This precipitate was centrifuged at 2000 rpm for 20 minutes to separate the precipitate from the supernatant. The supernatant was discarded, distilled water was newly added to this precipitate, the mixture was stirred, and the operation of centrifuging was repeated twice to wash the precipitate. This was dried under reduced pressure at room temperature to obtain 5.7 g of a complex. ATR of this complex
Infrared spectrum by the method is 1689-1471 cm
^-1 has a characteristic absorption of the sulfonic acid group derived from heparin by 215
0-2100 cm ^-1 (2R, 4R) -4-ethyl-1- [N2- (3-methyl-1,2,3,4-tetrahydro-8-quinolinesulfonyl) -L-
Characteristic absorption of the amidino group derived from arginyl] -2-piperidinecarboxylic acid monohydrate was observed.

(Example 3) Composite 1 produced in Example 1
50 parts by weight of ethanol was added to parts by weight and stirred to dissolve. This solution was applied to the outer surface of a hollow fiber for heart-lung machine (made of polypropylene) and dried.

An artificial heart-lung machine (effective membrane area: 0.8 m ² ) produced using this hollow fiber was used for extracorporeal circulation between the carotid artery and vein (blood flow rate: 500 ml / mim) using a pig weighing 52 kg. At this time, heparin 100 (IU / K
g), 10 (IU / Kg / Hr.) was continuously administered during circulation. No thrombus was observed even after using this hollow fiber for heart-lung machine for 6 hours.

(Example 4) Composite 1 produced in Example 2
50 parts by weight of methanol was added to parts by weight, and the mixture was stirred and dissolved. This solution was applied to the inner surface of a blood circuit tube for artificial heart lung (made of vinyl chloride, inner diameter 8 mm, length 1 m) and dried. Into the blood circuit tube, 10 ml of human blood collected without using an anticoagulant was placed. After being left at room temperature for 24 hours, blood did not coagulate and thrombus was not formed.

(Comparative Example) An artificial heart-lung machine (effective membrane area 0.8 m ² ) made of hollow fiber prepared without using the antithrombotic agent of the present invention was used in the same manner as in Example 3 using a pig weighing 54 kg. (Heparin was continuously administered at 100 (IU / Kg) before circulation and 10 (IU / Kg / Hr.) During circulation) When used for extracorporeal circulation between the carotid artery and vein, thrombus was observed after 4 hours of use. It was observed and showed an increase in circulation pressure associated with thrombus formation.

[0025]

The antithrombogenic agent of the present invention can be dissolved in various organic solvents by forming a complex of a compound having an amidino group and heparin. Further, by applying the antithrombotic agent of the present invention to the surface of a desired medical substrate, it is possible to easily obtain a medical device imparting antithrombotic property for a long period of time. Even when applied to a circuit, artificial heart, artificial heart-lung machine, dialyzer, catheter, etc. for a long period of time, it is possible to provide a high-quality medical device with little damage to blood and living tissues.

Claims (5)

[Claims] 1. An antithrombotic agent, which is a complex of a compound having an amidino group in one molecule and heparin. 2. The antithrombotic agent according to claim 1, wherein the compound having an amidino group in one molecule is an arginine derivative. 3. The antithrombotic agent according to claim 2, wherein the arginine derivative is N-alkylacyl-L-arginine ester. 4. The antithrombogenic agent according to claim 3, wherein the N-alkylacyl-L-arginine ester is N-coconut oil fatty acid acyl-L-arginine ethyl. 5. A medical base material, characterized in that the antithrombogenic agent according to any one of claims 1 to 4 is retained on the surface of the base material.