JPH0374111B2 - - Google Patents

Description

[Detailed description of the invention]

Industrial Application Field The present invention is hard and stiff at the time of insertion, and after insertion,
The present invention relates to an intravascular indwelling catheter, preferably an intravascular indwelling catheter for high-calorie infusion, made of a polyurethane-based polymer material that is softened by blood water or blood components and does not damage blood vessels. BACKGROUND ART Conventionally, soft catheters have been used as intravascular indwelling catheters. In the insertion method, a guide wire is inserted prior to insertion, then a catheter is passed through the guide wire, and the guide wire is removed. In this case, since the catheter is soft, there is no danger of damaging the vascular endothelium, but on the other hand, extra operations are required, and there are many opportunities for bacterial invasion due to the extra operations. On the other hand, when using a hard catheter, the insertion into the living body is very smooth, but when it is inserted into the blood vessel or left in the blood vessel, it may damage the vascular endothelium and cause vasculitis or blood column formation. The disadvantage is that it is easy to do so. Problems to be Solved by the Invention The present inventors have come up with the idea that the above problems can be solved if there is a catheter that is hard and stiff before insertion, but quickly softens after insertion into the living body, and has conducted extensive research. As a result, the catheter molding material, polyurethane, which has been given hydrophilic properties by appropriately designing the molecular composition, has been shown to have a hydrophilic property after the catheter is inserted into the living body.
They quickly discovered that it could be made softer and completed the present invention. Means for Solving the Problems The catheter according to the present invention is used, for example, as an intravascular indwelling catheter for high-calorie infusion,
The catheter is characterized in that it is molded using a hydrophilic polyurethane polymer material. Methods for imparting hydrophilicity to polyurethane include: (1) During the synthesis of polyurethane, relatively hydrophilic compounds such as HO-(CH ₂ ) _o -OH (n = 2 to 4) are used as a prepolymer and as a "soft segment" of the polymer. 4, which is commonly used as a "hard segment"
Instead of 4'-diphenylmethane diisocyanate (MDI), a less hydrophobic
4, in which the benzene nucleus of the MDI is saturated with hydrogen,
4′-dicyclohexanylmethane diisocyanate (HMDI); (2) polymer blending of a more hydrophilic and highly compatible polyurethane with ordinary hydrophobic polyurethane; (3) Swelling ordinary hydrophobic polyurethane with a partially hydrophilic monomer that is compatible with it,
Examples include methods such as polymerization using radiation, plasma, radicals, and other possible reaction methods. Catheters molded from polymers or polymer compositions obtained by these methods have hydrophilic properties due to the molecular structure and soften upon contact with water. Examples The present invention will be specifically described below with reference to Examples and Comparative Examples. Comparative Examples 1, 2, and 3 The softening properties of commercially available catheters made of MDI-polyol polyurethane (Comparative Example 1), polysiloxane (Comparative Example 2), and PVC silicone coat (Comparative Example 3) were measured. . The measurement method is 20% as a fat-soluble liquid similar to blood.
Using an ethanol/water mixture, it was immersed at 25°C for 30 minutes, and the modulus at a deformation of 50% before and after immersion was measured at a tensile speed of 20 mm/min, 25°C, and 60% relative humidity. type of catheter,
The dimensions are shown in Table 1, and the measurement and evaluation results are shown in Table 2.

【table】

[Table] As can be seen from Table 2, Comparative Example 1 hardly softens even when immersed in the liquid, and Comparative Example 2 also has the same degree of softening, but is inherently extremely soft and therefore has poor insertability.
Comparative Example 3 also showed almost no softening. The antithrombotic properties were evaluated by implantation into rabbit jugular veins for 2 days. Example 1 OH-[-( _CH2 ) ₄ -O-] _o -H was used as the "soft segment" of a polyurethane prepolymer, and 4,4'-dicyclohexanylmethane diisocyanate was used as the "hard segment". A polyurethane elastomer with a weight average molecular weight of 160,000 was obtained by polycondensation reaction using butanediol as a chain extender. Using this, outer diameter 1.90mm, inner diameter 1.40mm,
A catheter with a cross-sectional area of 1.30 ^mm2 was fabricated. Example 2 As a polyurethane prepolymer, 4,4'-dicyclohexanylmethane diisocyanate was used as the "hard segment" and HO-[-(C ₂ H ₄ O) _n (C ₃ H _6O ) _o- ] _p -H (average molecular weight 2000, propylene oxide 50%) was used to polymerize hydrophilic polyurethane using butanediol as a chain extender. This polymer was added to a conventional hydrophobic polyurethane so that the polymer content was 50% by weight to make a polymer blend, and a catheter of the same size as in Example 1 was made from this polymer blend. The catheters of Examples 1 and 2 were tested for softening properties and other properties in the same manner as in the comparative example. The results are shown in Table 3 below.

[Table] As shown in Table 3, the catheter according to the present invention exhibits excellent softening properties and also has excellent catheter insertability. Example 3 The physical properties of the catheters of Example 1 and Comparative Example 1 were further measured. Measurement items and test results are shown in Table 4.

[Table] Test conditions Catheter strength and adhesive strength with the catheter base: Autograph (constant speed 200 mm/min, 20°C) Next, the temperature dependence of catheter hardness and the time dependence in water were measured in Example 1 and Comparative Example. 1 was measured. The measurement method was a torsion test in water using a Gehman tester. Regarding time dependence in water, the water temperature was 36.8°C, which is equivalent to body temperature. The results are shown in Figures 1 and 2, respectively. As can be seen from Table 4, the catheter according to the present invention shows excellent results in terms of practicality such as strength, elongation, and adhesive strength with the catheter base.
As shown in FIGS. 2 and 2, it is hard before being inserted into the blood vessel, but quickly softens after insertion, and is understood to be easy to insert and to be safe during insertion and indwelling. Effects of the Invention Thus, according to the present invention, it is possible to obtain a catheter that is easy to insert into a blood vessel of a living body, is soft and suitable for indwelling in a blood vessel for high-calorie infusion without damaging the blood vessel after being inserted into the living body. It is extremely useful in clinical medicine.

[Brief explanation of drawings]

FIG. 1 is a drawing showing the temperature dependence of the in-liquid hardness of the hydrophilic vascular indwelling catheter of the present invention and a comparative example catheter, and FIG. 2 is a drawing showing the time dependence of the in-liquid hardness of the hydrophilic vascular indwelling catheter of the present invention.

Claims (1)

[Scope of Claims] 1. An indwelling catheter that is molded using a hydrophilic polyurethane-based polymer material, the insertion portion of which softens when the catheter is inserted into a living body. 2. The indwelling catheter according to claim 1, wherein the hydrophilic polyurethane polymer material is a prepolymer composed of a hydrophilic polyol and a diisocyanate with low hydrophobicity. 3. The indwelling catheter according to claim 1, wherein the hydrophilic polyurethane-based polymer material is made of a polymer blend of polyurethane and a hydrophilic polymer that is compatible with the polyurethane. 4. The indwelling catheter according to claim 1, wherein the polymeric material is made of a copolymer of polyurethane and a hydrophilic polymer.