JPS6255427B2 - - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to medical devices, and more particularly, to medical devices formed from migratory-free polymeric materials. Prior Art and Problems Medical devices, especially tubes for transporting medical liquids such as catheters, are currently made of flexible polyvinyl chloride (PVC) due to their flexibility, transparency, and economy. many. However, soft PVC contains large amounts of migratory substances such as plasticizers (eg, dioctyl phthalate (DOP), etc.). For example, when a tube made of soft PVC is brought into contact with a medical liquid such as drug solution or blood for a long period of time, this plasticizer will be eluted and transferred into the liquid.
As a result, the physical properties of the tube, particularly its flexibility, may deteriorate. In addition, the effects of plasticizers transferred into liquids on the human body have been discussed. Therefore, in order to solve the problem of DOP elution, plasma treatment of soft PVC containing DOP and plasticizers with low migration properties are being considered to replace DOP, but these are not fully satisfactory. There are also questions about its safety. Also,
There is also soft PVC that uses a polymer plasticizer instead of a low-molecular plasticizer like DOP, but this has lower plasticizing efficiency than low-molecular plasticizers, and like DOP, its safety is questionable. . On the other hand, alternative materials to soft PVC, such as polyethylene and polyurethane, are being considered, but polyethylene is less versatile than conventional soft PVC in terms of physical properties, especially flexibility and transparency, for use in medical devices. Also, polyurethane is not very versatile in terms of economy. Purpose of the Invention Therefore, the purpose of the present invention is to provide a medical device that does not use a plasticizer containing a migratory substance and has excellent flexibility and transparency. According to this invention, at least the portion that is in contact with body fluids or blood and that requires flexibility is a styrene-butadiene radial block copolymer [A] with a butadiene unit content of 5 to 40% by weight. % by weight, and from 95 to 50% by weight of a styrenic thermoplastic elastomer. The styrenic thermoplastic elastomer is usually a styrene-butadiene-styrene teleblock copolymer with a butadiene unit content of 40 to 90% by weight, a styrene-butadiene single block copolymer with a butadiene unit content of 40 to 90% by weight,
A styrene-butadiene radial block copolymer [B] with a butadiene unit content of 40 to 90% by weight, a styrene-olefin-styrene terrestrial block copolymer with an olefin unit content of 40 to 90% by weight, or two or more of these. It is a mixture of Preferably, the medical device of the invention is in the form of a medical liquid delivery tube. DETAILED DESCRIPTION OF THE INVENTION As a result of various studies on materials for medical devices that could replace flexible PVC, the present inventors discovered that a certain type of styrene-butadiene radial block copolymer and a styrene thermoplastic elastomer were used in a predetermined ratio. By blending, it has transparency, excellent flexibility and appropriate elasticity, good moldability, and transferability to artificial gastric fluid [I] (pharmacopoeia), artificial intestinal fluid (pharmacopoeia), etc. The inventors have discovered that it is possible to obtain a polymer material suitable for medical devices that does not substantially contain substances, and have completed the present invention. The medical devices of the present invention include medical liquid transport tubes such as catheters, infusion tubes, blood transfusion tubes, extracorporeal circulation blood circuit tubes, etc., and blood separation bags. Particularly preferred are the medical liquid delivery tubes mentioned above, especially catheters. Hereinafter, the present invention will be described in detail using a suction catheter as an example of a medical device with reference to the drawings. The suction catheter shown in the accompanying drawings has an internal diameter of e.g.
It comprises a tube 11 having a diameter of 1.7 to 4.5 mm and an outer diameter of 2.7 to 6.7 mm and made of a polymeric material as will be described in detail hereinafter. A hard plastic adapter 12 is provided at one end of the tube 11. Further, the other open end of the tube 11 forms a certain angle with respect to the tube wall, and a suction port 13 is formed in the tube wall in the vicinity thereof. Tube 11 is a styrene-butadiene radial block copolymer [A] having a butadiene unit content of 5 to 40% by weight, preferably 10 to 25% by weight.
5 to 50% by weight, preferably 10 to 40% by weight and 95 to 50% by weight of styrenic thermoplastic elastomer
% by weight, preferably from 90 to 60% by weight of a polymeric material. In this polymer material, the styrene-butadiene radial block copolymer plays a role in imparting appropriate hardness and good moldability to the flexible and elastic styrene thermoplastic elastomer, and its butadiene unit content is 5. If it is less than % by weight, hardness increases too much and transparency is impaired. On the other hand, if the butadiene unit content exceeds 40% by weight, it will become too soft and cannot be given appropriate hardness, so it will easily bend during use, causing blockage of the tube or loss of surface smoothness. or The molecular weight is usually around 5
It is between 10,000 and 200,000. The other component of the above polymer material, the styrene thermoplastic elastomer, is an elastomer having styrene blocks as hard segments and butadiene or olefin blocks as soft segments. Examples include styrene-butadiene-styrene teleblock copolymers with a butadiene unit content of 40 to 90% by weight, styrene-butadiene single block copolymers with a butadiene unit content of 40 to 90% by weight, and olefin unit content. It is a 40 to 90% by weight styrene-olefin-styrene block copolymer or a mixture of two or more of these. These styrenic thermoplastic elastomers are commercially available. Polymer materials made of the above components and blending ratios have good compatibility among the components, so they are transparent, do not contain low-molecular plasticizers or stabilizers, have excellent flexibility, and have good moldability. . Furthermore, the flexibility of this polymer material is less sensitive to temperature changes, and it does not stiffen at low temperatures like soft PVC. In order to produce the medical device of the present invention using the polymer material described above, conventional extrusion molding, injection molding, etc., particularly extrusion molding, can be used. Examples of this invention will be described below. Example 1 Catheter tubes as shown in the attached drawings were produced by extrusion molding from polymer materials having the six compounding ratios shown in Table 1. Table 2 shows the results of examining various physical properties and safety of these catheter tubes.

【table】

[Table] After dry blending in the proportions shown in Table 1,
Direct extrusion molding machine (φ20mm screw, L/D=
20, compression ratio = 2.25), inner diameter 3.1mm, outer diameter
A 4.7 mm tubular tube molded product was extruded. The migration properties of the materials contained in the catheter tube thus prepared were evaluated by immersing the catheter tube of the present invention in artificial gastric fluid (Japanese Pharmacopoeia, JPX) and artificial intestinal fluid (Japanese Pharmacopoeia, JP) at 37°C ± 0.25 for 28 days. The weight change rate (%) afterward was expressed as [{(weight after 28 days) - (weight before immersion)}/weight before immersion]×100.
A negative sign was given if the weight decreased after 28 days of immersion, and a positive sign was given if it increased. As a comparative example, a catheter tube made of soft PVC containing 34% by weight of DOP as a plasticizer was also taken up.

【table】

[Table] As shown in Table 2, the weight loss rate of the product of the present invention is significantly lower than that of soft PVC, and the styrene-butadiene radial block copolymer [A]
It was confirmed that the weight loss rate was lower than that of D, which had more than 50% by weight, and E and F, which had less than 5% by weight. In addition, the product of the present invention passed the safety test according to the Ministry of Health and Welfare standards (standard for vinyl chloride resin blood sets), and the moldability results evaluated by tube surface smoothness and the visual transparency results.
All the results of flexibility evaluated by tensile stress at 100% elongation were also good. Example 2 A tube for a catheter as shown in the attached drawings was prepared by the same method as shown in Example 1 from polymer materials having the two types of compounding ratios shown in Table 3. Table 4 shows the results of examining various physical properties and safety of these catheter tubes.

【table】

【table】

[Table] Specific Effects of the Invention The medical device of the present invention has excellent flexibility because at least the portion that comes into contact with body fluids or medical fluids and requires flexibility is formed of the above-mentioned polymer material. It has minimal loss of flexibility even at low temperatures, and since it does not contain migratory substances, there is no change in physical properties due to elution or migration of the contained substances even if it comes into contact with blood or drug solutions for a long time, so it is safe. is also excellent. In addition, especially in the case of medical instruments such as catheters in which the distal end of the tube is operated by operating the rear end of the tube, the operability is very excellent.

[Brief explanation of the drawing]

The accompanying drawing is a front view of a suction catheter according to one embodiment of the present invention. 11...tube, 12...adapter, 13
...Suction port.

Claims (1)

[Scope of Claims] 1. At least the portion that comes into contact with body fluids or medical fluids and that requires flexibility and transparency is a styrene-butadiene radial block copolymer 5 or 5 with a butadiene unit content of 5 to 40% by weight. A medical device in the form of a medical liquid conveying tube, characterized in that it is made of a polymeric material consisting of 50% by weight and 95 to 50% by weight of a styrenic thermoplastic elastomer. 2 The styrenic thermoplastic elastomer is a styrene-butadiene-styrene teleblock copolymer with a butadiene unit content of 40 to 90% by weight, a styrene with a butadiene unit content of 40 to 90% by weight.
Butadiene single block copolymer, styrene-butadiene radial block copolymer with a butadiene unit content of 40 to 90% by weight, styrene-olefin-styrene teleblock copolymer with an olefin unit content of 40 to 90% by weight, or any of these. The medical device according to claim 1, which is a mixture of two or more of the above.