Surgery – Diagnostic testing – Flexible catheter guide
Reexamination Certificate
2000-11-17
2003-04-01
Hindenburg, Max F. (Department: 3736)
Surgery
Diagnostic testing
Flexible catheter guide
C600S435000, C604S264000, C623S001110
Reexamination Certificate
active
06540698
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a medical device and its production method. More specifically, this invention relates to a medical device having a surface exhibiting excellent wet lubricity owing to the high molecular weight compound on the surface of the device, as well as its production method.
2. Prior Art
Materials used in producing catheters, guide wires and other medical devices should be capable of exhibiting surface lubricity since reduction in frictional resistance of the surface is critical for reducing tissue damage and improving the operational capability.
Typical methods that have been employed for reducing the surface frictional resistance include use of a material exhibiting reduced friction such as Teflon™ which is inherently provided with low friction, and coating of various oils on the surface of the substrate. These methods, however, suffered from insufficient reduction in the frictional resistance or insufficient retention of the lubricity.
Another method that has been employed for the surface lubrication is the lubrication by coating a hydrophilic polymer on the surface. Such coating is superior to the use of Teflon™ or oil coating as described above in the lubricity. However, it has been generally conceived that such coating is inferior in durability, and various methods have been proposed for improving the durability.
JP-B 59-19582, for example, discloses a surface-lubricating method wherein polyvinyl pyrrolidone (PVP) which is a hydrophilic polymer and isocyanate group which is a reactive functional group are used to form a network of chemical bond for immobilization of the PVP to the substrate surface. JP-B 59-193766 discloses a surface lubrication method by the reaction between polyethylene oxide (PEO) and isocyanate group. JP-B 1-55023 discloses a surface lubrication method wherein the surface is coated with a combination of a copolymer comprising two or more types of monomers having a functional group and isocyanate group.
These methods, however, utilized the reaction between a highly reactive proton-accepting functional group as represented by isocyanate and a proton-donating functional group, and a consequence, suffered from the problems of limitation of the solvent used to non-proton-donating organic solvents, complicated coating procedure, and necessity for a strict moisture control of the coating solution and the working area.
As an example of more recent technology, JP-A 10-5325 discloses a surface lubrication method using polyurethane emulsion wherein phenomenon of the reactivation of the once blocked isocyanate group (or carboxyl group) by temperature elevation is utilized. This reaction, however, requires a high reaction temperature, and use of this reaction in the surface lubrication is associated with a fair risk that the substrate may loose its physical properties that are primarily required for the substrate since the temperature of the substrate is also elevated.
In the method wherein the surface lubricity is realized by using a hydrophilic polymer, the hydrophilic polymer is generally immobilized on the surface of the substrate by the coating operation, and affinity of the coated surface with water is then improved by the step wherein the coated surface is brought in contact with water, for example, by immersing in water or contacting with steam. Such procedure has the merit that the surface lubricity is more quickly realized upon wetting. However, in the surface lubrication method, the solvent used for the coating is generally an organic solvent, and the step of contacting with water should be effected subsequent to and separately from the coating step. This results in the complicated production process and increased cost.
When a physiological activity such as anti-thrombogenicity is to be imparted with the surface in addition to the lubricity by using a water-soluble physiologically active substance such as heparin, the step of imparting the lubricity by coating the surface with a solution of a hydrophilic polymer in an organic solvent had be carried out separately from the step of imparting the physiological activity by treating the surface with a solution of the water-soluble physiologically active substance in an aqueous solvent since the water-soluble physiologically active substance is generally insoluble in an organic solvent. In other words, the step of imparting the lubricity and the step of imparting the physiological activity could not be completed in the same step, and there had been the problem of complicated procedure.
SUMMARY OF THE INVENTION
In view of the situation as described above, an object of the present invention is to obviate the problems as described above, and to provide a highly safe medical device which has been imparted with long lasting lubricity under moderate coating conditions without using the highly reactive proton-accepting functional group as represented by isocyanate group, and with no loss in the physical properties primarily required for the substrate of the medical device; and a method for producing such medical device.
Another object of the present invention is to provide a medical device which has been imparted with the surface lubricity in simplified procedure by conducing the step of contacting the surface with water and the step of coating the surface in the same step, and as a consequence, a medical device which has been imparted with the surface lubricity at a reduced cost; and a method for producing such medical device.
Further object of the present invention is to provide a medical device exhibiting stable lubricity and physiological activity wherein a water-soluble physiologically active substance such as heparin has been reliably immobilized on its surface in a reliable, simple coating operation simultaneously with the substance responsible for the lubricity; and a method for producing such medical device.
The objects as described above are attained by the present invention as summarized (1) to (15), below.
(1) A medical device having a surface exhibiting lubricity when wet wherein the medical device has a surface lubrication layer formed on a substrate constituting the medical device, and said surface lubrication layer comprises a reaction product of a hydrophilic high molecular weight compound having at least one carbonyl group in the molecule and a cross-linking agent comprising a hydrazide compound having at least two hydrazine residues in one molecule.
(2) A medical device having a surface exhibiting lubricity when wet wherein the medical device has a surface lubrication layer formed on a substrate constituting the medical device, and said surface lubrication layer comprises a reaction product of a hydrophilic high molecular weight compound having at least one hydrazine residue in the molecule and a cross-linking agent comprising a carbonyl group-containing compound having at least two carbonyl groups in one molecule.
(3) The medical device according to (1) or (2) wherein said surface lubrication layer further comprises a water-soluble or water-swellable high weight molecular substance.
(4) The medical device according to any one of (1) to (3) wherein said cross-linking agent is soluble in an aqueous solvent.
(5) A medical device having a surface exhibiting lubricity when wet wherein the medical device has a surface lubrication layer formed on a substrate constituting the medical device, and said surface lubrication layer has an interpenetrating network comprising a reaction product of a carbonyl group-containing compound having at least one carbonyl group in the molecule with a hydrazide compound having at least two hydrazine residues in one molecule and a water-soluble or water-swellable high molecular weight substance.
(6) A medical device having a surface exhibiting lubricity when wet wherein the medical device has a surface lubrication layer formed on a substrate constituting the medical device, and said surface lubrication layer has an interpenetrating network comprising a reaction product of a hydrazide compound having at
Burns Doane , Swecker, Mathis LLP
Hindenburg Max F.
Marmor II Charles
Terumo Kabushiki Kaisha
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