Method for sterilizing a medical device having a hydrophilic coating
A method for sterilizing a medical device having a hydrophilic coating using radiation, said method including the steps of bringing the medical device having such coating in contact with an aqueous liquid for wetting the hydrophilic coating, said liquid including a solution of a hydrophilic polymer, and sterilizing the device by applying a sufficient amount of radiation to provide a coated device showing a significantly increased and prolonged water retention and lower friction coefficient when wet.
1. A method for sterilizing a medical device having a hydrophilic coating, said method comprising the steps: bringing the medical device having such coating in contact with an aqueous liquid for wetting the hydrophilic coating, said liquid containing a solution of a hydrophilic polymer, and sterilizing the device by applying a sufficient amount of radiation while the device is in contact with the aqueous liquid.
2. A method as claimed in claim 1 , wherein the hydrophilic polymer is a synthetic polymer.
3. A method as claimed in claim 2 , wherein the hydrophilic polymer is selected from the group consisting of polyvinylpyrrolidone or copolymer containing N-vinylpyrrolidone, poly(meth)acrylic acid or copolymer containing (meth)acrylic acid or a (meth)acrylic acid ester, a polyacrylamide, polyvinylalcohol and a copolymer of a partially saponified vinylacetate copolymer, polyethyleneglycol, polyvinylmethylether, polyvinylmethylether-maleic anhydride and a copolymer containing maleic-anhydride or a maleic-acidester or a copolymer containing vinylmethyl-ether.
4. A method as claimed in claim 3 , wherein the hydrophilic polymer is polyvinylpyrrolidone or a copolymer thereof.
5. A method as claimed in claim 1 , wherein the hydrophilic polymer is a polysaccharide.
6. A method as claimed in claim 5 , wherein the hydrophilic polymer is a member selected from the group consisting of a water soluble polysaccharide, Xanthane and a derivative of either.
7. A method as claimed in claim 6 , wherein the hydrophilic polymer is CMC or a derivative thereof.
8. A sterilized set comprising a medical device provided with a hydrophilic coating and an aqueous liquid for wetting the hydrophilic coating wherein said device is in contact with the aqueous liquid, wherein said set has been sterilized using radiation while in contact with said liquid comprising a solution of a hydrophilic polymer.
9. A set as claimed in claim 8 wherein the aqueous liquid is in a package also comprising the medical device provided with a hydrophilic coating.
10. A method of protecting a hydrophilic coating of a medical device having such coating during sterilizing using radiation which comprises bringing, wherein the coating into contact with an aqueous solution containing a hydrophilic polymer, and exposing the coating to the radiation while in contact with the aqueous solution.
11. A method of preparing a sterilized catheter having a crosslinked two-layer hydrophilic coating comprising the steps of
a) preparing a solution of polyvinyl pyrrolidone dissolved in an ethanol/gamma butyrolactone solvent mixture,
b) dipping a raw catheter in the solution and letting it dry at ambient temperature,
c) dipping the resulting catheter in a PVP-solution containing urea and an ethanol/gamma butyrolactone (85/15) solvent mixture,
d) further drying at elevated temperature,
e) cross-linking the polyvinylpyrrolidone by exposing the coated catheter to UV-light having a wave length range between 200 and 300 nm for from ½ to 15 minutes, and
f) sterilizing the coated catheter while wetted with a solution of PVP by irradiation.
12. A method of preparing a sterilized catheter having a crosslinked hydrophilic coating with an unsaturated poly(methyl vinyl ether/maleic anhydride)/hydroxyethylmethacrylate(HEMA) prepolymer comprising the steps of
a) preparing a solution of poly(methyl vinyl ether/maleic anhydride) in acetone in a reaction vessel equipped with a stirrer, keeping the reaction mixture at room temperature while adding 1-methylimidazole as a catalyst and hydroxyethylmethacrylate dropwise to the stirred polymer solution during a period of 30 minutes,
b) stirring the mixture for a sufficient time up to 10 hours at room temperature,
c) preparing a primer mixture by dissolving a medical grade polyurethane and the poly(methyl vinyl ether/maleic anhydride)/HEMA unsaturated prepolymer in a mixture of THF and acetone,
d) coating a raw catheter with a primer by dipping it in the resulting solution,
e) dipping the resulting catheter in the solution of poly(methyl vinyl ether/maleic anhydride)/HEMA unsaturated prepolymer in acetone for applying a top coat,
f) drying the resulting catheter,
g) cross-linking the poly(methyl vinyl ether/maleic anhydride)/HEMA unsaturated prepolymer polyvinylpyrrolidone by exposing the coated catheter to 5 M rads from a high energy electron beam source, and
h) sterilizing the coated catheter while wetted with a solution of PVP by irradiation.
13. A method as claimed in claim 6 , wherein the water soluble polysaccharide is a member selected from the group consisting of carboxymethylcellulose (CMC) and hydroxyethylcellulose.
14. A sterilized set as claimed in claim 8 wherein the hydrophilic polymer is polyvinylpyrrolidone or a copolymer thereof.