Process for producing slippery, tenaciously adhering hydrogel coatings containing a polyurethane-urea polymer hydrogel commingled with at least one other, dissimilar polymer hydrogel

A process for producing a sterilized coating of a reactivatable, dried, tenaciously adhering, commingled hydrogel of a hydrophilic polyurethane-polyurea polymer hydrogel and at least one other polymer hydrogel different from said polyurethane-polyurea polymer hydrogel, on the surface of a medical device fabricated from a polymeric substrate or a metallic substrate, said process comprising:

• (a) making at least a portion of an outer surface of said polymeric or metallic substrate from which said medical device is fabricated chemically reactive by affixing reactive chemical functional groups, including at least some amine-containing groups, thereto;
• (b) coating the resulting reactive outer surface of said substrate with a first coating comprising a hydrophilic polyurethane-urea prepolymer intermediate, which is capable of forming a polyurethane-polyurea hydrogel-forming polymer, and which contains terminal isocyanate groups, such that at least some of said terminal isocyanate groups are reacted with and are covalently bonded to said reactive chemical functional groups on said outer surface of said polymeric or metallic substrate, forming covalent polyurea bonds therewith, resulting in the formation of a tie coat of a polyurethane-polyurea hydrogel-forming polymer, that tenaciously adheres to said reactive outer surface of said substrate, and wherein at least some of said terminal isocyanate groups of said polyurethane-urea prepolymer intermediate are present in said polyurethane-polyurea hydrogel-forming polymer, such that they remain free to react with other species;
• c) coating said tie coat with a second coating comprising at least one other hydrogel-forming polymer, different from said polyurethane-polyurea hydrogel-forming polymer, and a moisture-containing, hydrogel-forming substance, which also contains isocyanate-reactive chemical functional groups, such that a barrier coat of a wet, slippery, commingled hydrogel is formed upon the application of said second coating to said tie coat of said first coated substrate;
• wherein said isocyanate-reactive functional groups of said hydrogel-forming substance are reacted with and are covalently bonded to at least some of said terminal isocyanate groups of said polyurethane-polyurea hydrogel-forming polymer that remain free to react with other species, to form a first hydrogel of said commingled hydrogel barrier coat, such that said first hydrogel of said commingled hydrogel barrier coat is a polyurethane-polyurea polymer hydrogel that is tenaciously adhering to said tie coat, and thus also tenaciously adhering to said substrate surface;
• wherein said moisture of said hydrogel-forming substance is bound with said other hydrogel-forming polymer different from said polyurethane-polyurea hydrogel-forming polymer, to form a second hydrogel of said commingled hydrogel barrier coat, such that said second hydrogel of said commingled hydrogel barrier coat is a hydrogel of said other hydrogel-forming polymer;
• and
• wherein said first hydrogel of said commingled hydrogel barrier coat and said second hydrogel of said commingled hydrogel barrier coat are commingled with one another, such that said second hydrogel of said commingled hydrogel barrier coat is thereby rendered tenaciously adhering to said tie coat and thus also tenaciously adhering to said substrate surface;
• (d) drying said wet, slippery commingled hydrogel barrier coat formed in (c) to form a dried hydrogel coating thereof;
• and
• (e) sterilizing the resulting coated medical device, bearing said dried hydrogel coating of (d).