Patent ID: 8557334

Claim:
A method of producing a silicone hydrogel contact lens having a hydrophilic coating which is covalently attached to the polymer matrix of the silicone hydrogel contact lens, comprising the steps of: (a) polymerizing, in a mold, a polymerizable composition comprising at least one silicone-containing vinylic monomer or macromer and an azlactone-containing vinylic monomer or macromer, thereby forming a silicone hydrogel contact lens having azlactone moieties covalently attached onto the polymer matrix of the contact lens, wherein the azlactone-containing vinylic monomer or macromer is present in an amount of about 0.5% to about 5.0% by weight in the polymerizable composition; (b) contacting the contact lens with a solution of an anchoring hydrophilic polymer having pendant primary or secondary amino groups for a period of time sufficient to form a prime coating on the contact lens, wherein the prime coating comprises a layer of the anchoring hydrophilic polymer covalently attached to the surface of the contact lens through one or more covalent linkages each formed between one azlactone moiety at or near the surface of the contact lens and one of the pendant primary or secondary amino groups of the anchoring hydrophilic polymer; (c) applying a top coating on top of the prime coating to form the hydrophilic coating with an increased surface hydrophilicity and/or durability with respect to the prime coating, wherein the top coating comprises at least one layer of a carboxylic acid-containing hydrophilic polymer and/or at least one layer of an azetidinium-containing polymer, wherein the layer of the carboxylic acid-containing hydrophilic polymer is formed by contacting the contact lens having the prime coating thereon with a solution of the carboxylic acid-containing hydrophilic polymer, wherein the layer of the azetidinium-containing polymer is formed by contacting the contact lens having the prime coating thereon and optionally the layer of the carboxylic acid-containing hydrophilic polymer with a solution of the azetidinium-containing polymer, wherein the layer of the carboxylic acid-containing hydrophilic polymer and/or the layer of the azetidinium-containing polymer is chemically and/or physically bound to the layer of the anchoring hydrophilic polymer, wherein the anchoring hydrophilic polymer is a polyhydroxyl polymer which is a derivative of a poly(vinyl alcohol) and has from about 0.5% to about 80%, based on the number of hydroxyl groups in the poly(vinyl alcohol), of units of the formula I in which R 5 is hydrogen, a C 1 -C 6 alkyl group or a cycloalkyl group; R 6 is linear or branched alkylene having up to up to 8 carbon atoms; and R 7 is a primary or secondary amino group of the formula N + H 2 (R′)X − , in which R′ is hydrogen or a C 1 -C 4 alkyl radical; and X is a counterion selected from the group consisting of HSO 4 − , F − , Cl − , Br − , I − CH 3 COO − , OH − , BF − , or H 2 PO 4 − .