Method for applying a coating onto a silicone hydrogel lens
View Patent ↗The invention provides a cost-effective and in-situ method for applying an LbL coating onto a silicone hydrogel contact lens directly in a lens package. The resultant silicone hydrogel contact lens has a coating with good hydrophilicity, intactness and durability and also can be used directly from the lens package by a patient without washing and/or rising. In addition, the invention provides a packaging solution for in-situ coating of a silicone hydrogel contact lens in a lens package and an ophthalmic lens product.
1. A method for applying a hydrophilic coating onto a silicone hydrogel contact lens, comprising the steps of:
(a) placing the contact lens in a lens package containing a packaging solution, thereby forming an LbL coating on the contact lens, wherein the packaging solution comprises a polyionic material and at least one hydrolysable-at-autoclave material, wherein the polyionic material includes (i) a polymer having a hydrophobic backbone and multiple charged or ionizable pendant groups, (ii) a chitosan, or (iii) a combination thereof, wherein the packaging solution has an initial pH of less than about 4.0, wherein the hydrolysable-at-autoclave material is present in the packaging solution in an amount sufficient to impart a final neutral pH to the packaging solution after the package with the contact lens therein is autoclaved;
(b) sealing the lens package with the contact lens and the packaging solution having the initial pH of less than about 4.0 therein; and
(c) autoclaving said sealed package with the contact lens and the packaging solution therein, thereby hydrolyzing the hydrolysable-at-autoclave material and imparting the final neutral pH to the packaging solution in the sealed package,
wherein the LbL coating has a hydrophilicity characterized by an averaged water contact angle of about 80 degrees or less.
2. The method of claim 1 , wherein the polyionic material includes a polyanionic material having a hydrophobic backbone and pendant ionizable groups, and wherein the hydrolysable-at-autoclave material is urea, ammonium carbamate, or combination thereof.
3. The method of claim 2 , wherein the polyanionic material comprises carboxyl groups.
4. The method of claim 2 , wherein the polyanionic material is a linear or branched polyacrylic acid, or a linear or branched acrylic acid copolymer.
5. The method of claim 4 , wherein the packaging solution further comprises a polycationic material.
6. The method of claim 5 , wherein the concentration of the polyanionic material is at least 2 folder higher than that of the polycationic material.
7. The method of claim 4 , wherein the packaging solution further comprises a non-charged hydrophilic material with a hydrophobic backbone, wherein the non-charged hydrophilic material is a polyvinyl alcohol, a homopolymer of a vinyl lactam, a copolymer of at least one vinyl lactam in the presence or in the absence of one or more hydrophilic vinylic comonomers, or a mixture thereof.
8. The method of claim 7 , wherein the non-charged hydrophilic material is a polyvinyl alcohol, a homopolymer of a vinyl lactam, a copolymer of at least one vinyl lactam in the presence or in the absence of one or more hydrophilic vinylic comonomers, or a mixture thereof.
9. The method of claim 4 , wherein the packaging solution further comprises a chitosan.
10. The method of claim 1 , wherein the polyionic material includes a chitosan, and wherein the hydrolysable-at-autoclave material is urea, ammonium carbamate, or combination thereof.