Release aids for releasing silicone hydrogel ophthalmic lenses

Abstract

This invention includes methods and systems for processing hydrogel biomedical devices, such as ophthalmic lenses using polyethylene glycol to facilitate release of the devices from a mold part.

1 . A method of processing an ophthalmic lens comprising silicone hydrogel, the method comprising:
 depositing a lens forming resin on a lens forming surface of a first mold part;   bringing the lens forming mixture into contact with a second lens forming surface of a second mold part, wherein the first mold part and the second mold part are configured to receive each other such that a cavity is formed between the first lens forming surface and the second lens forming surface and wherein the cavity defines the shape of the ophthalmic lens;   exposing the lens forming resin to polymerization initiating conditions to form a lens from the lens forming resin and adheres the lens to at least one of: the firs mold part and the second mold part;   separating the first mold part from the second mold part such that the formed ophthalmic lens remains adhered to at least one of the first mold part and the second mold part; and   exposing the ophthalmic lens to a first hydration solution comprising an amount of polyethylene glycol sufficient to facilitate release of the lens from a mold part in which the device is formed.   
     
     
         2 . The method of  claim 1  wherein the amount of polyethylene glycol sufficient to facilitate release of the lens from a mold part in which the device is formed comprises between about 800 parts per million and 1200 parts per million of polyethylene glycol. 
     
     
         3 . The method of  claim 1  wherein the amount of polyethylene glycol sufficient to facilitate release of the lens from a mold part in which the device is formed comprises between about 500 parts per million and 2000 parts per million of polyethylene glycol. 
     
     
         4 . The method of  claim 1  wherein the method additionally comprises the step of exposing the lens and the mold part to a second hydration solution comprising deionized water to rinse the first hydration solution from the lens. 
     
     
         5 . The method of  claim 1  wherein the polymerization initiating conditions comprises actinic radiation. 
     
     
         6 . The method of  claim 1  wherein the polymerization initiating conditions comprises actinic radiation and heat. 
     
     
         7 . The method of  claim 1  wherein the amount of said polyethylene glycol sufficient to facilitate release of the device from the mold part in which the device is formed comprises between 0.05 to 5 weight %. 
     
     
         8 . The method of  claim 1  wherein the amount of said polyethylene glycol sufficient to facilitate release of the device from a mold part in which the device is formed comprises between 0.01 to 3 weight %. 
     
     
         9 . The method of  claim 1 , wherein the biomedical device is a silicone hydrogel contact lens. 
     
     
         10 . The method of  claim 3 , wherein the wherein the polyethylene glycol comprises PEG 2000. 
     
     
         11 . The method of  claim 3 , wherein the wherein the polyethylene glycol comprises mPEG. 
     
     
         12 . The method of  claim 3 , wherein the polyethylene glycol comprises PEG DME.