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Methods and systems for processing complex shaped hydrogel devicesRelated Patent Categories: Plastic And Nonmetallic Article Shaping Or Treating: Processes, Optical Article Shaping Or Treating, Nonmechanical Aftertreatment (e.g., Hydration Of Contact Lens, Extraction, Heat Treatment, Etc.)Methods and systems for processing complex shaped hydrogel devices description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070182039, Methods and systems for processing complex shaped hydrogel devices. Brief Patent Description - Full Patent Description - Patent Application Claims
RELATED PATENT APPLICATIONS [0001] This application claims priority to Provisional Patent Application U.S. Ser. No. 60/751,783 which was filed on Dec. 20, 2005. FIELD OF THE INVENTION [0002] This invention relates to processing complex shaped hydrogel devices, specifically including methods of processing ophthalmic lenses made from silicone hydrogels in order to leach components from the lenses and release the lenses from molds. BACKGROUND OF THE INVENTION [0003] It is well known that contact lenses can be used to improve vision. Various contact lenses have been commercially produced for many years. Early designs of contact lenses were fashioned from hard materials. Although these lenses are still currently used in some applications, they are not suitable for all patients due to their poor comfort and relatively low permeability to oxygen. Later developments in the field gave rise to soft contact lenses, based upon hydrogels. [0004] Hydrogel contact lenses are very popular today. These lenses are often more comfortable to wear than contact lenses made of hard materials. Malleable soft contact lenses can be manufactured by forming a lens in a multi-part mold where the combined parts form a topography consistent with the desired final lens. [0005] Multi-part molds used to fashion hydrogels into a useful article of a complex shape, such as an ophthalmic lens, can include for example, a first mold portion with a convex surface that corresponds with a back curve of an ophthalmic lens and a second mold portion with a concave surface that corresponds with a front curve of the ophthalmic lens. To prepare a lens using such mold portions, an uncured hydrogel lens formulation is placed between the concave and convex surfaces of the mold portions and subsequently cured. The hydrogel lens formulation may be cured, for example by exposure to either, or both, heat and light. The cured hydrogel forms a lens according to the dimensions of the mold portions. [0006] Following cure, traditional practice dictates that the mold portions are separated and the lens remains adhered to one of the mold portions. A release process detaches the lens from the remaining mold part. The extraction step removes unreacted components and diluents (hereinafter referred to as "UCDs") from the lens and affect clinical viability of the lens. If the UCDs are not extracted from the lens, they may make the lens uncomfortable to wear. [0007] According to prior art, release of the lens from the mold can be facilitated by exposure of the lens to aqueous or saline solutions which act to swell the lens and loosen adhesion of the lens to the mold. Exposure to the aqueous or saline solution can additionally serve to extract UCDs and thereby make the lens more comfortable to wear and clinically acceptable. [0008] New developments in the field have led to contact lenses that are made from silicone hydrogels. Known hydration processes using aqueous solutions to effect release and extraction have not been efficient with silicone hydrogel lenses. Consequently, attempts have been made to release silicone lenses and remove UCDs using organic solvents. Processes have been described in which a lens is immersed in an alcohol (ROH), ketone (RCOR'), aldehyde (RCHO), ester (RCOOR'), amide (RCONR'R'') or N-alkyl pyrrolidone for 20 hours-40 hours and in the absence of water, or in an admixture with water as a minor component (see e.g., U.S. Pat. No. 5,258,490). [0009] However, although some success has been realized with the known processes, the use of highly concentrated organic solutions can present drawbacks, including, for example: safety hazards; increased risk of down time to a manufacturing line; high cost of release solution; and the possibility of collateral damage, due to explosion. [0010] Therefore, it would be advantageous to find a method of producing a silicone hydrogel contact lens which requires the use of little or no organic solvent, avoids the use of flammable agents, that effectively releases lenses from the molds in which they were formed, and which removes UCDs from the lens. SUMMARY OF THE INVENTION [0011] Accordingly, the present invention provides methods of releasing a silicone hydrogel contact lens from a mold and leaching the lens of UCDs without soaking the lens in organic solvents. According to the present invention, release of a silicone hydrogel lens from a mold in which the lens is formed is facilitated by exposing the lens to an aqueous solution of an effective amount of a release aid. In addition, leaching of UCDs from the lens is also facilitated by exposing the lens to an aqueous solution of an effective amount of a leach aid [0012] The present invention further relates to a contact lens produced using a method which comprises treating the cured lens in an aqueous solution of an effective amount of a release aid and to ophthalmic lenses produced using a method comprising treating the cured lens in an aqueous solution of an effective amount of a leaching aid. DETAILED DESCRIPTION OF THE INVENTION [0013] It has been found that a silicone hydrogel ophthalmic lens can be released from a mold in which it was cured by exposing the cured lens to an aqueous solution of an effective amount of a release aid. It has also been found that adequate removal of Leachable Materials from the silicone hydrogel ophthalmic lens can be realized by exposing the cured lens to an aqueous solution of an effective amount of a leach aid. [0014] Definitions [0015] As used herein, "adequate removal of Leachable Materials" means that at least 50%, of the Leachable Materials have been removed from a lens after treating the lens. [0016] As used herein, "Leachable Material" includes UCD's and other material which is not bound to the polymer and may be extracted from the polymer matrix, for example, by leaching with water or an organic solvent. [0017] As used herein, a "Leaching Aid" is any compound that if used in an effective amount in an aqueous solution to treat a ophthalmic lens can yield a lens with an adequate amount of removal of Leachable Materials. [0018] As used herein the term "monomer" is a compound containing at least one polymerizable group and an average molecular weight of about less than 2000 Daltons, as measured via gel permeation chromatography refractive index detection. Thus, monomers can include dimers and in some cases oligomers, including oligomers made from more than one monomeric unit. [0019] As used herein, the term "Ophthalmic Lens" refers to devices that reside in or on the eye. These devices can provide optical correction, wound care, drug delivery, diagnostic functionality, cosmetic enhancement or effect or a combination of these properties. The term lens includes but is not limited to soft contact lenses, hard contact lenses, intraocular lenses, overlay lenses, ocular inserts, and optical inserts. Continue reading about Methods and systems for processing complex shaped hydrogel devices... Full patent description for Methods and systems for processing complex shaped hydrogel devices Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Methods and systems for processing complex shaped hydrogel devices patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. 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