Incorporation of absorbents during extraction and/or hydration of hydrogel materials used as ophthalmic devices
First Claim
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1. A method for extracting unreacted monomers and partially reacted oligomers from a hydratable xerogel polymer containing said monomers and oligomers wherein said polymer after hydration is in the form of an ophthalmic device which method comprises:
- (a) incorporating an adsorbent into an aqueous solution wherein said absorbent is selected from the group consisting of activated carbon, silica gel and an organic solvent forming a two-phase system with water; and
(b) contacting said hydratable xerogel polymer, prior to hydration, with the solution produced in (a) above and maintaining said polymer in such contact under conditions sufficient to reduce the concentration of said monomers and oligomers in said polymer.
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Abstract
Disclosed are methods for extracting leachable materials from a hydratable polymer by incorporation of an adsorbent into the solution employed to effect extraction. Suitable adsorbents are characterized as having a higher affinity for the leachable materials than either the hydratable polymer or the solvent employed in the solution. Also disclosed are sealed packages comprising an aqueous solution, an adsorbent and a hydratable polymer in the form of an ophthalmic device.
41 Citations
23 Claims
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1. A method for extracting unreacted monomers and partially reacted oligomers from a hydratable xerogel polymer containing said monomers and oligomers wherein said polymer after hydration is in the form of an ophthalmic device which method comprises:
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(a) incorporating an adsorbent into an aqueous solution wherein said absorbent is selected from the group consisting of activated carbon, silica gel and an organic solvent forming a two-phase system with water; and (b) contacting said hydratable xerogel polymer, prior to hydration, with the solution produced in (a) above and maintaining said polymer in such contact under conditions sufficient to reduce the concentration of said monomers and oligomers in said polymer. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for extracting unreacted monomers and partially reacted oligomers from a hydratable xerogel polymer containing said monomers and oligomers and hydrating said polymer wherein said polymer, and hydration, is in the form of an ophthalmic device which method comprises:
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(a) incorporating an absorbent into an aqueous solution wherein said absorbent is selected from the group consisting of activated carbon, silica gel and an organic solvent forming a two-phase system with water; and (b) immersing a hydratable polymer in its xerogel form and prior to hydration thereof into the solution produced in (a) above and maintaining said polymer in said solution under conditions sufficient to reduce the concentration of said monomers and oligomers from said polymer and to hydrate said polymer. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A method for extracting unreacted monomers and partially reacted oligomers from a hydratable xerogel polymer containing said monomers and oligomers wherein said polymer, after hydration, is in the form of an ophthalmic device which method comprises:
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(a) incorporating an adsorbent into an aqueous solution comprising water and a hydratable polymer wherein said polymer, before addition to said water, is in its non-hydrated state and further wherein said absorbent is selected from the group consisting of activated carbon, silica gel and a organic solvent forming a two-phase system with water; and (b) maintaining said polymer in said aqueous solution under conditions sufficient to reduce the concentration of said monomers and oligomers in said polymer. - View Dependent Claims (14, 15, 16, 17, 18)
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- 19. A sealed package comprising an aqueous solution, a hydratable polymer, initially a xerogel in its non-hydrated state which after hydration is in the form of an ophthalmic device, which polymer contains unreacted monomers and partially reacted oligomer contaminants and an adsorbent wherein said package contains sufficient solution to immerse said polymer and further wherein said adsorbent has a higher affinity for said monomer and oligomers than either said polymer or the solution and still further wherein said adsorbent is selected from the group consisting of activated carbon, silica gel and an organic solvent forming a two-phase system with water.
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