Biomedical moldings
AssigneeNovartis AG
InventorLynn Winterton
Life of this patent
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Abstract
The invention relates to a biomedical molding, in particular a contact lens, which is obtainable by crosslinking, in a mold, an aqueous solution of a crosslinkable polyvinyl alcohol (PVA) prepolymer comprising at least 0.5 weight-%, based on the entire formulation, of a non-reactive PVA, wherein the number-average molecular weight of the non-reactive PVA is higher than that of the crosslinkable PVA. A contact lens of the invention has an improved wearing comfort.
Claims20
A biomedical molding which is obtainable by crosslinking in a mold an aqueous solution of a crosslinkable polyvinyl alcohol (PVA) prepolymer comprising at least 0.1 weight-%, based on the entire formulation, of a non-reactive PVA, wherein the number-average molecular weight of the non-reactive PVA is higher than that of the crosslinkable PVA.
The biomedical molding according to claim 2, wherein the crosslinkable PVA is a derivative of a polyvinyl alcohol having an average molecular weight Mn of at least 10000 that, based on the number of hydroxy groups of the polyvinyl alcohol, comprises from approximately 0.5 to approximately 80% of units of formula
- wherein R is C1-C8-alkylene, R2 is hydrogen or C1-C7-alkyl and R2 is an olefinically unsaturated, electron-attracting, copolymerizable radical preferably having up to 25 carbon atoms.
A process for the manufacture of a molding comprising the steps:
- a) preparing an aqueous solution comprising a water-soluble polyvinyl alcohol (PVA) prepolymer having crosslinkable groups and at least 0.1 weight-%, based on the entire formulation, of a non-reactive PVA having a number-average molecular weight, which is higher than that of the PVA prepolymer,
- b) introducing the solution obtained into a mold,
- c) triggering the crosslinking, and
- d) opening the mold such that the molding can be removed from the mold.
Dependencies are inferred from the claim text.