Patent ID: 7056957

Claim:
A method of forming a hydrogel, comprising the steps of: a) combining at least one ethylenically-unsaturated monomer, a cross-linking agent, and an ionic polysaccharide with one or more cations to form a mixture; b) subjecting said mixture to polymerization to form said hydrogel; and c) reacting said hydrogel with one or more cations under equilibrating conditions, wherein i) at least one cation is used that was not used in step a), or ii) if the same mixture of cations is used in steps a) and c), the ratio of cations used in said steps is different; and d) reacting the hydrogel formed in step c) with one or more cations under equilibrating conditions, wherein i) at least one cation is used that was not used in step c), or ii) if the same mixture of cations is used as in step c), the ratio of cations used in said step is different.