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Hydrogel compositions demonstrating phase separation on contact with aqueous media

  • US 8,541,021 B2
  • Filed: 05/17/2004
  • Issued: 09/24/2013
  • Est. Priority Date: 05/01/2001
  • Status: Expired due to Term
First Claim
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1. A body surface contacting composition comprising:

  • (a) a first water-swellable acrylate-based polymer having a pH-dependent solubility and insoluble in water at a pH less than about 5.5,(b) a blend of a poly(N-vinyl lactam) and a complementary oligomer capable of hydrogen bonding to the poly(N-vinyl lactam); and

    (c) a second water-swellable acrylate-based polymer that is insoluble in water independent of pH;

    in a solvent or mixture of solvents,wherein the weight ratio of the first to second water-swellable acrylate-based polymers is in a range of about 1.5;

    1 to 2;

    1 and the poly(N-vinyl lactam) represents about 1-30 weight percent of the composition, such that when the composition is placed in an aqueous environment at a pH of from about 6-8, the second water-swellable acrylate-based polymer forms a film over the remainder of the composition.

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