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Controlled release formulations coated with aqueous dispersions of acrylic polymers

  • US 5,639,476 A
  • Filed: 06/02/1995
  • Issued: 06/17/1997
  • Est. Priority Date: 01/27/1992
  • Status: Expired due to Term
First Claim
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1. A controlled release dosage form, comprising a substrate containing an active agent in an amount sufficient to provide a desired effect, said substrate being coated with a plasticized aqueous dispersion consisting essentially of ammonio-methacrylate copolymers which are copolymerizates of acrylic acid and methacrylic acid esters having a low content of quarternary ammonium groups and a further material selected from the group consisting of a polymerizable permeability-enhancing agent, a water-soluble acrylic polymer, a pore-former, and mixtures of any of the foregoing, said dispersion containing no significant amount of other coating polymers,said coating being applied to said substrate in an amount sufficient to obtain a controlled release of said active agent when said coated substrate is exposed to an environmental fluid, andsaid coated substrate being cured at a temperature greater than the glass transition temperature of the aqueous dispersion of said plasticized water-insoluble acrylic polymer, for about 24 to about 60 hours until a curing endpoint is reached at which said cured coated substrate provides a stabilized dissolution of said active agent which is unchanged after exposure to accelerated storage conditions,said curing endpoint being determined by comparing the dissolution profile of the dosage form immediately after curing to the dissolution profile of the formulation after exposure to accelerated storage conditions of at least one month at a temperature of 40°

  • C. and at a relative humidity of 75% and said active agent is released in an amount which does not vary at any given dissolution time point by more than about 15% of the total amount of therapeutically active agent released, when compared to in-vitro dissolution of said coated substrate prior to storage.

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