Stabilized controlled release formulations having acrylic polymer coating

A stabilized controlled release solid dosage form for release of a dose of a therapeutically active agent comprising a substrate comprising a therapeutically active agent, said substrate overcoated with an aqueous dispersion consisting essentially of a plasticized copolymer of acrylic and methacrylic acid esters having a permeability which is unaffected by the pH conditions prevailing in the digestive tract, in an amount sufficient to provide a controlled release of said dose of therapeutically active agent in the gastrointestinal tract, said coated substrate being cured at a temperature greater than the glass transition temperature of the aqueous dispersion of the plasticized acrylic polymer for at least about 24 hours, until an endpoint is reached at which the coated substrate provides a stable dissolution profile, said endpoint being determined by comparing the dissolution profile of the formulation immediately after curing to the dissolution profile of the formulation after exposure to accelerated conditions of one month at a temperature of 37.degree. C. and at a relative humidity of 80%.

A stabilized solid controlled release dosage form comprising a substrate comprising a therapeutically active agent, said substrate overcoated with a controlled release coating derived from an aqueous dispersion consisting essentially of a plasticized ammonio methacrylate copolymer, said ammonio methacrylate copolymer which is a copolymerizate of acrylic and methacrylic esters having a low content of quaternary ammonium groups being included in said coating in an amount sufficient to provide a controlled release of said therapeutically active agent in the gastrointestinal tract, said ammonio methacrylate copolymer having a permeability which is unaffected by the pH conditions prevailing in the gastrointestinal tract, said coated substrate being cured at a temperature above the glass transition temperature of the plasticized ammonio methacrylate copolymer for at least about 24 hours for a time period necessary to obtain a final product which provides a stable in-vitro release of said therapeutically active agent when exposed to accelerated storage conditions of one month at 37.degree. C. and 80% relative humidity.

A stabilized controlled release solid dosage form for release of a dose of a therapeutically active agent, comprising a substrate comprising a therapeutically active agent, said substrate overcoated with a controlled release coating of an aqueous dispersion of a plasticized ammonio methacrylate copolymers which are copolymerizates of acrylic and methacrylic esters having a low content of quaternary ammonium groups in an amount sufficient to provide release of said dose of therapeutically active agent in the gastrointestinal tract, said ammonio methacrylate copolymer having a permeability which is unaffected by the pH conditions prevailing in the gastrointestinal tract, said acrylic polymer being cured at a temperature greater than the glass transition temperature of the aqueous dispersion of the plasticized acrylic polymer for at least about 24 hours until an endpoint is reached such that a final product is obtained which provides a reproducible, stabilized dissolution profile, said endpoint being determined by comparing the dissolution profile of the formulation immediately after curing to the dissolution profile of the formulation after exposure to accelerated conditions of one month at a temperature of 37.degree. C. and at a relative humidity of 80%.