Sustained-release formulations

Claim 1

A sustained-release formulation of a pharmacologically active substance presented in the form of a tablet of sufficient granules to provide at least one predetermined dose of the pharmacologically active substance and effervescent or water-dispersible ingredients, each of said granules having a diameter of between about 0.5 and 2.5 mm and comprising: a) a core comprising at least one pharmacologically active substance and at least one excipient; b) a coating covering substantially the whole surface of the core and comprising about 100 parts of a water insoluble but water swellable neutral copolymer of ethyl acrylate and methyl methacrylate and from about 20 to 70 parts of a water soluble hydroxylated cellulose derivative, the weight of the coating being from about 2 to 25% of the weight of the core, and c) said tablet being adapted to substantially disintegrate into said granules upon being brought into contact with an aqueous liquid prior to being swallowed.

Claim 9

A method for preparing a sustained-release formulation of a pharmacologically active substance presented in the form of an effervescent or water-dispersible tablet of sufficient granules to provide at least one predetermined dose of the pharmacologically active substance and effervescent or water-dispersible ingredients, each of said granules having a diameter of between about 0.5 and 2.5 mm and comprising: a) a core comprising at least one pharmacologically active substance and at least one excipient; and b) a coating covering substantially the whole surface of the core and comprising about 100 parts of a water insoluble but water swellable neutral copolymer of ethyl acrylate and methyl methacrylate and from about 20 to 70 parts of a water soluble hydroxylated cellulose derivative, the weight of the coating being from about 2 to 25% of the weight of the core, and c) said tablet being adapted to substantially disintegrate into said granules upon being brought into contact with an aqueous liquid prior to being swallowed, said method comprising: i) mixing at least one pharmacologically active substance with at least one excipient; ii) forming the mixture into core particles; iii) forming a suspension comprising about 100 parts of a water insoluble but water swellable acrylic polymer and from about 20 to 70 parts of a water soluble hydroxylated cellulose derivative; iv) coating the said core particles with the said suspension to form granules having a diameter of between about 0.5 and 2.5 mm, the weight of the coating being from about 2 to 25% of the weight of the core; and v) compressing a sufficient amount of the granules to provide at least one predetermined dose of the pharmacologically active substance, together with effervescent or water-dispersible ingredients, to form said effervescent or water-dispersible tablet.

Claim 10

A method for preparing a sustained-release formulation of a pharmacologically active substance presented in the form of an effervescent or water-dispersible tablet of sufficient granules to provide at least one predetermined dose of the pharmacologically active substance and effervescent or water-dispersible ingredients, each of said granules having a diameter of between about 0.5 and 2.5 mm and comprising: a) a core comprising at least one pharmacologically active substance and at least one excipient; and b) a coating covering substantially the whole surface of the core and comprising about 100 parts of a water insoluble but water swellable neutral copolymer of ethyl acrylate and methyl methacrylate and from about 20 to 70 parts of a water soluble hydroxylated cellulose derivative, the weight of the coating being from about 2 to 25% of the weight of the core, and c) said tablet being adapted to substantially disintegrate into said granules upon being brought into contact with an aqueous liquid prior to being swallowed, said method comprising: i) mixing at least one pharmacologically active substance with at least one excipient; ii) forming the mixture into core particles; iii) forming a suspension comprising about 100 parts of a water insoluble but water swellable acrylic polymer and from about 20 to 70 parts of a water soluble hydroxylated cellulose derivative; iv) coating the said core particles with the said suspension to form granules having a diameter of between about 0.5 and 2.5 mm, the weight of the coating being from about 2 to 25% of the weight of the core; and v) compressing a sufficient amount of the granules to provide at least one predetermined dose of the pharmacologically active substance, together with effervescent or water-dispersible ingredients, to form said effervescent or water-dispersible tablet.