Stabilized controlled release substrate having a coating derived from an aqueous dispersion of hydrophobic polymer
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Abstract
A stabilized solid cqntrolled release dosage form having a coating derived from an aqueous dispersion of ethylcellulose is obtained by overcoating a substrate including a therapeutically active with an aqueous dispersion of ethylcellulose and then curing the coated substrate at a temperature and relative humidity elevated to a suitable level above ambient conditions until the coated dosage form attains a stabilized dissolution profile substantially unaffected by exposure to storage conditions of elevated temperature and/or elevated relative humidity.
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Citations
74 Claims
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1-38. -38. (Canceled)
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39. A controlled release layered bead for inclusion in an oral controlled release pharmaceutical formulation comprising:
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an inert bead coated with a therapeutically active agent, a barrier layer over said bead coated with said therapeutically active agent, said barrier layer comprising hydroxypropylmethylcellulose, a controlled release layer over said barrier layer, said controlled release layer derived from an aqueous dispersion of plasticized ethylcellulose in an amount sufficient to obtain a controlled release of said analgesic when said formulation is exposed to an environmental fluid, said controlled release layered bead being cured to a temperature greater than the glass transition temperature of the plasticized ethylcellulose for at least about 24 hours. - View Dependent Claims (40, 41, 42, 43, 44, 45, 46, 47, 48)
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49. A method for preparing a controlled release layered bead for inclusion in an oral controlled release formulation of a therapeutically active agent, comprising:
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coating a pharmaceutically acceptable inert bead with a therapeutically active agent;
thereafter coating said bead with a barrier layer comprising hydroxypropylmethylcellulose;
thereafter applying a controlled release layer onto said bead, said controlled release layer comprising a sufficient amount of a plasticized ethylcellulose to obtain a predetermined controlled release of said therapeutically active agent when said coated bead is exposed to an environmental fluid, said plasticized ethylcellulose being applied to said bead as an aqueous dispersion; and
curing said controlled release layered beads at a temperature greater than the glass transition temperature of the plasticized ethylcellulose for at least 24 hours. - View Dependent Claims (50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62)
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63. A controlled release layered bead for inclusion in a controlled release formulation, comprising
a pharmaceutically acceptable inert bead coated with a therapeutically active agent, said bead coated with said therapeutically active agent being overcoated with a barrier layer comprising hydroxypropylmethylcellulose, said barrier coated bead being coated with a controlled release layer derived from an aqueous dispersion of plasticized ethylcellulose in an amount sufficient to obtain a controlled release of said therapeutically active agent when said bead is exposed to a gastrointestinal fluid, said coated bead being cured at a temperature greater than the glass transition temperature of the plasticized ethylcellulose for at least about 24 hours, to cause individual ethylcellulose particles in said coating to coalesce and to gradually slow the release of said analgesic when said bead is exposed to aqueous fluid, until an endpoint is reached at which said cured coated bead, when subjected to in-vitro dissolution, releases said therapeutically active agent in amounts which do not vary at any time point along the dissolution curve by more than about 20% of the total amount of therapeutically active agent released, when compared to the in-vitro dissolution of said coated bead prior to curing.
Specification