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Polymer release system

  • US 9,694,080 B2
  • Filed: 08/23/2013
  • Issued: 07/04/2017
  • Est. Priority Date: 09/21/2001
  • Status: Expired due to Fees
First Claim
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1. A pharmaceutical composition for controlled release of at least one therapeutically active substance into an aqueous medium by erosion of at least one surface of the composition, wherein:

  • the composition is provided in a dosage form consisting of a single erodible matrix having a coating, wherein;

    the single erodible matrix comprises;

    (a) one or more polyethylene oxides, wherein the average molecular weight of the one or more polyethylene oxides present in the matrix is from about 200,000 daltons to about 400,000 daltons,(b) a block copolymer of ethylene oxide and propylene oxide,(c) a therapeutically active substance, and,(d) one or more pharmaceutically acceptable excipients selected from the group consisting of cellulose derivatives, release modifiers, and antioxidants, andthe coating has at least one opening exposing at least one surface of said matrix, the coating being insoluble in and impermeable to body fluids,wherein any matrix surface exposed to an aqueous medium erodes at a substantially constant rate, so that a zero order release is obtained of at least about 60% w/w of the active substance from the pharmaceutical composition over a time period of at least 4 hours when subject to an in vitro dissolution test according to USP 24, NF 19, 711 Dissolution, employing Apparatus 2 equipped with a paddle and wherein aqueous medium is able to diffuse into the matrix with a diffusion rate of 100±

    30% of the dissolution rate of the matrix in aqueous medium when tested according to USP 24, page 1941-1950.

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