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Drug delivery system and method of making the same

  • US 4,897,268 A
  • Filed: 08/03/1987
  • Issued: 01/30/1990
  • Est. Priority Date: 08/03/1987
  • Status: Expired due to Term
First Claim
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1. A method of preparing a composition for delivering a an effective amount of a constant dose of an active ingredient to an animal over a preselected, prolonged period of time, comprising the steps of:

  • (a) encapsulating effective amounts of said ingredient in first and second separate biodegradable and biocompatible copolymer excipients having different monomers ratios to form first and second microcapsules, each of said microcapsules having of a different rate of release therefrom of said ingredient; and

    (b) combining an effective amount of said first and second microcapsules to form said composition having a delivery profile wherein the release of said ingredient through said second microcapsule begins as the release of said ingredient through said first microcapsule declines.

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