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Method for inducing crystalline state transition in medicinal substance

  • US 5,811,547 A
  • Filed: 06/09/1995
  • Issued: 09/22/1998
  • Est. Priority Date: 10/14/1992
  • Status: Expired due to Fees
First Claim
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1. A method for inducing a transition from a first crystalline state to a second crystalline state in a crystallizable medicinal substance, said method comprising the steps of:

  • a) feeding said substance, in the first crystalline state, into extruder means having at least two separate temperature zones, maintained at differing temperatures, with a first of said zones being maintained in a temperature range sufficient to melt the medicinal substance in the first crystalline state but below a decomposition temperature thereof, and with the second of said temperature zones being maintained in a temperature range below that of the first zone and at a level whereby the second crystalline state of the material is induced;

    b) melting the substance in the first crystalline state in said first zone and continuously moving the melted substance from the first zone to the second zone;

    c) inducing the second crystalline state in the crystallizable substance in said second zone; and

    d) extruding the substance, in said second crystalline state, from the extruder means.

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