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Polymeric particles having a biodegradable gelatin or aminodextran coating and processes for making same

  • US 5,776,706 A
  • Filed: 03/06/1997
  • Issued: 07/07/1998
  • Est. Priority Date: 10/31/1990
  • Status: Expired due to Fees
First Claim
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1. A process for the preparation of colloidal particles having (A) a hydrophobic non-gelatin, non-aminodextran polymeric core coated with a substance selected from the group consisting of type A, acid cured gelatin of Bloom in the range 60 to 300 and an aminodextran having a molecular weight in the range of 10,000 to 2 million, and (B) a plurality of functional groups pendent from said gelatin or aminodextran coating, said process comprising:

  • (a) coating said gelatin or aminodextran onto the surface of a polymeric core selected from the group consisting of a polymeric substance having amine-reactive functional groups and a polymeric core not having amine-reactive functional groups, said coating being by the method of;

    (i) adsorbing said gelatin or aminodextran onto the surface of said core or(ii) convalently coupling said aminodextran to said core by reaction of aminodextran amine groups and said amine-reactive groups present on said core;

    (b) (i) crosslinking the gelatin or aminodextran coating of step (a) (i) by reaction of said coating with a chemical crosslinking agent, or(ii) selectively crosslinking or not crosslinking the aminodextran coating of step (a) (ii), said crosslinking being by reaction of said coating with a chemical crosslinking agent;

    (c) blocking free, unreacted crosslinking agent functional groups present on the surface of any step (b) crosslinked product by reaction of said groups with a polyamine such that at least one polyamine --NH2 group reacts with the unreacted crosslinking agent functional groups and at least one polyamine --NH2 group remains unreacted; and

    (d) washing the particles of step (c) or the uncrosslinked particles of step (b) (ii) to obtain colloidal particles having a solid polymer core coated with gelatin or aminodextran and having pendent amine groups.

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