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Dispensing system with means for increasing delivery of beneficial agent from the system

  • US 4,844,984 A
  • Filed: 03/24/1988
  • Issued: 07/04/1989
  • Est. Priority Date: 03/19/1984
  • Status: Expired due to Term
First Claim
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1. A delivery device for delivering a beneficial agent to a ruminant, the delivery device comprising:

  • (a) wall means that surrounds and forms an internal lumen, said wall means comprising in at least a part a semipermeable composition permeable to fluid present in the ruminant and substantially impermeable to the passage of a beneficial agent, and wherein the lumen comprises;

    (b) means for maintaining the delivery system in the environment over a period of time, said means having a density greater than the density of a fluid present in the ruminant;

    (c) means for absorbing thermal energy from the ruminant for forming a dispensable composition, said means comprising a member selected from the group consisting of a glyceride of a fatty acid having a melting point of at least 31°

    C., a block copolymer of 1,2-butylene oxide and ethylene oxide, a food grade wax having a melting point of at least 35°

    C., a thermo-responsive lipophilic pharmaceutically acceptable carrier, a thermo-responsive hydrophobic pharmaceutically acceptable carrier, propylene glycol monostearate, propylene glycol distearate, triglyceride of saturated vegetable fatty acid, polyethylene glycol monostearate, a food grade petroleum wax, and a mixture of cocoa butter and beeswax;

    (d) a beneficial agent present in the means for absorbing thermal energy;

    (e) means for swelling and occupying a larger volume of the lumen for applying force against the means for absorbing thermal energy for pushing said means that absorb energy from the delivery device, said means for occupying a larger volume comprising a member selected from the group consisting of a hydrogel, poly(ethylene oxide), poly(acrylamide), poly(hydroxyalkyl acrylate), poly(acrylic acid), polysaccharide, and the sodium salt of polyacrylic acid blended with sodium chloride;

    (f) means for lessening the partition of a beneficial agent from the means for absorbing thermal energy into the means for occupying a larger volume, said means for lessening the partitions located between the means for absorbing energy and the means for occupying volume; and

    ,(g) at least one exit means in the wall for releasing a beneficial agent formulation from the delivery device to the ruminant over time.

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