Controlled release subcutaneous implant
First Claim
1. A reservoir device for the sustained administration of a steroid hormone useful for promoting weight gain in livestock, suitable for subcutaneous implantation, which device comprises:
- a) a pellet or plurality of pellets, wherein each pellet comprises1) a steroid hormone in a livestock weight gain-promoting amount,2) a solid hydrophilic polymer in an amount sufficient to cause swelling of said device by osmotic pressure, and3) a solubilizing agent in an amount sufficient to maintain an effective concentration of said steroid hormone in solution within said device, wherein said solubilizing agent is an ionic surfactant having an aliphatic chain of 8 to 22 carbon atoms; and
b) a sufficient amount of a non-porous, rate-controlling membrane which completely encapsulates said pellet or said plurality of pellets, wherein;
1) said membrane is prepared from a material that is selected from the group consisting of an aliphatic polyurethane, an aromatic polyurethane, a silicone rubber, a polyethylene-vinyl acetate copolymer, and a polystyrene-butadiene copolymer; and
2) said membrane is permeable to water and to said steroid hormone, but is impermeable to said solubilizing agent and said hydrophilic polymer.
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Accused Products
Abstract
A sustained release, reservoir-type subcutaneous implant device for the sustained administration to a subject of a biologically active compound comprises:
an effective amount of a biologically active compound;
an amount of a solid hydrophilic polymer sufficient to cause swelling of the device by osmotic pressure after implantation;
an effective amount of a solubilizing agent; and
a sufficient amount of a non-porous rate-controlling membrane which completely encapsulates said biologically active compound, wherein said rate-controlling membrane is permeable to said biologically active compound, but is impermeable to said solubilizing agent. This device is particularly advantageous for the administration of growth promoting compounds to livestock.
252 Citations
29 Claims
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1. A reservoir device for the sustained administration of a steroid hormone useful for promoting weight gain in livestock, suitable for subcutaneous implantation, which device comprises:
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a) a pellet or plurality of pellets, wherein each pellet comprises 1) a steroid hormone in a livestock weight gain-promoting amount, 2) a solid hydrophilic polymer in an amount sufficient to cause swelling of said device by osmotic pressure, and 3) a solubilizing agent in an amount sufficient to maintain an effective concentration of said steroid hormone in solution within said device, wherein said solubilizing agent is an ionic surfactant having an aliphatic chain of 8 to 22 carbon atoms; and b) a sufficient amount of a non-porous, rate-controlling membrane which completely encapsulates said pellet or said plurality of pellets, wherein; 1) said membrane is prepared from a material that is selected from the group consisting of an aliphatic polyurethane, an aromatic polyurethane, a silicone rubber, a polyethylene-vinyl acetate copolymer, and a polystyrene-butadiene copolymer; and 2) said membrane is permeable to water and to said steroid hormone, but is impermeable to said solubilizing agent and said hydrophilic polymer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A method for promoting weight gain and increasing feed efficiency in livestock, which method comprises:
subcutaneously administering a reservoir device which device comprises; a) a pellet or plurality of pellets, wherein each pellet comprises; 1) a steroid hormone in a livestock weight gain-promoting amount, 2) a solid hydrophilic polymer in an amount sufficient to cause swelling of said device by osmotic pressure, and 3) a solubilizing agent in an amount sufficient to maintain an effective concentration of said steroid hormone in solution within said device, wherein said solubilizing agent is an ionic surfactant having an aliphatic chain of 8 to 22 carbon atoms; and b) a sufficient amount of a non-porous, rate-controlling membrane which completely encapsulates said pellet or said plurality of pellets, wherein; 1) said membrane is prepared from a material that is selected from the group consisting of an aliphatic polyurethane, an aromatic polyurethane, a silicone rubber, a polyethylene-vinyl acetate copolymer, and a polystyrene-butadiene copolymer; and 2) said membrane is permeable to water and to said steroid hormone, but is impermeable to said solubilizing agent and said hydrophilic polymer. - View Dependent Claims (29)
Specification