Delivery system
First Claim
1. A device for the controlled and continuous administration of a chemical to an aqueous liquid-containing environment over a prolonged period of time, said device comprising a reservoir containing said chemical, a shaped wall formed in part at least of a porous material, said porous material being in contact with at least a part of said reservoir and being insoluble in said environment while maintaining its integrity during said prolonged period of time, and a hydrogel medium means impregnating the pores of said porous material, said hydrogel medium means having channels or pores which (1) permit the diffussion of aqueous liquid from said environment into said reservoir to form a solution of said chemical in said aqueous liquid and (2) permit the diffussion of said solution containing said chemical to said environment, the dissolved chemical so released being replaced by the continuous dissolving of said chemical in said reservoir and the amount of dissolved chemical in said reservoir changing continuously throughout said prolonged period of time so as to maintain the rate of chemical release to said environment substantially constant during a substantial portion of said prolonged period of time.
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Accused Products
Abstract
Delivery systems and devices for the controlled release of chemicals, including drugs, comprising a wall, formed in part at least, of a porous material, pores of which contain a hydrogel, said porous wall in contact with at least a portion of a reservoir comprised of a chemical and, if desired, a water-soluble liquid excipient and/or a detergent; process for preparation thereof, and use for the controlled release of chemicals, including drugs, to an aqueous liquid-containing environment. Emphasis is given to said systems and devices in which the porous material is a sintered plastic and gelled cellulose triacetate is the hydrogel, and to their use for controlled release of drugs to animals, especially to ruminants over prolonged periods of time.
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Citations
38 Claims
- 1. A device for the controlled and continuous administration of a chemical to an aqueous liquid-containing environment over a prolonged period of time, said device comprising a reservoir containing said chemical, a shaped wall formed in part at least of a porous material, said porous material being in contact with at least a part of said reservoir and being insoluble in said environment while maintaining its integrity during said prolonged period of time, and a hydrogel medium means impregnating the pores of said porous material, said hydrogel medium means having channels or pores which (1) permit the diffussion of aqueous liquid from said environment into said reservoir to form a solution of said chemical in said aqueous liquid and (2) permit the diffussion of said solution containing said chemical to said environment, the dissolved chemical so released being replaced by the continuous dissolving of said chemical in said reservoir and the amount of dissolved chemical in said reservoir changing continuously throughout said prolonged period of time so as to maintain the rate of chemical release to said environment substantially constant during a substantial portion of said prolonged period of time.
- 22. A method for the control of helminthiasis in ruminant animals which comprises administering to said animals for retention in the rumeno-reticular sac, a device for the controlled and continuous administration of a water soluble salt of morantel to the aqueous liquid-containing environment in said rumeno-reticular sac over a prolonged period of time, said device comprising a reservoir containing said morantel, a shaped wall formed in part at least of a porous material, pores of which contain a hydrogel medium, said porous wall in contact with at least a part of said reservoir and characterized by being insoluble in said environment and maintaining its integrity during said prolonged period of time, said hydrogel being permeable to passage of said morantel and to said aqueous liquid so that said device when placed in said environment continuously releases said morantel from said reservoir to said environment at a physiologically effective controlled rate through said medium, the dissolved morantel so released being replaced by the continuous dissolving of said morantel in said reservoir, the amount of dissolved morantel in said reservoir changing continuously throughout said prolonged time period, so as to maintain the rate of morantel release to said environment substantially constant during a substantial portion of said prolonged time period.
- 36. A method for the control of helminths on pasture land, the helminth larvae contamination of which is at or near a minimum level, which comprises grazing on said land ruminant animals having in their rumeno-reticular sacs, a device for the controlled and continuous administration of a water soluble salt of morantel to the aqueous liquid-containing environment in said rumeno-reticular sac over a prolonged period of time, said device comprising a reservoir containing said morantel, a shaped wall formed in part at least of a porous material, pores of which contain a hydrogel medium, said porous wall in contact with at least a part of said reservoir and characterized by being insoluble in said environment and maintaining its integrity during said prolonged period of time, said hydrogel being permeable to passage of said morantel and to said aqueous liquid so that said device when placed in said environment continuously releases said morantel from said reservoir to said environment at a physiologically effective controlled rate through said medium, the dissolved morantel so released being replaced by the continuous dissolving of said morantel in said reservoir, the amount of dissolved morantel in said reservoir changing continuously throughout said prolonged time period, so as to maintain the rate of morantel release to said environment substantially constant during a substantial portion of said prolonged time period.
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38. A method for the control of lung worm infections in ruminant animals which comprises administering to said animals for retention in the rumeno-reticular sac, a device for the controlled and continuous administration of a water soluble salt of morantel to the aqueous liquid-containing environment in said rumeno-reticular sac over a prolonged period of time, said device comprising a reservoir containing said morantel, a shaped wall formed in part at least of a porous material, pores of which contain a hydrogel medium, said porous wall in contact with at least a part of said reservoir and characterized by being insoluble in said environment and maintaining its integrity during said prolonged period of time, said hydrogel being permeable to passage of said morantel and to said aqueous liquid so that said device when placed in said environment continuously releases said morantel from said reservoir to said environment at a physiologically effective controlled rate through said medium, the dissolved morantel so released being replaced by the continuous dissolving of said morantel in said reservoir, the amount of dissolved morantel in said reservoir changing continuously throughout said prolonged time period, so as to maintain the rate of morantel release to said environment substantially constant during a substantial portion of said prolonged time period.
Specification