Controlled release delivery system

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 fabric material, said porous fabric 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 fabric material, said hydrogel medium means having channels or pores which (1) permit the diffusion 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.

Claim 2

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 fabric material, said porous fabric 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 fabric material, said hydrogel medium means having channels or pores which (1) permit the diffusion 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.

Claim 5

A device according to claims 1 or 2 wherein said porous fabric material selected from the group consisting of poly(ethylene), poly(propylene), poly(tetrafluoroethylene), glass, nylon, cotton, and modacrylic.

Claim 6

A device according to claims 1 or 2 wherein the aqueous liquid containing environment is an animal body site.

Claim 14

A device according to claims 1 or 2 wherein said device contains a high density material in such quantity that the device has a density of at least 2.0.

Claim 23

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 fabric material, pores of which contain a hydrogel medium, said porous fabric wall to 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 medium 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.

Claim 24

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 fabric material, pores of which contain a hydrogel medium, said porous fabric wall to 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 medium 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.

Claim 27

A method according to claims 22 or 23 wherein said porous fabric material is selected from the group consisting of poly(ethylene), poly(propylene), poly(tetrafluoroethylene), glass and modacrylic.

Claim 32

A method according to claims 22 or 23 wherein said device contains a high density material in such quantity that the device has a density of at least 2.0.

Claim 38

A method for the control of helminths on pasture land, the helminth larval 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 fabric 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.

Claim 39

A method for the control of helminths on pasture land, the helminth larval 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 fabric 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.

Claim 41

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 fabric material, said porous fabric 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 medium 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.

Claim 42

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 fabric material, said porous fabric 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 medium 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.