초록 ▼

Delivery systems and devices for the controlled release of chemicals, including drugs, comprising a wall, formed in part at least, of a porous fabric 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 desire

Delivery systems and devices for the controlled release of chemicals, including drugs, comprising a wall, formed in part at least, of a porous fabric 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 fabric material is a synthetic fabric 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.

대표청구항 ▼

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 mate

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.