Controlled release oxybutynin formulations

Claim 1

A sustained release tablet, comprising: an effective amount of oxybutynin or a pharmaceutically acceptable salt thereof to provide an antispasmodic effect; a sustained release matrix comprising from about 20 to about 60% by weight of a gelling agent comprising a heteropolysaccharide gum and a homopolysaccharide gum capable of cross-linking said heteropolysaccharide gum when exposed to an environmental fluid, the ratio of said heteropolysaccharide gum to said homopolysaccharide gum being from about 1:3 to about 3:1; an effective amount of a pharmaceutically acceptable cationic cross-linking agent selected from the group consisting of alkali metal and alkaline earth metal sulfates, chlorides, borates, bromides, citrates, acetates, lactates and mixtures thereof, capable of crosslinking with said gelling agent and increasing the gel strength when the dosage form is exposed to an environmental fluid; and an inert pharmaceutical diluent selected from the group consisting of monosaccharide, a disaccharide, a polyhydric alcohol, and mixtures thereof, the ratio of said oxybutynin to said gelling agent being from about 1:2 to about 1:25; said dosage form providing a sustained release of said oxybutynin when exposed to an environmental fluid.

Claim 15

A method of preparing a solid oral sustained release formulation of oxybutynin, comprising: preparing a sustained release matrix comprising from about 20 to about 60 percent by weight of a gelling agent comprising a heteropolysaccharide gum and a homopolysaccharide gum capable of cross-linking said heteropolysaccharide gum when exposed to an environmental fluid, the ratio of said heteropolysaccharide gum to said homopolysaccharide gum being from about 1:3 to about 3:1, a cationic crosslinking agent selected from the group consisting of alkali metal and alkaline earth metal sulfates, chlorides, borates, bromides, citrates, acetates, lactates and mixtures thereof, in an amount effective to crosslink with said gelling agent and increase the gel strength when exposed to an environmental fluid, and an inert diluent, mixing said sustained release matrix with oxybutynin or a pharmaceutically acceptable salt thereof, such that the ratio of oxybutynin to gelling agent is from about 1:2 to about 1:25 by weight, and compressing said mixture of sustained release matrix and oxybutynin into tablets having an amount of oxybutynin necessary to render an antispasmodic effect, said tablets providing a sustained release of oxybutynin for about 24 hours when exposed to an environmental fluid.

Claim 16

A method of preparing a solid oral sustained release formulation of oxybutynin, comprising: preparing a sustained release matrix comprising from about 20 to about 60 percent by weight of a gelling agent comprising a heteropolysaccharide gum and a homopolysaccharide gum capable of cross-linking said heteropolysaccharide gum when exposed to an environmental fluid, the ratio of said heteropolysaccharide gum to said homopolysaccharide gum being from about 1:3 to about 3:1, a cationic crosslinking agent selected from the group consisting of alkali metal and alkaline earth metal sulfates, chlorides, borates, bromides, citrates, acetates, lactates and mixtures thereof, in an amount effective to crosslink with said gelling agent and increase the gel strength when exposed to an environmental fluid, and an inert diluent, mixing said sustained release matrix with oxybutynin or a pharmaceutically acceptable salt thereof, such that the ratio of oxybutynin to gelling agent is from about 1:2 to about 1:25 by weight, and compressing said mixture of sustained release matrix and oxybutynin into tablets having an amount of oxybutynin necessary to render an antispasmodic effect, said tablets providing a sustained release of oxybutynin for about 24 hours when exposed to an environmental fluid.

Claim 20

A method of treating a patient with oxybutynin, comprising preparing a sustained release matrix comprising from about 20 to about 60 percent by weight of a gelling agent comprising a heteropolysaccharide gum and a homopolysaccharide gum capable of cross-linking said heteropolysaccharide gum when exposed to an environmental fluid, the ratio of said heteropolysaccharide gum to said homopolysaccharide gum being from about 1:3 to about 3:1, a cationic crosslinking agent selected from the group consisting of alkali metal and alkaline earth metal sulfates, chlorides, borates, bromides, citrates, acetates, lactates and mixtures thereof, in an amount effective to crosslink with said gelling agent and increase the gel strength of the formulation when it is exposed to gastrointestinal fluid, and an inert diluent, mixing said sustained release matrix with oxybutynin or a pharmaceutically acceptable salt thereof, such that the ratio of oxybutynin to gelling agent is from about 1:2 to about 1:25 by weight, compressing said mixture of sustained release matrix and oxybutynin into tablets having an amount of oxybutynin necessary to render an antispasmodic effect, said tablets providing a sustained release of oxybutynin for about 24 hours when exposed to gastrointestinal fluid, and administering said tablets to a human patient in 24 hour intervals.

Claim 21

A method of treating a patient with oxybutynin, comprising preparing a sustained release matrix comprising from about 20 to about 60 percent by weight of a gelling agent comprising a heteropolysaccharide gum and a homopolysaccharide gum capable of cross-linking said heteropolysaccharide gum when exposed to an environmental fluid, the ratio of said heteropolysaccharide gum to said homopolysaccharide gum being from about 1:3 to about 3:1, a cationic crosslinking agent selected from the group consisting of alkali metal and alkaline earth metal sulfates, chlorides, borates, bromides, citrates, acetates, lactates and mixtures thereof, in an amount effective to crosslink with said gelling agent and increase the gel strength of the formulation when it is exposed to gastrointestinal fluid, and an inert diluent, mixing said sustained release matrix with oxybutynin or a pharmaceutically acceptable salt thereof, such that the ratio of oxybutynin to gelling agent is from about 1:2 to about 1:25 by weight, compressing said mixture of sustained release matrix and oxybutynin into tablets having an amount of oxybutynin necessary to render an antispasmodic effect, said tablets providing a sustained release of oxybutynin for about 24 hours when exposed to gastrointestinal fluid, and administering said tablets to a human patient in 24 hour intervals.