초록

A pouch for the controlled release of active ingredients into an aqueous medium comprising liquid or solid active ingredients enclosed in a sealed envelope of cold water-insoluble polyvinyl alcohol.

대표청구항 ▼

A method for the controlled release of active ingredient into an aqueous medium having a maximum temperature of 60°C. consisting of the steps of (1) preparing a sealed pouch of cold water-insoluble polyvinyl alcohol in film form, said polyvinyl alcohol being at least about 99% hydrolyzed and having

A method for the controlled release of active ingredient into an aqueous medium having a maximum temperature of 60°C. consisting of the steps of (1) preparing a sealed pouch of cold water-insoluble polyvinyl alcohol in film form, said polyvinyl alcohol being at least about 99% hydrolyzed and having a minimum degree of swelling in water of about 120%, and enclosed therein an effective amount of an active ingredient having at least a minimum solubility in water; said sealed pouch having a maximum ratio of weight of active ingredient to pouch volume of about 50 lb/ft3; (2) introducing said sealed pouch into said aqueous medium; (3) swelling said polyvinyl alcohol film; (4) introducing the aqueous medium into said pouch to dissolve said active ingredient; the aqueous medium containing said active ingredient having a pH in the range of 2.5-10.0; and (5) allowing said active ingredient to diffuse through said swollen film and be released into said aqueous medium.