A foam is a coarse dispersion of a gas in a liquid which is present as thin films or lamellae of colloidal dimensions between the gas bubbles.
Foams find application in pharmacy as aqueous and non-aqueous spray preparations for topical, rectal and vaginal medications and for burn dressings. Equally important, however, is the destruction of foams and the use of antifoaming agents. These are important in manufacturing processes, preventing foam in liquid preparations, for example. In addition, foam inhibitors such as the silicones are used in the treatment of flatulence, for the elimination of gas, air or foam from the gastrointestinal tract prior to radiography, and for the relief of abdominal distension and dyspepsia.