Products
Foams are commercially available as pharmaceuticals, cosmetics (personal care products), medical devices, and foods. Some examples are listed below:
- Rectal foam containing budesonide or mesalazine for inflammatory bowel disease (ulcerative colitis of the rectum).
- Glucocorticoids and calcipotriol in psoriasis of the skin or scalp.
- Minoxidil for the treatment of androgenetic hair loss.
No drugs:
- Dexpanthenol foam for sunburn.
- Shaving foam
- Cleansing foam, shower foam, washing foam
- Skin care and cooling foams
- Hair mousse
Structure and properties
In pharmacy, foams are preparations in which a large volume of gas is dispersed in a liquid phase (dispersion). The gas forms small bubbles or cells and is surrounded by liquid. Foams can contain active pharmaceutical ingredients. As already mentioned, there are also cosmetics or medical products which are free of active ingredients. A surface-active substance (an emulsifier such as cetylstearyl alcohol or a polysorbate) enables foam formation. This usually occurs in a pressurized container of a liquid preparation and only during application. The gas is a blowing agent such as butane, isobutane, propane, 2-methylpropane or dimethyl ether.
Effects
Foams have a light consistency and are readily absorbed. They have cooling, hydrating, skin-conditioning, soothing, and partially cleansing properties. Foams spread well over large areas of the skin or hair.
Areas of application
Foams are usually applied locally to the skin or mucous membrane.
Adverse effects
Drug containers are usually pressurized and some contain flammable propellants. They must be kept away from sources of ignition and from direct sunlight. Do not store in refrigerator or freeze. Do not force open, drill into, or incinerate empty containers.
