compound that tends to shrink or constrict body tissues and precipitate the protein, and astringent forms a protective layer on the surface.
– Due to their protein action, astringents can reduce cell permeability.
– This reduces local edema, exudation, and inflammation.
– The word “astringent” derives from the Latin “adstringere”, meaning “to bind fast”.
– They are usually applied topically to damaged skin or the mucous membrane of GIT, including the mouth.
Characteristics
– Affect only the superficial layer. Reduce cellular permeability.
– Make the surface mechanically strong and decrease exudation.
– Protect from external irritation.
– Possess local styptic and local antiseptic action.
– May interfere with the function of pain receptors. The pain-relieving action is mild.
– Constrict the blood vessels to stop bleeding.
Types of Astringents
1) Vegetable astringents: Tannic acid, Gallic acid
2) Metallic Astringents:
Aluminium salts: Alum [KAl(SO4)2•12H2O], Aluminium chloride (AlCl3), Aluminum acetate
Zinc salts: Zinc chloride (ZnCl2), Zinc sulfate (ZnSO4)
Ferric chloride (FeCl3)
Strontium chloride
Silver nitrate (AgNO3)
Copper sulfate (CuSO4) 3) Miscellaneous: Very cold water, Alcohol
Indications
Swollen, inflamed, and/or leaky tissues.
They are used to treat diarrhea or dysentery.
During leukorrhea (thick white/yellowish vaginal discharge)
During minor bleeding like Menorrhagia, Hemorrhoids.
They promote the healing process.
They decrease sweating and possess deodorant properties.
Mild astringent solutions relieve minor skin irritations from superficial cuts, allergies, insect bites, or fungal infections such as athlete’s foot.
