Products
Boric acid is contained in eye drops as an excipient. In Germany, it belongs to the so-called “questionable prescription drugs” and should be used exclusively for healing waters and buffers in eye drops and for homeopathics (from D4). This is justified by a lack of efficacy and the risk of resorptive poisoning. This requirement also applies to the esters and salts of boric acid, for example borax. Furthermore, it must be noted that boric acid may not be sold as a pure substance to private individuals in many countries.
Structure and properties
Boric acid (H3BO3, Mr = 61.8 g/mol) is present as colorless, shiny, greasy-feeling scales, as white crystals, or as a white crystalline powder. It is odorless, soluble in water and dissolves readily in boiling water. Boric acid is a weak inorganic acid.
Effects
Boric acid (ATC S02AA03) has antiseptic, antibacterial, and antifungal properties.
Indications for use
Boric acid is used as a pharmaceutical excipient primarily for eye drops. It has preservative effects and serves as a buffer for pH adjustment. Because of the potential risks (see below), boric acid is now used with medical restraint or is no longer used. Former uses include:
- For topical treatment of vaginal fungus, see Boric acid for vaginal fungus.
- Vaginal infections.
- As a disinfectant.
Adverse effects
In animal studies, boric acid has been found to impair reproductive function and to have fertility-damaging (teratogenic) properties. Because similar effects could occur in humans, boric acid is classified accordingly.
