BENZALKONIUM CHLORIDE

It occurs as a white or yellowish white powder, thick gel, or gelatinous pieces with a mild aromatic odour and bitter taste. forms a clear molten mass on heating. It contains not more than 10% of water. It is very soluble in water, acetone and alcohol slightly soluble in benzene; almost insoluble in ether. The anhydrous form is slightly soluble in ether. The aqueous solution is usually slightly alkaline to litmus and produces excess foam on shaking.

It is incompatible with anionic detergents, such as soa and with nitrates. A white precipitate is formed in a l:300 aqueous solution of benzalkonium chloride when nitrates are present in greater amount than the equivalent of 0.5% ammonium nitrate

Uses

1.     Benzalkonium chloride is a quaternary ammonium disinfectant with properties and uses identical to those of othe cationic surfactants (e.g. cetrimide).

2.     Its O.O2 to 0.1% solutio are used to cleanse skin, mucous membranes and wounds a vaginal douche, as a shampoo in seborrhoeic dermititis and higher dilutions for irrigation of the bladder and urethra.

3.     Cream containing benzalkonium chloride are used in the treatmenti napkin rash.

4.     Its lozenges are used for the treatment of superficia infections of the mouth and throat. Its          O. O.1% solution is used as a preservative for some eye-drops.

5.      Benzalkonium chloride has also been used topically in herpes simplex infections.

Side effects

When taken by mouth, benzalkonium and other quaternal ammonium compounds cause nausea and vomiting; strons solution may cause oesophageal damage and necrosis. Othe side effects are depolarising muscle relaxant properties, nervous system, hypotension, coma and haemolysis.

            At the concentrations used on the skin, solutions benzalkonium and other quaternary compounds            do not general cause irritation, but some patients become hypersensitive to the drug after          repeated application.