3. Antiseptics that have been used to treat CSOM.

Antiseptic agent used aurally	Target and mechanism of action
Rubbing alcohol (ethanol, isopropanol)	Penetrating agents that cause loss of cellular membrane function, leading to release of intracellular components, denaturing of proteins, and inhibition of DNA, RNA, protein and peptidoglycan synthesis.
Povidone‐iodine	Highly active oxidising agents that destroy cellular activity of proteins. Disrupts oxidative phosphorylation and membrane‐associated activities. Iodine reacts with cysteine and methionine thiol groups, nucleotides and fatty acids, resulting in cell death.
Chlorhexidine	Membrane‐active agents that damage cell wall and outer membrane, resulting in collapse of membrane potential and intracellular leakage. Enhanced passive diffusion mediates further uptake, causing coagulation of cytosol.
Hydrogen peroxide	Produces hydroxyl free radicals that function as oxidants, which react with lipids, proteins and DNA. Sulfhydryl groups and double bonds are targeted in particular, thus increasing cell permeability.
Boric acid	It is likely that the change in the pH media of the ear canal interrupts the growth of bacteria by affecting the amino acid, which causes alteration in the three‐dimensional structure of bacterial enzymes. Extreme changes in pH cause protein denaturation.
Aluminium acetate/acetic acid	Acetic acid changes the pH media of the ear canal and interrupts the growth of bacteria by affecting the amino acid, which causes alteration in the three‐dimensional structure of bacterial enzymes. Extreme changes in pH cause protein denaturation. Aluminium acetate is an astringent that helps reduce itching, stinging and inflammation.

Sources: Gupta 2015; McDonnell 1999; Sheldon 2005.