Preservatives in Topical Ophthalmic Medications: Historical and Clinical Perspectives

P. David Freeman; Malik Y. Kahook


Expert Rev Ophthalmol. 2009;4(1):59-64. 

In This Article

Classification of Preservatives

Historically, preservatives have been classified into two categories: detergent and oxidizing preservatives. More recently, a newer system of preservation, ionic-buffered preservatives (acting as oxidizing preservatives), has been introduced; their methods of action and examples of each different type are described later.

Detergent Preservatives

Detergents are compounds that cause bacterial cell death by way of interrupting the lipid component of cell membranes. The contents of the microbial cell are extruded from the cell due to membrane instability. As described earlier, detergents have the longest running history in ophthalmic medicine. Examples of detergent-type preservatives include benzalkonium chloride (BAK) and cetrimonium.[3]