Phenylethanol enhancement of preservatives used in ophthalmic preparations

Abstract

The growth rates of P. aeruginosa in subinhibitory concentrations of antibacterial preservatives alone and in combination with phenylethanol were determined by an extinction method. Phenylethanol enhances the effect of benzalkonium chloride on growing cultures of P. aeruginosa and the results have been confirmed by viable counts. A similar effect is shown by phenylethanol in combination with chlorbutol, chlorhexidine diacetate, chlorocresol, merthiolate, methyl and propyl hydroxybenzoate mixture and phenylmercuric nitrate.