Abstract

THE ANTIBACTERIAL EFFECT OF SURFACTANTS IN COMBINATION WITH A COMMONLY USED PHARMACEUTICAL PRESERVATIVE AGAINST BACTERIAL CONTAMINANTS

Hanson Ige Ogbu* and Kingsley Chidimma Ejizu

Abstract

The ability of the microbial contaminant to cause undesirable changes on the pharmaceutical product has prompted the search for suitable antimicrobial agents. Such agent must be able to cope with the contaminants encountered during manufacture, storage and use of the products. It is therefore important that the efficacy of these agents and their spectra of activity be established before their use. In this study, the effect of two surfactants (cetrimide or sodium lauryl sulphate) on the activities of a commonly used pharmaceutical preservative (methylparaben) against bacteria contaminants were evaluated. Forty brands of used topical creams were selected for the isolation of microbial contaminant and subjected to antimicrobial susceptibility testing. This involves the determination of the minimum inhibitory and bactericidal concentration as well as the evaluation of combined effects of preservative and surfactants using continuous variation checkerboard method. Results showed that both surfactants and preservative had antimicrobial effects. Amongst all three agents, cetrimide exhibited the most bactericidal activity against the 4 isolates tested. The combined effect of methylparaben and two surfactants showed that majority of the combination exhibited synergism, a few showed additivity, and none demonstrated antagonism against test organisms. This result highlights the role of surfactants in increasing the antimicrobial activity of the preservative. This would probably be due to the inherent ability of some surfactants, to sensitize the bacteria cells and increase their permeability to the actions of the antimicrobial agents. The study would therefore be useful in selection and optimization of tolerable dosage for pharmaceutical preparations.

Keywords: Antibacterial, Surfactants, Pharmaceutical, Methylparaben, Checkerboard, Creams.