Antibacterial lotion testing: a practical approach to demonstrate the antibacterial efficacy of a triclosan-containing leave-on moisturizer

Synopsis Ordinary hand washing is well regarded as the primary means of removing bacteria from the hands. Because typical daily hand washings are not always thorough, antibacterial wash products provide an extra measure of protection by depositing a residual antibacterial agent to the skin that persists after washing. However, a more direct means of delivering antibacterial agents to the skin could be through a leave‐on hand lotion. This paper describes testing which demonstrated that triclosan, a common antibacterial ingredient when administered in an oil‐in‐water anionic emulsion, was substantive to skin and effective against bacteria in both laboratory settings and in the normal daily environment. In vitro and in vivo methods were used to demonstrate the antibacterial lotion’s spectrum of activity, substantivity on skin, persistence of activity, activity vs. resident flora and overall activity in practical use. The work established that a leave‐on lotion was a suitable vehicle for the delivery of an antibacterial active ingredient to skin and that the actives delivered from a leave‐on lotion were effective in use. Although it is recognized that antibacterial lotions are not a substitute for thorough hand washing and good hygienic practices, this work shows that antibacterial lotions can complement washing by providing consumers with a demonstrable reduction in bacterial levels on their skin. Furthermore, the work shows that the methods described could effectively quantify the antibacterial effects of a leave‐on lotion both in the laboratory and in actual use. Résumé Le lavage habituel des mains est considéré comme le premier moyen d’éliminer les bactéries de celles‐ci. Comme les lavages quotidiens des mains ne sont en général pas toujours complets, les produits de lavage antibactériens offrent une mesure supplémentaire de protection par le dépôt d’un agent antibactérien résiduel sur la peau qui perdure après le lavage. Cependant, un moyen plus direct de délivrer des agents antibactériens à la peau pourrait être une lotion pour mains sans rinçage. Cet article décrit les essais qui démontrent que le triclosan, un ingrédient antibactérien courant, lorsqu’il est administré par une émulsion anionique huile‐dans‐eau, est compatible avec la peau et efficace contre les bactéries aussi bien en laboratoire que dans l’environnement quotidien courant. Des méthodes in vivo et in vitro ont été utilisées pour démontrer le spectre d’activité de la lotion antibactérienn