Delivery of an Antimicrobial Agent From Topical Drug Delivery Systems

Abstract

This research was focussed on improving and optimising the topical delivery of a specific antimicrobial from various drug delivery systems. The drug of interest was triclosan. The main objective of this study was to deliver this drug to the lower layers of the skin over an extended period of time during catheter use. To attain continuous release of triclosan, topical drug-in-glue adhesives were formulated and tested. Permeation enhancers were incorporated into the adhesives to improve the permeation rates of triclosan across human epidermal skin. Permeation studies demonstrated that the inclusion of the enhancer oleic acid improved the permeability of triclosan over the other enhancers used. This finding was attributed to the mechanism of action of oleic acid, which is responsible for disrupting the lipid lamellae of the stratum corneum, thereby improving the triclosan permeation. In order to improve the drug-in-adhesive formulation further, a novel patch system was developed, where instead of a backing liner, a silicone elastomer layer containing triclosan was utilised as part of the adhesive to generate further sustained release of triclosan. Investigations were undertaken to observe the release of triclosan from the silicone elastomer material which also contained different additives. It was found that linoleic acid was a suitable additive within the silicone matrix. Comparative studies were carried out to reveal which of the silicone/adhesive drug delivery systems provided the greatest permeation rate. The drug delivery system composed of linoleic acid in the silicone layer and oleic acid in the adhesive layer provided the greatest permeation rate of triclosan over 14 days compared with any other system tested within these studies, and reached concentrations higher than the necessary minimum inhibitory concentration and minimum bactericidal concentration values, suggesting this patch type system could potentially be used for disinfecting the skin during catheter use.