Antimicrobial silicone skin adhesives facilitated by controlled octenidine release from glycerol compartments

Abstract

ABSTRACT For improved wound healing, antimicrobial adhesives are one path forward. However, with the current challenge of bacterial resistance, it is essential to choose the included drug carefully. Octenidine is an obvious choice due to its broad antimicrobial efficacy and no reported bacterial resistance. In its pure form, octenidine complexes efficiently with the platinum catalyst in the silicone composition, inhibiting the targeted hydrosilylation reaction and hindering curing. This obstacle is overcome by screening octenidine with cyclodextrins in homogeneously dispersed glycerol droplets, suppressing Pt inhibition in the silicone phase. Curing efficiency is demonstrated using rheology, which shows that it is possible to incorporate one wt% of octenidine into glycerol–silicone adhesives in the presence of (2-hydroxypropyl)-β-cyclodextrin without affecting the adhesives’ mechanical properties. The interaction between octenidine and (2-hydroxypropyl)-β-cyclodextrin through an inclusion complex is confirmed by ROESY spectroscopy. Despite this screening, octenidine is still released efficiently from the glycerol–silicone adhesives upon contact with water, and the resulting antimicrobial action is subsequently demonstrated. This new technology constitutes a simple and efficient method for preparing wound care adhesives that actively inhibit the growth of four bacteria strains and one fungus. GRAPHICAL ABSTRACT