Controlled topical delivery of nitric oxide for treating infected cutaneous wounds

Topical delivery of nitric oxide (NO) can potentially be used to accelerate healing of acute and chronic wounds while inhibiting wound infections. The purpose of this study was to develop a method for delivering NO to a wound bed in a controlled manner, characterize its release rate and antimicrobial activity, and evaluate mammalian cytotoxicity. NO-bound zeolite particles were combined with emulsifying ointment and subsequently encapsulated into polymer membranes with varied permeabilities. Release properties of these pouches were quantified using a Sievers 280i Nitric Oxide Analyzer with a chemiluminescence detection system. Antimicrobial efficacy was tested on methicillin resistant Staphylococcus aureus (MRSA), while cytotoxicity was tested on 3T3 fibroblasts. The release rate of NO was found to be positively correlated with the rate of moisture entry into the pouch. Compared with controls, the pouch with the fastest nitric oxide release rate resulted in a 6-log reduction in MRSA colonies, while the others inhibited growth to a lesser extent. Moreover, the fast release pouch reduced fibroblast viability by approximately 50%. These data suggest that NO pouches can be incorporated into wound dressings for antimicrobial treatment.