Burn wound progression is an
inflammation-driven process where an initial partial-thickness thermal
burn wound can evolve over time to a full-thickness injury. We have developed an oil-in-water nanoemulsion formulation (NB-201) containing
benzalkonium chloride for use in
burn wounds that is antimicrobial and potentially inhibits
burn wound progression. We used a porcine
burn injury model to evaluate the effect of topical nanoemulsion treatment on
burn wound conversion and healing. Anesthetized swine received thermal
burn wounds using a 25-cm2 surface area
copper bar heated to 80°C. Three different concentrations of NB-201 (10, 20, or 40% nanoemulsion),
silver sulfadiazine cream, or saline were applied to burned skin immediately after injury and on days 1, 2, 4, 7, 10, 14, and 18 postinjury. Digital images and skin biopsies were taken at each dressing change. Skin biopsy samples were stained for histological evaluation and graded. Skin tissue samples were also assayed for
mediators of inflammation. Dermal treatment with NB-201 diminished thermal
burn wound conversion to a full-thickness injury as determined by both histological and visual evaluation. Comparison of epithelial restoration on day 21 showed that 77.8% of the nanoemulsion-treated
wounds had an epidermal injury score of 0 compared to 16.7% of the
silver sulfadiazine-treated
burns (P = .01).
Silver sulfadiazine cream- and saline-treated
wounds (controls) converted to full-thickness
burns by day 4. Histological evaluation revealed reduced
inflammation and evidence of skin injury in NB-201-treated sites compared to control
wounds. The nanoemulsion-treated
wounds often healed with complete regrowth of epithelium and no loss of hair follicles (NB-201: 4.8 ± 2.1, saline: 0 ± 0,
silver sulfadiazine: 0 ± 0 hair follicles per 4-mm biopsy section, P < .05). Production of inflammatory mediators and sequestration of neutrophils were also inhibited by NB-201. Topically applied NB-201 prevented the progression of a partial-thickness
burn wound to full-thickness injury and was associated with a concurrent decrease in dermal
inflammation.