Protective effect of topical iodine containing anti-inflammatory drugs against sulfur mustard-induced skin lesions

Previous studies have shown the antidotal efficacy of topical iodine at 15 and 30 min post-exposure to sulfur mustard (SM). Here we demonstrate efficacy at longer intervals (20, 30, 45, and 60 min, respectively, for data) using an improved topical povidone-iodine preparation termed N66, which contains steroidal and nonsteroidal anti-inflammatory agents. In the mouse, N66 reduced severity of ear edema by 43, 47, 44, and 36%; ear epidermal ulceration by 74, 58, 45, and 58%; and epidermal necrosis by 54, 34, 26, and 31% at the respective time points. A similar effect was observed with encrustation. The healing marker, grade of acanthotic area, showed dramatic increases of 39.6-, 25.3-, 20.9-, and 22-fold. Severity of the dermal parameters, acute inflammation and dermal necrosis, was reduced by 63, 34, 34, and 38% and 80, 54, 54, and 59%, respectively. In guinea pig skin, topical treatment with N66 45 min post-exposure reduced the SM-induced ulceration area by 75%. The histological parameters subepidermal microblister formation, epidermal ulceration, epidermal necrosis, and encrustation were reduced by 63, 61, 41, and 41%, respectively. The healing marker, grade of acanthotic area, was elevated by 73%. N66 induced a statistically significant reduction in two dermal markers for tissue damage: acute inflammation (33%) and dermal necrosis (48%). Reduced skin damage was also observed in areas adjacent the treated sites. The pharmacologically active components of N66 showed additive effect. These findings suggest that the povidone-iodine preparation combined with antiinflammatory agents functions as a potent antidote against skin lesions induced by SM at relatively long intervals between exposure and treatment.