Assessment of Skin Erythema After Exposure to Different Doses of Methyl Nicotinate
ARMY RESEARCH INST OF ENVIRONMENTAL MEDICINE NATICK MA
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The purpose of this study was to determine the topical dose of methyl nicotinate Mnic that optimized skin blood flow for a 30-minute period. Methyl nicotinate is a topical vasodilator used to evaluate the integrity of skin protection compounds. Specifically, this test dose of Mnic was used to evaluate the ability of SERPACWA Skin Exposure Reduction Paste Against Chemical Warfare Agents, a recently FDA approved topical skin protectant, to provide an efficacious barrier to this challenge agent. Six subjects were studied in a climate-controlled room 22-24 deg C, 25-30 rh. Three application sites were marked on the volar surface of each forearm 2.4-cm diameter. A 10 ml sample of each of six aqueous Mnic concentrations 0, 1.25, 2.5, 5, 10, or 25 mMol was applied to the volar surface of each forearm and removed after two minutes. Laser Doppler Imaging LDI was used to measure basal skin blood flow and cutaneous erythema following application of Mnic to each site. The LDI scans were performed prior to Mnic application baseline and were repeated approximately every 3 minutes for approximately 30 minutes post Mnic exposure. Statistically, cutaneous erythema was significantly greater with 2.5, 5, 10, and 25 mMol doses compared to 0 and 1.25 mMol doses p 0.05. Cutaneous erythema was also greater with 5 mMo1 than with 2.5 mMo1 p 0.05. There were no significant differences among the 5, 10 and 25 mMo1 doses. Cutaneous erythema was greater than baseline at 9 minutes post Mnic exposure p 0.05 and peaked at 12 minutes post Mnic exposure. Cutaneous erythema was not different between 12 and 25 minutes post Mnic exposure, but was significantly attenuated at 28 minutes compared to 12 minutes post Mnic exposure value p 0.05. These results indicate that 5 mMo1 Mnic induces optimal cutaneous erythema between 12 and 25 minutes post Mnic challenge and that increasing the Mnic dose does not further increase cutaneous erythema.
- Chemical, Biological and Radiological Warfare