according to Schaefer et al.'s report, as the MCX particle was larger than 10 μm the penetration through the skin surface could be prevented [15]. Since the average diameter of emulsion droplets in MCX-MS-E measured was about 13.0 μm with a large distribution of 1–100 μm, which is similar to the result reported [16], it is anticipated that penetration through the skin could be prevented, suppressing the harmfulness of the MCX molecules to the underlying tissues.