Rapid radial transport of methyl nicotinate in the dermis.

Topical application of a sufficiently concentrated aqueous solution of methyl nicotinate elicits within minutes an erythematous, vasodilatory response in humans. In this study the radial increase of the erythematous area visible in the skin has been followed as a function of solution application time and methyl nicotinate concentration. Because of the nature of the physiological response, the observations are interpreted in terms of the dermal movement of the drug. The rate of radial spread was much more rapid than can be accounted for in terms of simple diffusion, and a mechanism involving transport by the blood flowing in the dermal vasculature is proposed.