the permeation rate depended on droplet size. The emulsion with the lowest droplet size(54 nm) achieved the maximum permeation rate.
The concentration of D-limonene in the skin was 40.11 lL/cm2 at the end of 360 min.
Histopathology revealed no distinct voids or empty spaces in the epidermal region of permeated rat skin, so the D-limonene nanoemulsion may be a safe carrier for transdermal drug delivery.