“…A review of the available literature for the pertinent data indicates that insulin has been predominantly delivered through the skin using physical methods like iontophoresis (Rao and Misra, 1994, Pillai et al, 2003a, Pillai et al, 2003b, Pillai and Panchagnula, 2003a, Pillai and Panchagnula, 2003b, Pillai et al, 2004a, Pillai et al, 2004b) and sonophoresis (Mitragotri et al, 1996), with very few reported studies on the use of CPEs. Pillai et al and Choi et al (Choi et al, 1999, Pillai and Panchagnula, 2003a, Pillai and Panchagnula, 2003b, Pillai et al, 2004b) have studied the effect of solvents like ethanol, propylene glycol, ethyl acetate and isopropyl myristate on insulin permeation.…”