Author(s): Ishii H , Suzuki T, Todo H, Kamimura M, Sugibayashi K
PURPOSE: The possibility of direct delivery of steroids through the skin to the trachea and the effect of iontophoresis on delivery efficacy were evaluated after the application of an ionic steroidal prodrug, prednisolone sodium succinate (PS-Na), to the throat skin.
METHODS: Fluorescein sodium salt (FL-Na) and PS-Na were applied as model compounds at a concentration of 1% in pH 7.4 phosphate-buffered saline to the throat skin of hairless rats, and constant current-cathodal iontophoresis (0.4 mA/cm(2)) was performed for 8 or 10 h.
RESULTS: In vitro permeation experiment involving cathodal iontophoresis through excised hairless rat abdominal skin revealed 30- and 10-times higher levels of skin permeation of PS and its active drug, prednisolone (P), than those induced without iontophoresis. In vivo iontophoresis treatment of the rat's throat skin produced 2.6-, 1.6- and 12-times higher FL, PS and P concentrations, respectively, in the trachea than those observed without iontophoresis.
CONCLUSION: The present results suggest the usefulness of topical application of the ionic steroidal prodrugs onto throat skin followed by iontophoresis treatment for directly delivering the steroid to the trachea.Journal of Allergy & Therapy