title: Iontophoresis-facilitated delivery of prednisolone through throat skin to the trachea after topical application of its succinate salt.
abstract: OBJECTIVE
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Faculty of Pharmaceutical Sciences, Josai University, 1-1 Keyakidai, Sakado, Saitama, 350-0295, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ishii
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Suzuki
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Todo
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Kamimura
authors.forename: Kenji
authors.initials: K
authors.lastname: Sugibayashi
mesh_terms: D000287:Administration, Topical; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics; D016503:Drug Delivery Systems / Q000379:methods; D019793:Fluorescein / Q000008:administration & dosage / Q000493:pharmacokinetics; D066298:In Vitro Techniques; D007478:Iontophoresis; D008297:Male; D015394:Molecular Structure; D010614:Pharynx / Q000378:metabolism*; D011241:Prednisone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D051381:Rats; D054772:Rats, Hairless; D012867:Skin / Q000378:metabolism*; D012869:Skin Absorption; D014132:Trachea / Q000378:metabolism*
chemical_list: D000893:Anti-Inflammatory Agents; C046348:prednisone sodium succinate; D019793:Fluorescein; D011241:Prednisone