title: Electrically modulated transdermal delivery of fentanyl.
abstract: OBJECTIVE
  Test to determine if iontophoresis and electroporation, alone or in combination, can be used for rapid and modulated delivery of fentanyl.
  
  
  METHODS
  Fentanyl citrate (5 mg/ml) dissolved in pH 4.0 citrate buffer was delivered in vitro across human epidermis. For iontophoresis. a current of 0.5 mA/cm2 was applied for 5 h, using silver/silver chloride electrodes. Electroporation protocol consisted of applying 15 exponential pulses of 500V (applied voltage) and 200 msec duration at the rate of 1 pulse per minute at time zero and, in some cases, repeating at 1.5 and 2.5 h.
  
  
  RESULTS
  There was no measurable permeation of fentanyl through human epidermis under passive conditions. A significant flux (about 80 microg/cm2-hr) was achieved using iontophoresis and decreased once the current was turned off. A 4-fold higher flux and shorter lag time was observed with electroporation as compared to iontophoresis. The flux was found to recover quickly (within 1 h) following pulsing. Modulation of transdermal delivery of fentanyl was demonstrated by both iontophoresis and electroporation.
  
  
  CONCLUSIONS
  Electrically assisted transdermal delivery of fentanyl significantly increased transport compared to passive delivery. Also, rapid and modulated delivery was shown to be feasible by programming the electrical parameters.
authors.affiliation: Dept Pharmaceutical Sciences, School of Pharmacy, Mercer University, Atlanta, Georgia 30341, USA.
authors.forename: Rajkumar
authors.initials: R
authors.lastname: Conjeevaram
authors.forename: Ajay K
authors.initials: AK
authors.lastname: Banga
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
mesh_terms: D000279:Administration, Cutaneous; D016503:Drug Delivery Systems / Q000379:methods* / Q000706:statistics & numerical data; D018274:Electroporation / Q000379:methods* / Q000706:statistics & numerical data; D005283:Fentanyl / Q000008:administration & dosage*; D006801:Humans; D066298:In Vitro Techniques; D012869:Skin Absorption / Q000187:drug effects* / Q000502:physiology
chemical_list: D005283:Fentanyl