title: Iontophoresis successfully delivers dexamethasone sodium phosphate to dermis as measured by microdialysis.
abstract: Despite its widespread and long term use, the effectiveness of iontophoresis to increase the delivery of dexamethasone sodium phosphate (DSP) remains controversial. The goal of this study was to quantitatively compare the DSP concentrations in dermis' dialysates in two delivery scenarios: with and without iontophoresis. Interstitial fluid concentrations were measured by cutaneous microdialysis. Passive and active iontophoresis were applied simultaneously on the skin of the forearm in eight healthy adult participants using each participant as his/her own control. The iontophoresis apparatus and procedures were identical to those used in common clinical practice. Iontophoresis electrodes were loaded with 2 mL of 4.4 mg/mL of preservative-free DSP solution. Electric current (4 mA) was applied for 20 min. Dialysate samples were collected for 2 h and analyzed for DSP and its active metabolite dexamethasone (DXM). Seven out of eight iontophoresis sites contained quantifiable levels of DSP and DXM, whereas none of the samples collected at the passive site contained either form of the drug. In conclusion, this study demonstrates that iontophoresis significantly (p < 0.0001) increases delivery of DSP to the dermis compared with passive delivery of the same, and that microdialysis can be used to monitor DSP delivery and DXM formation in skin.
authors: Division of Pharmaceutical Sciences, Arnold and Marie Schwartz College of Pharmacy, Long Island University, Brooklyn, New York, 11201.
authors: Abhay
authors: A
authors: Joshi
authors: Grazia
authors: G
authors: Stagni
authors: Ann
authors: A
authors: Cleary
authors: Komal
authors: K
authors: Patel
authors: David S
authors: DS
authors: Weiss
authors: Marshall
authors: M
authors: Hagins
mesh_terms: D000328:Adult; D000818:Animals; D020405:Dermis / Q000378:metabolism*; D003907:Dexamethasone / Q000008:administration & dosage / Q000031:analogs & derivatives*; D016503:Drug Delivery Systems / Q000379:methods; D005260:Female; D006801:Humans; D007478:Iontophoresis / Q000379:methods; D008297:Male; D017551:Microdialysis / Q000379:methods; D011817:Rabbits; D055815:Young Adult
chemical_list: C004180:dexamethasone 21-phosphate; D003907:Dexamethasone
keywords: bioavailability; iontophoresis; microdialysis; passive diffusion/transport; percutaneous; skin; transdermal drug delivery