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 eigh