1: Eur J Pharm Biopharm. 2008 Aug;69(3):1077-82. Epub 2008 Feb 20. Non-invasive diagnosis and monitoring of chronic kidney disease by reverse iontophoresis of urea in vivo. Wascotte V, Rozet E, Salvaterra A, Hubert P, Jadoul M, Guy RH, Préat V. Université Catholique de Louvain, Unité de Pharmacie Galénique, Brussels, Belgium. BACKGROUND: Reverse iontophoresis uses a small current to extract molecules and ions through the skin. The aim of the study was to determine whether reverse iontophoresis of urea can be used (i) to diagnose and monitor non-invasively chronic kidney disease (CKD), and (ii) to track urea levels closely during a hemodialysis session. METHODS: A current of 0.8mA was applied for 2h in 10 healthy volunteers, in 9 patients with CKD, and in 10 patients undergoing hemodialysis. Urea fluxes extracted by reverse iontophoresis and urea concentrations in the blood were measured. RESULTS: Extracted urea fluxes discriminated healthy volunteers from patients with CKD within 90 min. A non-invasive measure of blood urea concentrations can be achieved after 120 min. A urea reservoir in the skin interferes with the extraction and a pre-hemodialysis "depletion" period is required. Mild and transient sensation and erythema induced by iontophoresis were significantly lower in the CKD group. Gelling the formulation of the iontophoresis reservoir gave similar results to those obtained when using a simple aqueous solution. CONCLUSIONS: Reverse iontophoresis can be used to non-invasively diagnose individuals with CKD and to monitor urea concentrations in blood. PMID: 18406585 [PubMed - indexed for MEDLINE] Related Links Monitoring of urea and potassium by reverse iontophoresis in vitro. [Pharm Res. 2007] PMID:17380270 Assessment of the "skin reservoir" of urea by confocal Raman microspectroscopy and reverse iontophoresis in vivo. [Pharm Res. 2007] PMID:17497081 Reverse iontophoresis: a non-invasive technique for measuring blood urea level. [Pediatr Nephrol. 2003] PMID:12898373 Influence of the ionic dialysance monitor on Kt measurement in hemodialysis. [Am J Kidney Dis. 2008] PMID:18455852 Simultaneous extraction of urea and glucose by reverse iontophoresis in vivo. [Pharm Res. 2004] PMID:15553226