This work explores the possibility of achieving therapeutic levels of the anti-Parkinsonian drug, ropinirole hydrochloride (RHCl), by transdermal iontophoretic delivery. An in vivo study was performed in hairless rats during which RH(+) was delivered at one current intensity (0.58 mA identical with 0.12 mA/cm(2)) and at three different drug concentrations (25, 125, and 250 mM). In vivo RH(+) flux and transport number were deduced from the steady-state plasma concentration values. Plasma concentration profiles and RH(+) transport numbers were independent of the drug donor concentration. The average iontophoretic input rate was about 3 micromol/h. Postiontophoresis transepidermal water loss (TEWL) was monitored and biopsies were histologically examined to identify any effects of iontophoresis on the skin. TEWL was elevated only at the anodal sites. TEWL recovery was faster for the "no-drug" control anodal sites, which suggests a combined effect of the drug and current on the skin. In conclusion, (1). the in vivo iontophoretic transport of RH(+) is independent of the drug donor concentration, and (2). iontophoresis can deliver therapeutic amounts of RH(+).
Copyright 2003 Wiley-Liss, Inc.