Evaluation of Nitrosyl Ruthenium Complexes Entrapped in an Oil-In-Water Emulsion as Vasodilator Agents

Abstract

Several attempts have been made toward the production of oxide (NO)- releasing agents based on metallic complexes. However, many of these agents have been shown to undergo hydroxide electrophilic attack, thus generating the corresponding nitro species. Entrapped nitrosyl ruthenium species can be stabilized in an oil-in-water (o/w) emulsion and be further used for local NO delivery. This study describes the transdermal permeation of cis and trans- (RuCl(bpy)2NO)(PF6)2 complexes as NO-donor agents from a topically applied emulsion, with NO release rates of 0.042 ± 0.002 and 0.035 ± 0.003 � mol/cm 2 .h, respectively. In vitro skin permeation studies performed with the cis and trans- (RuCl(bpy)2(NO))(PF6)2 complexes in o/w emulsion showed that they tend to accumulate in the stratum corneum (SC) and viable skin, with spontaneous NO release occurring in the viable skin only. NO release was detected by using an NO- sensor when the complexes were in contact with the sonicated skin. The vascular responses to the NO released from the cis and trans-(RuCl(bpy)2(NO))(PF6)2 complexes in o/w emulsion were also evaluated by vasodilation experiments.