APPLICATIONS OF IN VIVO EPR SPECTROSCOPY AND IMAGING TO SKIN

Electron paramagnetic resonance (EPR) spectroscopy and imaging of free radicals in human skin performed at low-frequency (3 GHz) continuous-wave EPR is a promising technique to study redox metabolism, formation of free radicals and reactive oxygen species, oxygen concentration, barrier function and drug penetration in vivo. The method relies on the application of nitroxides, nitroxide labeled drugs or nitrone spin traps. Pyrrolidine and piperidine type nitroxides have a low potential to cause dermatotoxic effects such as irritant or allergic contact dermatitis and can possibly be used safely for topical in vivo studies. Dermatologic applications of the EPR technique are discussed including in vitro studies, which show the potential for in vivo investigations.