A preliminary study of the in vivo behaviour of an emulsion formulation of indocyanine green

Indocyanine green (ICG;) is a fluorescent dye largely used as functional indicator, fluorescent imaging contrast agent and recently as enhancer during diode laser photocoagulation. In this study, indocyanine green was incorporated in an emulsion to increase its residence time in blood. In vitro results to show that indocyanine green absorption peak is shifted towards longer wavelength (from 778 nm to 794 nm) close to the peak emission wavelength of the near infrared diode laser (805 nm) used during laser-induced photocoagulation. Plasmatic clearance is slower (in the 15-60 min time interval) compared to the plasmatic clearance of ICG administered as an aqueous solution. The absorbing capacity of ICG at 805 nm shows a two- to threefold increase when indocyanine green is incorporated in this emulsion.