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

Indocyanine green (ICG;) is a fluorescent dye largely used as functional in dicator, fluorescent imaging contrast agent and recently as enhancer during diode laser photocoagulation. In this study, indocyanine green was incorpo rated in an emulsion to increase its residence time in blood. In vitro resu lts to show that indocyanine green absorption peak is shifted towards longe r 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 photoco agulation. Plasmatic clearance is slower (in the 15-60 min time interval) c ompared to the plasmatic clearance of ICG administered as an aqueous soluti on. The absorbing capacity of ICG at 805 nm shows a two- to threefold incre ase when indocyanine green is incorporated in this emulsion.