The present invention refers to a pharmaceutical formulation for injection comprising fluorescent nanoparticles as in vivo diagnostics. The present invention relates to an injectable pharmaceutical formulation for human medicine and/or veterinary use, comprising 17% to 20% per weight of poloxamer 407 and 3% - 15% per weight of poloxamer 188, 0.10 nM to 10.0 μΜ fluorescent nanoparticles and water or an aqueous buffer, wherein the pharmaceutical formulation is liquid at 4°C - 32°C and forms a gel at about 37°C, their use as an