Drug delivery platform comprising long-wavelength fluorogenic phenolo-cyanine dye for real-time monitoring of drug release

Drug delivery platforms comprising an anticancer drug bound to a fluorogenic dye are of great importance for theranostics and personalized medicine. The existing platforms suffer from insufficient water-solubility and, in addition, their emission lies in the short-wavelength spectral region, which is not suitable for probing in the body. Herein, water-soluble, fluorogenic phenolo-cyanine dyes were synthesized and bound to the anti-cancer drug chlorambucil by means of a biodegradable ester linker to form a novel NIR fluorescent, anticancer drug delivery platform. This platform exhibits no detectable fluorescence, but upon environment-mediated drug release brightly emits at 720 nm. The obtained platform contains reactive carboxylic functionality facilitating its labeling to a cancer-targeting carrier such as a peptide, antibody or nanoparticle and is therefore promising for cancer treatment applications.