P-2 Switchable Phenolo-cyanine Reporters for Fluorescence-based Targeted Drug Delivery Monitoring

The fluorescence based sensing of drugs transported to specific biological targets has emerged as an important research topic in the field of drug delivery monitoring. In this work, bifunctional, on-off switchable fluorescein reporter FLU-CH2-CO2H was synthesized and bound to anticancer drugs — chlorambucil (CLB), tubulizine (TBZ), curcumin (CMN), and amonafide (AM) by means of different biodegradable linkers (L). The drug release triggered by bio-hydrolytic environment was fluorescently monitored and the obtained cleavage profiles were found to be in good agreement with those measured by spectrophotometric and LC/MS methods. The cleavage rates are strongly dependent on the linker nature. The half-lives vary in a wide range between 20 sec and 14 h. Calibration curves for the fluorescence signal versus the released drug concentrations were obtained.