Exploiting fluorescein based drug conjugates for fluorescent monitoring in drug delivery

Anticancer drugs connected to fluorescein based chemosensors by different biodegradable linkers were investigated for fluorescent monitoring in drug delivery models. The drug release triggered by chemo- and bio-hydrolytic environments was visualized on the basis of “switch on” fluorescence of the fluorophore moiety of fluorescein-drug conjugates. The conjugation of free phenolic hydroxyl of fluorescein chemosensor to the hydroxyl group of the drugs was employed by biodegradable oxy- and amino acrylate linkers. The chemosensor also possesses a free carboxylic group for potential conjugation to a specific carrier for targeted drug delivery applications. Fluorescent monitoring of drug release, quantum yield and other spectroscopic characteristics of our novel fluorescein-drug conjugates were measured and discussed. The work offers a versatile fluorophore platform for the fluorescent observation of drug delivery.