Fluorescent nanoparticles of chitosan complex for real-time monitoring drug release.

New types of fluorescent nanoparticles (FNPs) were prepared through ionic self-assembly of anthracene derivative and chitosan for applications as drug delivery carriers with real-time monitoring of the process of drug release. Because of the presence of the hydrophilic groups, these FNPs showed excellent dispersion and stability in aqueous solution. The structure and properties of the FNPs were investigated by using means of (1)H NMR, FTIR, SEM, dynamic light scattering (DLS), and so on. The potential practical applications as drug delivery carriers for real-time detection of the drug release process were demonstrated using Nicardipine as a model drug. Upon loading the drug, the strong blue fluorescence of FNPs was quenched due to electron transfer and fluorescence resonance energy transfer (FRET). With release of drug in vitro, the fluorescence was recovered again. The relationship between the accumulative drug release of FNPs and the recovered fluorescence intensity has been established. Such FNPs may open up new perspectives for designing a new class of detection system for monitoring drug release.