Visualization and characterization of drug carrier transportation and distribution in vivo.

Micro/nano-particle drug delivery systems are being developed for improving therapeutic effects. However, most studies can only evaluate the delivery properties by indirectly measuring the pharmacokinetic changes of the drugs. It had been difficult to directly assay the drug carrier status and distribution in vivo. We described here a method using intravital microscopy to visualize individual drug carriers traveling through blood vessels. The transportation and extravasation process of these particles were monitored. The in vivo distribution patterns were also confirmed by fluorescence microscopy studies of the various tissue samples.