Biodegradable nanoparticles for improved kidney bioavailability of rhein: preparation, characterization, plasma, and kidney pharmacokinetics

The aim of this work is to develop biodegradable nanoparticles for improved kidney bioavailability of rhein (RH). RH-loaded nanoparticles were prepared using an emulsification solvent evaporation method and fully characterized by several techniques. Kidney pharmacokinetics was assessed by implanting a microdialysis probe in rat's kidney cortex. Blood samples were simultaneously collected (via femoral artery) for assessing plasma pharmacokinetics. Optimized nanoparticles were small, with a mean particle size of 132.6 +/- 5.95 nm, and homogeneously dispersed. The charge on the particles was nearly zero, the encapsulation efficiency was 62.71 +/- 3.02%, and the drug loading was 1.56 +/- 0.15%. In vitro release of RH from the nanoparticles showed an initial burst release followed by a sustained release. Plasma and kidney pharmacokinetics showed that encapsulation of RH into nanoparticles significantly increased its kidney bioavailability (AUC(kidney)/AUC(plasma) = 0.586 +/- 0.072), clearly indicating that nanoparticles are a promising strategy for kidney drug delivery.