Manipulation of pH-Sensitive interactions between podophyllotoxin-chitosan for enhanced controlled drug release

Podophyllotoxin (PPT) offers a broad-spectrum of anticancer activities, but little has been reported for its controlled release. This work shows that by manipulating molecular interactions between PPT and Chitosan, efficient nanoscale capsulation of PPT can be realized. The drug encapsulation efficiency is as high as 52%, with a final particle drug loading in the order of 10% (wt/wt). It further demonstrates that changes in pH can also significantly affect the rate of drug release from the Chitosan nanoparticles. Upon contact with cancer cells, chitosan nanoparticles enable efficient internalization and drug release. In vitro evaluations with HepG-2 and MCF-7 cells indicate that the chitosan nanoparticle carriers can improve drug efficacy in comparison to free PPT, most likely by regulating the intrinsic apoptotic signaling pathway to induce apoptosis. Overall, PPT chitosan nanoparticles promise a safe and efficient drug delivery system for PPT.