Hyaluronic acid and polyethylenimine self-assembled polyion complexes as pH-sensitive drug carrier for cancer therapy

•The PICs had negatively charged surface and were stable in physiological milieu.•The PICs could load small molecules and induce targeted drug delivery.•The PICs could behave pH responsive drug release behavior. In this study, a series of polyion complexes (PICs) were prepared via electrostatic interaction between hyaluronic acid–histidine conjugate (HH) and polyethylenimine–histidine conjugate (PH). These PICs with the average size ranging from 410.5nm to 98.5nm at different weight ratios of HH/PH were able to encapsulate doxorubicin (DOX) as the model antitumor drug. The PICs at the weight ratio of 4:1 had negative surface charge and were of good dispersity and stability in the solution containing serum. In vitro drug release assay demonstrated that the DOX release rate were higher at acidic pH showing a controllable property. These HA coated PICs could targetedly deliver DOX to B16F10 tumor cells, showing improved antitumor activity.