pH-sensitive β-cyclodextrin derivatives for the controlled release of Podophyllotoxin

•Inclusion complexes of podophyllotoxin with two pH-sensitive β-cyclodextrin derivatives were designed and prepared.•Inclusion complexes were characterized by NMR, XRD, DSC and SEM analysis.•Water solubility of PPT are significantly increased by 502.92 and 190.75 folds after formation of inclusion complexes.•Two pH-sensitive β-cyclodextrin derivatives acid-controlled release has been studied via 1H NMR and UV-Vis spectra.•CCK assays shows their biosafety to normal cell as well as significantly enhanced anti-tumor activity.