Study on synthesis of cross-linked poly(cyclotriphosphazene-co-luteolin) nanospheres and their properties for controlled drug delivery

In this study, cross-linked poly(cyclotriphosphazene- co -luteolin) (PCTPLT) nanospheres were prepared via polymerization-induced self-assembly. The particular band at 945 cm −1 in the Fourier transform infrared (FT-IR) spectra of the nanospheres demonstrated that the polymerization was successful. The morphology of the PCTPLT nanospheres was studied by scanning electron microscope (SEM) and the results revealed that the formation, stable growth, and particle size of the nanospheres strongly depended on the HCCP:LUT mole ratio. The X-ray diffraction (XRD) results showed that the crystalline peaks were completely lost after polymerization. The thermal properties of PCTPLT nanospheres were checked by thermogravimetric analysis (TGA) and the results exhibited that the increase in thermal properties was due to the strong covalently bonded cross-linked structure of the nanospheres. The doxorubicin (DOX) was loaded on the PCTPLT-3 nanospheres and their in vitro release behavior was checked at pH 4.0 and 7.4, and the results showed a cumulative release of 69.7% at pH 4.0 and 48.1% at pH 7.4 after 360 h. Graphical Abstract