Polyvinyl pyrrolidone/starch/hydroxyapatite nanocomposite: A promising approach for controlled release of doxorubicin in cancer therapy

Doxorubicin (DOX) is an effective and widely used cancer chemotherapy drug, though its use is extremely dangerous due to side effects such as cardiotoxicity resulting from high doses. Herein, a sustainable and biocompatible starch/polyvinyl pyrrolidone/hydroxyapatite nanocomposite was prepared and loaded with DOX by water-in-oil-in water (W/O/W) emulsification method. Fourier-transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) confirmed the successful synthesis of the nanocomposite and indicated strong interactions between its components. Scanning electron microscopy (SEM) images revealed the quasi-spherical shape of the nanocomposite and dynamic light scattering (DLS) showed an average particle size of 258 nm. The zeta potential at pH 5.4 was −37.28 mV, corroborating its colloidal stability. Doxorubicin release in the ex vivo environment was investigated at pH 5.4 and 7.4, mimicking tumour and physiological conditions, respectively, and the results showed no initial burst release and a faster release kinetics in the acidic environment owed to the repulsive forces among protonated oxygenated groups of the drug and the polymers. The W/O/W improved entrapment efficiency and enabled a gradual DOX release, thus increasing the drug stability. The cell biocompatibility and anticancer activity of the drug-loaded nanocomposite were proved by MTT analysis on breast cancer fibroblast cells (7-MCF). The synthesized nanocomposite shows great potential as an effective nanocarrier of anticancer drugs for controlled release in the acidic environment of the tumour.