Potentiality of zinc phosphate@hydroxyapatite/β-cyclodextrin composites for carrying cisplatin: loading, release and cytotoxicity

Abstract

A zinc phosphate/hydroxyapatite composite (ZP/HAP) with a core–shell nano-rod morphology and its functionalized derivative with β-cyclodextrin (β-CD) were evaluated as potential carriers of the drug cisplatin (CPN). The developed CD@ZP/HAP displayed remarkably enhanced CPN loading properties (375.8 mg g⁻¹) compared to ZP/HAP (259.8 mg g⁻¹). The CPN loading behavior of CD@ZP/HAP followed Langmuir isotherm properties (R² > 0.99) and the kinetic activities of the pseudo-first-order model (R² > 0.97). The steric assessment validated the notable increase in existing loading receptors after the functionalization of ZP/HAP with β-CD from 57.7 mg g⁻¹ (ZP/HAP) to 72.3 mg g⁻¹. Functionalization also affected the capacity of each receptor, ensuring that there were six CPN molecules (CD@ZP/HAP) instead of five (ZP/HAP), as well as the loading energies (<40 kJ mol⁻¹), the loading of CPN by physical multi-molecular processes, and the vertical orientation. The CPN release patterns of CD@ZP/HAP exhibited slow and controlled properties (94.5% after 200 h at pH 7.4, and 100% after 160 h at pH 5.5), which were faster than those of ZP/HAP. The kinetic modeling of the release activities and diffusion exponent (>0.45) reflected the release of CPN according to both erosion and diffusion mechanisms. The loading of CPN into both ZP/HAP and CD@ZP/HAP also resulted in a marked enhancement in the anticancer activity of CPN against human cervical epithelial malignancies (HeLa) (cell viability = 5.6% (CPN), 3.7% (CPN loaded ZP/HA), and 1.8% (CPN loaded CD@ZP/HAP)).