Synthesis and characterization of chitosan hybridized zinc phosphate/hydroxyapatite core shell nanostructure and its potentiality as delivery system of oxaliplatin drug.

An advanced form of zinc phosphate/hydroxyapatite nanorods with a core-shell structure (ZPh/HPANRs) was made and then hybridized with chitosan polymeric chains to make a safe biocomposite (CH@ZPh/HPANRs) that improves the delivery structure of traditional oxaliplatin (OXPN) chemotherapy during the treatment of colorectal cancer cells. The qualifications of CH@ZPh/HPANRs in comparison with ZPh/HPANRs as a carrier for OXPN were followed based on loading, release, and cytotoxicity. CH@ZPh/HPANRs composite exhibits a notably higher OXPN loading capacity (321.75 mg/g) than ZPh/HPANRs (127.2 mg/g). The OXPN encapsulation processes into CH@ZPh/HPANRs display the isotherm behavior of the Langmuir model (R2 = 0.99) and the kinetic assumptions of pseudo-first-order kinetics (R2 > 0.89). The steric studies reflect a strong increment in the quantities of the free sites after the chitosan hybridization steps (Nm = 34.6 mg/g) as compared to pure ZPh/HPANRs (Nm = 18.7 mg/g). Also, the capacity of each site was enhanced to be loaded by 10 OXPN molecules (n = 9.3) in a vertical orientation. The OXPN loading energy into CH@ZPh/HPANRs (<40 KJ/mol) reflects physical loading reactions involving van der Waals forces and hydrogen bonding. The OXPN release profiles of CH@ZPh/HPANRs exhibit slow and controlled properties for about 140 h at pH 7.4 and 80 h at pH 5.5. The release kinetics and diffusion exponent (>0.45) signify non-Fickian transport and a complex erosion/diffusion release mechanism. The free CH@ZPh/HPANRs particles display a considerable cytotoxic effect on the HCT-116 cancer cells (9.53 % cell viability), and their OXPN-loaded product shows a strong cytotoxic effect (1.83 % cell viability).