Characterization of β-Cyclodextrin Hybridized Diatomite as Potential Delivery Systems of Oxaliplatin and 5-Fluorouracil Drugs; Equilibrium Modeling of Loading and Release Kinetics

Abstract

The present study involved the functionalization of diatomite’s bio-siliceous frustules with polymeric chains of β-cyclodextrin (β-CD/Di) to serve as advanced delivery structures for the anticancer drugs oxaliplatin (OXPL) and 5-Fluorouracil (5-Fu). The β-CD/Di carrier demonstrated significant loading capabilities, particularly at saturation (324.8 mg/g (OXPL) and 425 mg/g (5-Fu). Both OXPL and 5-Fu were loaded onto the β-CD/Di according to the kinetic properties of the traditional pseudo-first order model (R 2 > 0.90) and the isotherm assumptions of the classic Langmuir model (R 2 = 0.99). The density of occupied active sites on the β-CD/Di was found to be 38.76 mg/g and 88.19 mg/g during the loading process of OXPL and 5-Fu, respectively. The loading energies, which were less than 40 KJ/mol, confirmed the primary and significant influences of the physical mechanisms. The observed release profiles of OXPL and 5-Fu exhibited significant sustained and prolonged characteristics for up to 100 h. The release kinetic modeling and diffusion exponent values (>0.45) verified the release of OXP and 5-Fu based on non-Fickian transport features and the erosion/diffusion process. The β-CD/Di carrier significantly augmented the cytotoxic effects of OXPL and 5-Fu on HCT-116 cancer cell lines (OXPL (9.72% cell viability), and 5-Fu (4.17% cell viability)).