Insight into the Physiochemical and Cytotoxic Properties of β-cyclodextrin Hybridized Zeoilitic Diatomite as an Enhanced Carrier of Oxaliplatin Drug: Loading, Release, and Equilibrium Studies

The bio-siliceous frustules of diatomite (DA) were zeolitized (ZD) and functionalized with β-cyclodextrin polymeric chains (β-CD/ZD) as enhanced delivery structures of oxaliplatin drug (OXP) as compared to raw diatomite. The encapsulation capacities of ZD (112.5 mg/g) and β-CD/ZD (238.7 mg/g) are significantly higher than the determined capacity of DA (65.9 mg/g). The encapsulation of OXP into β-CD/ZD as well as ZD and DA occurred according to the kinetic properties of the classic pseudo-first-order model (R 2 > 0.92) and the isotherm assumptions of the classic Langmuir model (R 2 = 0.99). The occupied active OXP encapsulation site density of β-CD/ZD is 70.2 mg/g, reflecting enhancement in the quantities of the active sites after the functionalization process as compared to ZD (44.6 mg/g) and DA (28.4 mg/g). Additionally, each encapsulation site on the surface of β-CD/ZD can be occupied with up to 4 OXP molecules by multi-molecular processes and in a vertical orientation. The determined encapsulation energies ( 0.45) validate the release of OXP according to the non-Fickian transport properties and erosion/diffusion mechanism. These structures enhanced notably the cytotoxic effects of OXP on the HCT-116 cancer cell lines as drug carriers ZD (9.76% cell viability) and CF/ZD (6.23% cell viability).