Insight into the Loading and Release Properties of an Exfoliated Kaolinite/Cellulose Fiber (EXK/CF) Composite as a Carrier for Oxaliplatin Drug: Cytotoxicity and Release Kinetics

Kaolinite layers were exfoliated as single sheets and admixed with cellulose fibers, forming an advanced exfoliated kaolinite/cellulose fiber (EXK/CF) composite, which was characterized as a promising carrier for the oxaliplatin (OL) drug to induce safety as well as the therapeutic effect. The EXK/CF composite exhibited promising loading capacity and achieved an experimental value of 670 mg/g and an expected theoretical value of 704.4 mg/g. The loading behavior of OL using the EXK/CF composite followed the pseudo-first-order kinetic model and the Langmuir equilibrium model, achieving an adsorption energy of 7.7 kJ/mol. This suggested physisorption and homogeneous loading behavior of the OL molecules in a monolayer form. The release profile of OL from EXK/CF continued for about 100 h with maximum release percentages of 86.4 and 95.2% in the phosphate and acetate buffers, respectively. The determined diffusion exponent from the Korsmeyer-Peppas kinetic model suggested non-Fickian transport behavior of the OL molecules and releasing behavior controlled by erosion as well as diffusion mechanisms. Regarding the cytotoxic effect, the EXK/CF composite has a high safety impact on the normal colorectal cells (CCD-18Co) and higher toxic impacts on the colorectal cancer cell (HCT116) than the free oxaliplatin drug.