Abstract
Clinoptilolite as a natural zeolite was integrated with green CaO nanoparticles forming the green nanocomposite CaO(NP)/Clino. The CaO(NP)/Clino composite was assessed as a potential carrier for 5-fluorouracil (5-FL) drug. The CaO(NP)/Clino carrier achieved an enhanced 5-FL loading capacity of 305.3 mg/g as compared to 163 mg/g for pure clinoptilolite. The kinetics of the 5-FL loading follow the properties of the pseudo-first-order model, while the equilibrium results are related to the Langmuir isotherm. Therefore, the 5-FL loading processes occurred in the monolayer formed by homogeneous active loading receptors on the surface of the CaO(NP)/Clino carrier. The Gaussian energy of the 5-FL loading reaction (9.2 KJ/mol) reflected the dominant effect for the chemical mechanisms, especially the zeolitic ion-exchange mechanisms. Additionally, the thermodynamic parameters suggested endothermic, feasible, and spontaneous properties for the occurred 5-FL loading reactions. The release profile of 5-FL from CaO(NP)/Clino has continuous and long properties (150 h) at pH 1.2 (gastric fluid) and pH 7.4 (intestinal fluid). The kinetic studies of the release reactions show considerable agreement with Higuchi, Hixson-Crowell, and Korsmeyer-Peppas models. Such high fitting results and the diffusion exponent values (0.49 at pH 1.2 and 0.48 at pH 7.4) reflected the release properties of the Fickian transport behavior involving complex erosion and diffusion mechanisms. The cytotoxicity study of CaO(NP)/Clino on colorectal normal cells (CCD-18Co) declare the safe and biocompatible effect as a carrier for the 5-FL drug. Additionally, CaO(NP)/Clino as a carrier causes considerable enhancement for the cytotoxic effect of the loaded 5-FL drug on colon cancer cells (HCT-116).