Use of Zeolite ZSM‐5 for Loading and Release of 5‐Fluorouracil

Samples of zeolite ZSM‐5 have been synthesized in both the sodium form (ZSM‐5) and the acid activated form (H‐ZSM‐5). In addition, each of these two forms was prepared in the two molar SiO 2 /Al 2 O 3 ratios of 169 and 15. All samples of these ZSM‐5 derivatives were characterized by X‐ray diffraction (XRD), nitrogen adsorption‐desorption isotherms, thermal gravimetric analysis (TGA), X‐ray fluorescence (XRF), and scanning electron microscopy (SEM). The samples were successfully loaded with the anticancer drug 5‐fluorouracil (5‐FU) with loading capacities varying from 22% (for the sodium form having the lower molar SiO 2 /Al 2 O 3 ratio of 15, ZSM‐5‐(15)) to 43% (for the corresponding acid form, H‐ZSM‐5‐(15)). Percent release of the drug‐loaded ZSM‐5 samples into simulated body fluid (SBF) was measured at pH 7.4 and 37°C. The results showed a slight variation in the % release within the range 84–93%, while the first‐order rate constant ( k ) varied from 2.2 h −1 for ZSM‐5‐(15) to 3.9 h −1 for H‐ZSM‐5‐(15). It was interesting to note that at the higher molar SiO 2 /Al 2 O 3 ratios of 169, both the sodium form, ZSM‐5‐(169), and the acid form, H‐ZSM‐5‐(169), exhibit an intermediate efficiency in either % loading (38%) or first‐order kinetic release constant ( k = 2.9 h −1 ).