The studies of potentiation of
5-fluorouracil (5-FU), a traditional
drug used in the treatment of several
cancers, including colorectal (CRC), were carried out with
zeolites Faujasite in the
sodium form, with different particle sizes (NaY, 700nm and nanoNaY, 150nm) and Linde type L in the
potassium form (LTL) with a particle size of 80nm.
5-FU was loaded into
zeolites by liquid-phase adsorption. Characterization by spectroscopic techniques (FTIR, (1)H NMR and (13)C and (27)Al solid-state MAS NMR), chemical analysis, thermal analysis (TGA),
nitrogen adsorption isotherms and scanning electron microscopy (SEM), demonstrated the successful loading of
5-FU into the
zeolite hosts. In vitro drug release studies (PBS
buffer pH 7.4, 37°C) revealed the release of 80-90% of
5-FU in the first 10min. To ascertain the drug release kinetics, the release profiles were fitted to zero-order, first-order, Higuchi, Hixson-Crowell, Korsmeyer-Peppas and Weibull kinetic models. The in vitro dissolution from the drug delivery systems (DDS) was explained by the Weibull model. The DDS efficacy was evaluated using two human
colorectal carcinoma cell lines, HCT-15 and RKO. Unloaded
zeolites presented no toxicity to both
cancer cells, while all DDS allowed an important potentiation of the
5-FU effect on the cell viability. Immunofluorescence studies provided evidence for
zeolite-cell internalization.