resumo
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, 700 nm and nanoNaY, 150 nm) and Linde type L in the potassium form (LTL) with a particle size of 80 nm. 5-FU was loaded into zeolites by liquid-phase adsorption. Characterization by spectroscopic techniques (FTIR, H-1 NMR and C-13 and Al-27 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 degrees C) revealed the release of 80-90% of 5-FU in the first 10 min. 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. (C) 2013 Elsevier B.V. All rights reserved.
palavras-chave
SYNTHETIC ZEOLITES; CANCER; RELEASE; NANOPARTICLES; CAPECITABINE; FLUOROURACIL; RELAXIVITY; THERAPY; HY
categoria
Biophysics; Chemistry; Materials Science
autores
Vilaca, N; Amorim, R; Machado, AF; Parpot, P; Pereira, MFR; Sardo, M; Rocha, J; Fonseca, AM; Neves, IC; Baltazar, F
nossos autores
João Rocha
Prof. Catedrático
Mariana Coutinho Sardo
Investigador Auxiliaragradecimentos
RA is recipient of fellowship SFRH/BI/51118/2010 from Fundacao para a Ciencia e a Tecnologia (FCT, Portugal). This work was supported by the FCT projects refs. PEst-C/QUI/UI0686/2011 and PEst-C/CTM/LA0011/2011 and the Centre of Chemistry and Life and Health Sciences Research Institute (University of Minho, Portugal). The NMR spectrometer is part of the National NMR Network (RNRMN), supported with funds from FCT/QREN (Quadro de Referencia Estrategico Nacional).