Zeolite structures loading with an anticancer compound as drug delivery systems

The authors are thankful to Dr. A. S. Azevedo for collecting the powder diffraction data.Two different structures of zeolites, faujasite (FAU) and Linde type A (LTA), were studied to investigate their suitability for drug delivery systems (DDS). The zeolites in the sodium form (NaY and NaA) were used as hosts for encapsulation of α-cyano-4- hydroxycinnamic acid (CHC). CHC, an experimental anticancer drug, was encapsulated in both zeolites by diffusion in liquid phase. These new drug delivery systems, CHC@zeolite, were characterized by spectroscopic techniques (FTIR, 1H NMR, 13C and 27Al solidstate MAS NMR, and UV−vis), chemical analysis, powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The effect of the zeolites and CHC@zeolite drug deliveries on HCT-15 human colon carcinoma cell line viability was evaluated. Both zeolites alone revealed no toxicity to HCT-15 cancer cells. Importantly, CHC@zeolite exhibit an inhibition of cell viability up to 585-fold, when compared to the non-encapsulated drug. These results indicate the potential of the zeolites for drug loading and delivery into cancer cells to induce cell deathO.M. and R.A. are recipients of fellowships (SFRH/BD/36463/2007, SFRH/BI/51118/2010) from Fundação para a Ciência e a Tecnologia (FCT, Portugal). This work was supported by the FCT projects refs PEst-C/ QUI/UI0686/2011, PEst-C/CTM/LA0011/2011, and PTDC/ SAU-FCF/104347/2008, under the scope of “Programa Operacional Temático Factores de Competitividade” (COMPETE) of “Quadro Comunitário de Apoio III” and cofinanced by Fundo Comunitário Europeu FEDER, and the Centre of Chemistry and Life and Health Sciences Research Institute (University of Minho, Portugal)

Encapsulation of α-cyano-4-hydroxycinnamic acid into a NaY zeolite

The authors are thankful to Dr. K. Biernacki for DFT calculations and Dr. A.S. Azevedo for collecting the powder diffraction data.The faujasite zeolite structure was studied to investigate its suitability for development of new drug delivery systems (DDS). The sodium form (NaY) of the zeolite was used for encapsulation of a-cyano-4-hydroxy-cinnamic acid (CHC), an experimental anticancer drug used in colorectal cancer therapy. The DDS was prepared by diffusion in liquid phase of CHC as a guest in the void space of the host zeolite structure at pH 7.0. The molecular integrity of CHC in the encapsulation process was evaluated by proton nuclear magnetic resonance spectroscopy(1H NMR) and Ultraviolet–Visible spectroscopy (UV–Vis). The new drug delivery system, CHC@NaY, was characterized by Fourier transform infrared spectroscopy and UV–Vis, chemical analysis, powder X-ray diffraction, and Scanning electron microscopy. Analysis of the data of the drug alone and encapsulated in NaY show that CHC and the zeolite framework preserved their original structure. The effect of the zeolite and DDS on HCT-15 human colon carcinoma cell line viability was evaluated. The encapsulation of CHC significantly increased its potency.OM and RA are recipients of fellowships (SFRH/BD/ 36463/2007, SFRH/BI/51118/2010) from Fundacão para a Ciência e Tecnologia (FCT, Portugal).This study was supported by the Centre of Chemistry and Life and Health Sciences Research Institute (ICVS), University of Minho, Portugal, FCT (Portugal) through POCTI and FEDER projects (ref. POCTI-SFA-3-686) and by the FCT grant ref. PTDC/SAU-FCF/104347/2008, under the scope of ‘‘Programa Operacional Temático "Factores de Competitividade’’ (COMPETE) of ‘‘Quadro Comunitário de Apoio III’’ and co-financed by Fundo Comunitário Europeu FEDER

Influence of solvent properties on the electrical response of poly(vinylidene fluoride)/NaY composites

Different solvents were used for the preparation of poly(vinylidene fluoride), PVDF, and NaY zeolite composites by solvent casting and melt crystallization. Solvents like N,N-dimethylformamide (DMF) and dimethylsulphoxide (DMSO) and triethyl phosphate (TEP) were chosen as they present different dielectric constants and can be encapsulated in the porous structure of NaY zeolite introduced in the PVDF/zeolite composites. The solvent molecules encapsulated induce variations in the dielectric response of the composite films according to the solvent dielectric constant. In this way, the solvent with the higher dielectric constant, DMSO, results in the composite with higher dielectric constant, while the opposite happens with TEP. The solvent molecules modify the distribution of intra zeolite cations increasing the dielectric constant of the composite. The zeolite also contribute to the increase of the d.c. conductivity, which is characterized by a double regime indicated by a breaking voltage, which value decreases when the dielectric constant of the solvent increases.This work is supported by the Center of Physics and by the Center of Chemistry and is funded by FEDER funds through the "Programa Operacional Factores de Competitividade – COMPETE" and by national funds by FCT- Fundação para a Ciência e a Tecnologia, project references NANO/NMed-SD/0156/2007, PTDC/CTM-NAN/112574/2009, PEST-C/FIS/UI607/2011 and PEst-C/QUI/UI0686/2011. ACL thanks the FCT for the grant SFRH/BD/62507/2009. The authors also thank support from the COST Action MP1003, the ‘European Scientific Network for Artificial Muscles’ (ESNAM)