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)

SINGLE VIBRONIC LEVEL EMISSION SPECTROSCOPY OF JET-COOLED HALOSILYLENES (HSiF, HSiCl, and HSiBr)

$^{a}$H. Harjanto, W. W. Harper, and D. J. Clouthier, J. Chem. Phys. 105, 10189 (1996). $^{b}$W. W. Harper, D. A. Hostutler, and D. J. Clouthier, J. Chem. Phys. 106, 4367 (1997). $^{c}$W. W. Harper, and D. J. Clouthier, J. Chem. Phys. 106, 9461 (1997).Author Institution: Department of Chemistry, University of Kentucky, Lexington, KY; Department of Chemistry, Centre College, Danville, KY 40422-1309; Department of Chemistry, University of Wisconsin-Parkside, Kenosha, WIUsing the technique of single vibronic level emission spectroscopy, the ground state vibrational manifolds of HSiF, HSiCl, and HSiBr and their deuterated analogs have been studies. The silylenes were produced in a pulsed electric discharge jet with the appropriate halosilane $(HSiX_{3})$ as the precursor. The gas phase harmonic vibrational frequencies and anharmonicities have been determined for the first time and the ground state harmonic force fields have been obtained for all three species. Our previous ground state rotational $constants^{a b c}$ have been determined with the calculated harmonic contributions to the $\alpha$ constants to obtain average $(r_{z})$ structures and estimates of the equilibrium $(r^{z}_{e})$ structues. The reliability of the force constants has been evaluated by Franck-Condon simulations of the emission spectra and comparisons of the calculated and experimentally determined inertial defects