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-4hydroxycinnamic 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, 1 H NMR, 13 C and 27 Al 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 death. 50 previously reported the preparation of a DDS based in zeolite Y 51 with an anticancer drug and demonstrated its efficacy against 52 colorectal carcinoma (CRC) cells in vitro. 22 CRC is the most 53 common type of tumor in Western countries, being men 54 slightly more often affected. 23 Treatment of CRC includes 55 surgery, radiotherapy, and/or chemotherapy. However, the 56 treatment design depends largely on the cancer stage. Despite 57 the progress made with the introduction of new cytotoxic 58 agents 24−28 and medical practices, survival rates of patients with 59 CRC changed little over the last 20 years, 29 justifying the need 60 for more effective therapies and new drugs. 61 α-Cyano-4-hydroxycinnamic acid (CHC) is a compound 62 derived from cinnamic acid and is a competitive inhibitor of 63 monocarboxylate transporter 1 (MCT1), 30 a protein recently 64 shown to be upregulated in colorectal and other cancers and 65 thus a potential target for cancer therapy. 31−33 Published data 66 demonstrated the cytotoxic and cytostatic effectiveness of 67 CHC, 34,35 both in vitro and in vivo. 36,37 CHC used here in a 68 model of colon carcinoma was chosen as a guest in two 69 different structures of zeolites for drug delivery. Due to their 70 structural properties, zeolites have attracted much research

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.

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Y and MOR zeolites were used as a host for the temozolomide (TMZ). Y presented toxicity to glioblastoma cancer cells in contrast to MOR. Higher potentiation of TMZ was obtained with MOR in comparison to free TMZ bothin vitroandin vivo.

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5-FU release profiles reveled to be dependent on the host structures. 5-FU DDS led to significant potentiation of the 5-FU effect in cancer cells.

The potential of salicylic acid (SA) encapsulated in porous materials as drug delivery carriers for cancer treatment was studied. Different porous structures, the microporous zeolite NaY and the mesoporous SBA-15 and MCM-41 were used as hosts for the anti-inflammatory drug. Characterization with different techniques (FTIR, UV/vis, TGA, 1 H NMR and 13 C CPMAS NMR) demonstrated the successful loading of SA into the porous hosts. The mesoporous structures showed to be very efficient to encapsulate the SA molecule. The obtained drug delivery systems (DDS) accommodated 0.74 mmol (341 mg/g ZEO ) in NaY and 1.07 mmol (493 mg/g ZEO ) to 1.23 mmol (566 mg/g ZEO ) for SBA-15 and MCM-41, respectively. Interactions between SA molecules and pore structures were identified. A fast and unrestricted liberation of SA at 10 min of the dissolution assay was achieved with 29.3, 46.6 and 50.1 µg/mL of SA from NaY, SBA-15 and MCM-41, respectively, in the in vitro drug release studies (PBS buffer pH 7.4, 37 ºC). Kinetic modeling was used to determine the release patterns of the DDS. The porous structures and DDS were evaluated on Hs578T and MDA-MB-468 breast cancer cell lines viability. The porous structures are non-toxic to cancer cells. Cell viability reduction was only observed after the release of SA from MCM-41 followed by SBA-15 in both breast cancer cell lines.

This study focusses on the development of a magnetic zeolite nanocomposite as a suitable platform towards the design of a theranostic system. Herein, we explored its ability to act as a T2-MRI contrast enhancer when magnetic nanoparticles are incorporated in its structure.