Tamoxifen/montmorillonite system – Effect of the experimental conditions

Silva, Dayanne T.C.; Arruda, Igor Eduardo Silva; França, L.M. de; França, D.B.; Fonseca, Maria G.; Soares, Mônica F.L.R.; Iborra, César Viseras; Sobrinho, José Lamartine Soares

doi:10.1016/j.clay.2019.105142

Cited by 16 publications

(8 citation statements)

References 47 publications

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“…After the addition of MMT to CS, the diffraction was found at 14.40° (2θ). In agreement with previous studies [48, 52], the initial band intensity in CS was much broader compared to that of CS‐MMT, suggesting the amorphous nature of silica sheets in MMT. The band shift from a higher diffraction angle (20.14°) to a lower diffraction angle (14.40°) decreased the band intensity of CS‐MMT compared to CS.…”

Section: Resultssupporting

confidence: 92%

Preparation of a pH‐responsive chitosan‐montmorillonite‐nitrogen‐doped carbon quantum dots nanocarrier for attenuating doxorubicin limitations in cancer therapy

Rahmani

Pourmadadi

Ghorbanian

et al. 2022

Engineering in Life Sciences

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Despite its widespread usage as a chemotherapy drug in cancer treatment, doxorubicin (DOX) has limitations such as short in vivo circulation time, low solubility, and poor permeability. In this regard, a pH-responsive chitosan (CS)-montmorillonite (MMT)-nitrogen-doped carbon quantum dots (NCQDs) nanocomposite was first developed, loaded with DOX, and then incorporated into a double emulsion to further develop the sustained release. The incorporated NCQDs into the CS-MMT hydrogel exhibited enhanced loading and entrapment efficiencies. The presence of NCQDs nanoparticles in the CS-MMT hydrogel also resulted in an extended pH-responsive release of DOX over a period of 96 h compared to that of CS-MMT-DOX nanocarriers at pH 5.4. Based on the Korsmeyer-Peppas model, there was a controlled DOX release at pH 5.4, while no diffusion was observed at pH 7.4, indicating fewer side effects. MTT assay showed that the cytotoxicity of DOX-loaded CS-MMT-NCQDs hydrogel nanocomposite was significantly higher than those of free DOX (p < 0.001) and CS-MMT-NCQDs (p < 0.001) on MCF-7 cells. Flow cytometry results demonstrated that a higher

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Section: Resultssupporting

confidence: 92%

Preparation of a pH‐responsive chitosan‐montmorillonite‐nitrogen‐doped carbon quantum dots nanocarrier for attenuating doxorubicin limitations in cancer therapy

Rahmani

Pourmadadi

Ghorbanian

et al. 2022

Engineering in Life Sciences

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“…This saturation is because of the high initial adsorption of RIF molecules by the adsorbent because, in shorter contact times, rapid competition for active sites leads to a decrease in the amount of active sites available. 77 As previously discussed, the way the molecule is found in the medium (neutral, cationic, or anionic) depends on the pH and, consequently, the characteristics of the adsorption process are affected. Therefore, as RIF has its totality in its cationic form at pH 2, it showed high incorporation efficiency values (almost 100%).…”

Section: ■ Results and Discussionmentioning

confidence: 47%

“…The system is in equilibrium after 180 min, and saturation can be observed in longer contact times, which results in a slower adsorption process. This saturation is because of the high initial adsorption of RIF molecules by the adsorbent because, in shorter contact times, rapid competition for active sites leads to a decrease in the amount of active sites available …”

Section: Resultsmentioning

confidence: 99%

Obtaining and Applying Nanohybrid Palygorskite-Rifampicin in the pH-Responsive Release of the Tuberculostatic Drug

et al. 2020

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Despite having good efficacy in the treatment and prevention of tuberculosis, the administration of rifampicin (RIF) can cause serious side effects, resulting from the prolonged use of this substance. Thus, it is necessary to seek new systems for administering tuberculostatic drugs, to avoid unwanted adverse effects, increase their bioavailability and, consequently, improve their therapeutic efficacy. The present work describes the achievement of a pH-responsive system for RIF, using palygorskite, a fibrous clay mineral, as a nanocarrier. To evaluate the influence of some operational variables on the drug adsorption process, a 2 4 factorial experimental design was used. The experiment using a maximum concentration (0.125 mg/mL), lower mass of PAL (300 mg), and lower pH (pH 2) was more efficient compared to other experiments, resulting in a higher dose of the incorporated drug, equivalent to 33.62 mg/g. To elucidate the mechanism of interaction between the materials, the hybrid obtained was characterized by different characterization techniques (Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetry/derived thermogravimetry, zeta potential, scanning electron microscopy, and dispersive energy spectroscopy). In addition, kinetic models and adsorption isotherms were applied to the experimental data. Through in vitro release studies, it was possible to verify the effectiveness of the pH-dependent system obtained. The adjustment of experimental release data to the theoretical model of Higuchi indicated that the release of rifampicin occurs in a prolonged way from the palygorskite.

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“…The three clay minerals exhibited characteristic bands in similar regions and were differentiated by the intensities and bandwidths in the main areas that characterize the materials. These areas are related to tetrahedral sheets Si-O-Si (950–1250 cm −1 ) and M-OH octahedral (M indicates a metal, e.g., Al–Al–OH, Mg–Mg–OH, Al–Fe–OH) that appear in the low-wavelength region as well as bands attributed to hydroxyls and water molecules that appear between 3200–3440 cm −1 and 1650 cm −1 , respectively [22,24,32,34,35,36,37,38,39].…”

Section: Resultsmentioning

confidence: 99%

Understanding Urea Encapsulation in Different Clay Minerals as a Possible System for Ruminant Nutrition

et al. 2019

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Considering the challenges of urea administration due to the high ureolytic activity of the rumen and the importance of its use, as well as taking into account the relevance of sustainably exploiting the technological potential of biodiversity, this research studies the encapsulation of urea in different clay minerals (palygorskite (Pal), sepiolite (Sep), and Veegum® (V)) as an alternative for use as nonprotein nitrogen (NNP) sources. A method of incorporation was developed in which the encapsulation of urea was proven by X-ray diffraction; fibrous materials, Pal and Sep had similar characteristics due to the decrease in the relative plane intensity (011), suggesting a decrease in the order of their stacking due to the presence of urea on the surface or inside channels. By contrast, V showed a 7.74° reflection shift, suggesting an increase in basal spacing from 11.45 Å in V to 14.88 Å in the sample after urea encapsulation. By thermogravimetry, it was observed that the presence of urea did not change the mass-loss profiles but only increased the percentage of loss in respective events, indicating urea incorporation in the clay minerals. These results provide a promising alternative for administering NNP sources in the ruminant diet.

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Tamoxifen/montmorillonite system – Effect of the experimental conditions

Cited by 16 publications

References 47 publications

Preparation of a pH‐responsive chitosan‐montmorillonite‐nitrogen‐doped carbon quantum dots nanocarrier for attenuating doxorubicin limitations in cancer therapy

Preparation of a pH‐responsive chitosan‐montmorillonite‐nitrogen‐doped carbon quantum dots nanocarrier for attenuating doxorubicin limitations in cancer therapy

Obtaining and Applying Nanohybrid Palygorskite-Rifampicin in the pH-Responsive Release of the Tuberculostatic Drug

Understanding Urea Encapsulation in Different Clay Minerals as a Possible System for Ruminant Nutrition

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