Efficient Enhancement in Itraconazole Solubility through its Cyclodextrin-Water Soluble Polymer Ternary Inclusion Complexes

The aim of this work is the enhancement of the hydrosolubility behaviour of a poorly soluble, weakly basic drug, using itraconazole (ITZ) as a case example. Binary inclusion complexes of ITZ with β-cyclodextrin (β-CD) are prepared in 1:2 molar ratios of ITZ to β-CD by co-evaporation method. Both solubility and dissolution behaviour are compared with that of the pure drug. Ternary complexes can be obtained by adding the polyvinylpirrolidone (PVP) which is a highly water soluble polymer, in the ITZ/ β-CD complex formation. Actually, Solid state analysis is performed for all formulations and for pure ITZ applying the Fourier transforms infrared (FT-IR) spectroscopy, powder X-ray diffraction (pX-RD) and differential scanning calorimetry (DSC). Solubility tests indicate that with all formulation, the solubility of ITZ formed with β-CD or β-CD and PVP proved to be increased. The obtained results show that the pure drug has a poor dissolution property, and the ternary inclusion complexes resulted in fast and extensive release of ITZ. Keywords: Itraconazole, β-cyclodextrin, polyvinylpyrrolidone

Adsorption of rhodamine 6G and humic acids on composite bentonite-alginate in single and binary systems

In this work, the preparation, characterization, and sorption of rhodamine 6G and humic acids on a composite sodium alginate-bentonite were investigated. Their structure and morphology were analyzed by several techniques, including Fourier transform infrared spectroscopy, X-ray diffraction, and N-2 adsorption at - 196 degrees C. A synergetic sorption mechanism was observed in binary systems; humic acids adsorption was enhanced by the presence of Rh6G in the mixture. The kinetic studies revealed that the sorption follows a pseudo-first-order kinetic model and the sorption capacities of Rh6G increased with the pH value. The Langmuir isothermal model well described the adsorption isotherm data, showing a maximum adsorption capacity for Rh6G up to 429.5 mg/g at 20 degrees C. On the basis of the data of the present investigation, it is possible to conclude that the composite exhibited excellent affinity for the dye and humic acids, and it can be applied to treat wastewater containing dye and natural organic matter.AG is grateful for financial support from Santander Bank through the Research Intensification Program

Synthesis and characterization of ZnAl-layered double hydroxide and organo-K10 montmorillonite for the removal of diclofenac from aqueous solution

Two prepared adsorbents, namely, calcined ZnAl-layered double hydroxide and K10 montmorillonite intercalated with cetyltrimethyl-ammonium bromide cations are used in diclofenac sodium adsorption under the batch reactor operations. The pseudo-second-order model describes better the results of the kinetics. Fitting parameters revealed that the rate of adsorption increased with the increase in diclofenac sodium concentration and decrease in background electrolyte concentration and temperature, while the solution pH did not have a significant effect. The maximum adsorption capacities of diclofenac obtained by Langmuir model are found to be 55.46 and 737.02 mg/g for K10 montmorillonite intercalated with cetyltrimethyl-ammonium bromide cations and ZnAl-C LDH, respectively. The results of adsorption–desorption cycles revealed that ZnAl-C LDH and K10 montmorillonite intercalated with cetyltrimethyl-ammonium bromide cations have an excellent potential to be used as an economical adsorbent for the removal of diclofenac sodium from water

Kinetics, thermodynamics, equilibrium isotherms and reusability studies of cationic dye adsorption by magnetic alginate/oxidised multiwall carbon nanotubes composites

Magnetic beads (AO-γ-Fe 2 O 3 ) of alginate (A) impregnated with citrate coated maghemite nanoparticles (γ-Fe 2 O 3 ) and oxidized multiwalled carbon nanotubes (OMWCNTs) were synthesized and used as adsorbent for the removal of methylene blue from water. The XRD analysis revealed that the diameter of γ-Fe 2 O 3 is 10.24 nm. The mass saturation magnetization of AO-γ-Fe 2 O 3 and γ-Fe 2 O 3 were found to be 27.16 and 42.63 emu·g −1 , respectively. The adsorption studies revealed that the data of MB isotherm were well fitted to the Freundlich model. The Langmuir isotherm model exhibited a maximum adsorption capacity of 905.5 mg·g −1 . The adsorption was very dependent on initial concentration, adsorbent dose, and temperature. The beads exhibited high adsorption stability in large domain of pH (4–10). The thermodynamic parameters determined at 283, 293, 303, and 313 K revealed that the adsorption occurring was spontaneous and endothermic in nature. Adsorption kinetic data followed the intraparticle diffusion model. The AO-γ-Fe 2 O 3 beads were used for six cycles without significant adsorptive performance loss. Therefore, the eco-friendly prepared AO-γ-Fe 2 O 3 beads were considered as highly recyclable and efficient adsorbent for methylene blue as they can be easily separated from water after treatment

Maghemite/alginate/functionalized multiwalled carbon nanotubes beads for methylene blue removal: Adsorption and desorption studies

Magnetic alginate beads (A-Fe2O3) and magnetic alginate functionalized multiwalled carbon nanotubes beads (A-F-Fe2O3) were synthesized using citrate coated maghemite nanoparticles (γ-Fe2O3). Vibrating sample magnetometry analysis showed that the mass saturation magnetization of A-F-Fe2O3, A-Fe2O3, and γ-Fe2O3 is equal to 27.16, 29.06, and 42.63 emu·g−1, respectively. Compared with A-Fe2O3 beads, A-F-Fe2O3 beads showed a better adsorption performance for MB removal with a maximum monolayer adsorption capacity of qm = 905.5 mg·g−1. The adsorption studies revealed that the data of MB adsorption isotherm onto A-F-Fe2O3 were well fitted by Freundlich model. The adsorption was ionic strength and initial dye concentration-dependent. The beads presented high stability of MB adsorption capacity in a large domain of pH. Adsorption kinetic data followed the intraparticle diffusion model. Regeneration experiments were performed using five different desorbing agent. The findings reveal that magnetic A-F-Fe2O3 beads present an ideal and cost effective adsorbent in large-scale application as it demonstrated high affinity and reusability for methylene blue dye and facilitate an easy separation after treatment

Effective Adsorption of Methylene Blue dye onto Magnetic Nanocomposites. Modeling and Reuse Studies

In the present study, new adsorbent beads of alginate (A)/maghemite nanoparticles (γ-Fe2O3)/functionalized multiwalled carbon nanotubes (f-CNT) were prepared and characterized by several techniques, e.g., N2 adsorption-desorption isotherms, Fourier transformed infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA/DTG), scanning electron microscopy (SEM), and vibrating sample magnetometry (VSM) and further tested for the adsorption of the dye methylene blue (MB) from water. The beads (A/γ-Fe2O3/f-CNT) presented a relatively low BET specific surface area value of 59 m2g−1. The magnetization saturation values of A/γ-Fe2O3/f-CNT beads determined at 295 K was equal to 27.16 emu g−1, indicating a magnetic character. The time needed to attain the equilibrium of MB adsorption onto the beads was estimated within 48 h. Thus, several kinetic and isotherm equation models were used to fit the kinetic and equilibrium experimental results. The number of adsorbed MB molecules per active site, the anchorage number, the receptor sites density, the adsorbed quantity at saturation, the concentration at half saturation and the molar adsorption energy were quantified using the monolayer model. The calculated negative ΔG0 and positive ΔH0 values suggested the spontaneous and endothermic nature of the adsorption process. In addition, A/γ-Fe2O3/f-CNT composites can be used at least for six times maintaining their significant adsorptive performance and could be easily separated by using a magnet from water after treatment

Adsorption studies of an azo dye using polyaniline coated calcined layered double hydroxides

International audienceIn this study, novel composite polyaniline/calcined layered double hydroxides was synthesized through the chemical method using the ammonium persulfate as an oxidant and investigated for its behavior in selective and high adsorption of tartrazine dye from an aqueous solution in a batch system. Scanning electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction, Brunauer–Emmett–Teller method and thermogravimetric analysis were carried out. The effects of solution pH, initial concentration and contact time were investigated. The adsorption processes show that the max-imum adsorption capacity of tartrazine was 487.8 mg/g, obtained for the MgAlC-PANI composite and well fitted to Langmuir isotherm model. The adsorption processes followed the pseudo-second-order kinetics model with a very high correlation coefficient of 0.998 < R2 < 1. The regeneration studies revealed that the tartrazine loaded MgAlC-PANI could be reused for four consecutive cycles