X-ray Powder Diffractograms Research Articles

Effect of Biopolymer on the Dissolution and Stability of Itraconazole

traconazole (ITZ) polyethylene glycol 4000 (PEG) solid dispersions (SDs) containing hydroxypropyl methylcellulose (HPMC) and/or low methoxy pectin (LMP) were prepared by melting method at a ratio of drug to carrier of 1:9. ITZPEG formulations showed the highest drug release (83.51%) when compared to the formulations containing HPMC and/or pectin (i.e., 43.02%, 40.64% and 59.94% for those containing HPMC, LMP and HPMC+LMP, respectively). Powder X-ray diffractograms of all formulations revealed that the drug was present in an amorphous form while a crystalline form was observed only in ITZ or its physical mixture. After storage at accelerated condition (40°C, 75%RH) for 2 and 12 months, the crystalline of ITZ was clearly not observed in all SDs. All formulations showed an increase in mean dissolution time (MDT) but the formulations containing biopolymer showed the lower MDT than that containing no biopolymer. The results suggested that either HPMC or LMP in SDs can help to inhibit the recrystallization of amorphous ITZ in SD, probably by a polymer anti-plasticizing effect.

Microwave, sonochemical and combustion synthesized CuO nanostructures and their electrical and bactericidal properties

Abstract Cetyltrimethylammonium bromide (CTAB)-assisted microwave synthesis of CuO provides nanoleaves and in the absence of CTAB the shape of CuO is irregular. Sonochemical synthesis of CuO using CTAB gives nanodiscs whereas irregularly shaped flake-like structure is obtained without CTAB. Combustion synthesized CuO is highly porous with innumerable large holes. CTAB does not provide any structure in combustion synthesis. Transmission electron micrographs (TEM) display the constituent nanoparticles of microwave and sonochemically synthesized CuO. The powder X-ray diffractogram (XRD) shows the sample obtained by sonochemical method in the absence of CTAB as a mixture of monoclinic CuO, cubic Cu2O, and orthorhombic Cu(OH)2. But the rest of the samples are pure CuO in monoclinic phase. The selected area electron diffractograms (SAED) of the microwave and sonochemically synthesized samples, in the presence as well as in the absence of CTAB, confirm the monoclinic phase of CuO and indicates the presence of amorphous CuO in traces. All the samples are characteristic of Fourier Transform infrared (FT-IR) Cu–O stretching frequencies. The method of synthesis and also the morphology influence the electrical properties as well as the bactericidal activity of CuO.

Microstructural evolution of ball-milled Mg–Ni powder during hydrogen sorption

Ball-milling of Mg75Ni25 powder blends were carried out in a SPEX-8000 shaker mill. The morphology and microstructure of the milled powders were studied by scanning electron microscopy and X-ray diffraction, respectively. The dehydrogenation process of the sample milled for 10 h was stopped at different hydrogen contents (25, 50 and 75 percent of the maximum capacity) in a Sieverts' type apparatus, in order to achieve partially desorbed states. For comparison, the fully hydrided (100 percent) and the fully dehydrided (0 percent) states were also obtained. Convolutional multiple whole profile fitting analysis of the corresponding X-ray powder diffractograms was carried out in order to monitor the evolution of microstructural parameters during desorption, such as average coherent crystallite size and size distribution of two hydrides (Mg2NiH4 and Mg2NiH0.3) that nucleate during the hydrogenation of Mg–Ni powders. The desorption induced changes in the relative amount of the hydride phases were also quantified.

Water Sorption Cycle Measurements on Functionalized MIL-101Cr for Heat Transformation Application

The water loading capacity and water cycle stability (40 adsorption/desorption cycles) of four nitro- or amino-functionalized MIL-101Cr materials (1–4) is assessed for heat transformation applications. Amino- or nitro-functionalized (1, 3) and partially amino- or nitro-functionalized MIL-101Cr (2, 4) have been synthesized through time-controlled postsynthetic modification of MIL-101Cr. The partially functionalized materials (2, 4) contain about 78 mol % amino- or nitro-functionalized terephthalate linker. Hydrophilic nitro or amino functionalities were introduced into MIL-101Cr in order to achieve water loading at lower p/p0 values for possible use in thermally driven adsorption chillers or heat pumps. Among the four materials studied, fully aminated MIL-101Cr-NH2, 1, and partially aminated MIL-101Cr-pNH2, 2, showed the best water loadings (about 1.0 gH2O/gMIL) as well as water stability over 40 adsorption–desorption cycles. After 40 cycles, the X-ray powder diffractogram and Brunauer–Emmett–Teller (BET) surface determination of amino-functionalized materials indicated structural integrity with ΔBET = −6.3% after 40 cycles, while the nitro-functionalized MIL-101Cr exhibited a decrease in their BET surface of ΔBET = −25% and −20% for 3 and 4, respectively.

The enhanced photocatalytic and bactericidal activities of carbon microsphere-assisted solvothermally synthesized cocoon-shaped Sn4+-doped ZnO nanoparticles

Cocoon-shaped Sn(4+)-doped ZnO nanoparticles have been synthesized by a solvothermal method using carbon microspheres as a template. The optimum doping level for photocatalysis is 3% (g. atom). Powder X-ray diffractograms show that the ZnO has a primitive hexagonal crystal structure and that doping ZnO with Sn(4+) increases the unit cell lengths and the Zn-O bond lengths. Larger crystal growth along the c-axis is also observed. The measured size of the cocoon-shaped Sn(4+)-doped ZnO nanoparticles is larger than the mean crystallite size. Solid state impedance spectroscopy studies reveal that Sn(4+)-doping increases the charge transfer resistance. Doping does not significantly modify the optical band gap, but does suppress green emission. A decrease in the number of crystal defects due to oxygen vacancies is likely to be a reason for the enhanced photocatalytic properties of the cocoon-shaped Sn(4+)-doped ZnO nanoparticles. Doping ZnO with Sn(4+) enhances the bactericidal activity as well.

Cu2S@ZnO hetero-nanostructures: facile synthesis, morphology-evolution and enhanced photocatalysis and field emission properties

A novel hierarchical three-dimensional (3D) Cu2S@ZnO heteroarchitecture was successfully synthesized by a facile three-step synthetic process. FESEM and TEM analyses revealed the formation of the hierarchical 3D structure of the as-prepared Cu2S@ZnO. The purity and crystalline phase of the individual component in the 3D Cu2S@ZnO were determined by a powder X-ray diffractogram. The formation of the hierarchical 3D structure of the as-prepared Cu2S@ZnO leads to multiple p–n junctions formed at p-Cu2S@n-ZnO interfaces, which promote the generation and separation of photoinduced electrons and holes and thus improves the photocatalytic efficiency tremendously. According to the data, after irradiation for 40 min, the remaining MB in solution is about 35% for Cu2S nanoflowers and 9% for Cu2S@ZnO binary nanoflowers. Also, the increases in the overall aspect ratio and the ZnO nanoparticles act as extra emission sites, which help to enhance the field emission properties. The turn-on fields and threshold fields for the Cu2S nanoflowers as well as the Cu2S@ZnO nanoflower hybrid emitters are 3.3 and 9.2 V μm−1, 2 and 6.3 V μm−1, respectively. Compared with the Cu2S nanoflowers, the Cu2S@ZnO hetero-nanoflowers show excellent improvements in both photocatalytic and field emission applications.

Optical, Electrical, and Photocatalytic Characteristics of Sol-Gel–Derived CuO-TiO2 Nanocomposite

CuO-TiO2 nanocomposite prepared by sol-gel method does not photocatalyze dye degradation under UV-A as well as visible light. Powder X-ray diffractogram shows the presence of monoclinic CuO and anatase TiO2 in the nanocomposite. The composite displays photoconductance confirming photogeneration of charge carriers. Absence of photocatalysis is attributed to CuO-mediated electron-hole recombination.

Sol–gel chemistry synthesis and DTA–TGA, XRPD, SIC and 7Li, 31P, 29Si MAS–NMR studies on the Li-NASICON Li3Zr2−ySi2−4yP1+4yO12 (0 ⩽ y ⩽ 0.5) system

Five selected compounds of Li-NASICON, Li3Zr2−ySi2−4yP1+4yO12 (0⩽y⩽0.5), were synthesized by sol–gel chemistry in order to obtain pure polycrystalline powder and then analyzed by different physicochemical characterizations such as coupled DTA (differential thermal analysis)–TGA (thermogravimetric analysis), XRPD (X-ray powder diffraction), CIS (complex impedance spectroscopy) and MAS (magic angle spinning)–NMR (nuclear magnetic resonance). So the calcined temperature of each sample has been deduced from its corresponding DTA–TGA thermogram. However, the recorded X-ray powder diffractograms were indexed in the rhombohedral system with R3¯c space group which corresponds to the ideal structure of NASICON. Whereas, the complex impedance spectroscopy study showed that these Li-NASICON materials are excellent lithium fast cation conductors with total electric conductivity maximal value 1.97×10−3Scm−1 at 293K in the case of Li3Zr1.5P3O12. Furthermore, 7Li, 31P and 29Si MAS–NMR spectroscopy study and DFT/B3LYP theoretical calculations of chemical shifts were performed to discuss the ambiguousness that exists between the resonance peak number in the experimental spectrum and the crystallographic site number relative to Li3Zr2Si2PO12.

Study on Transport Properties of Bi2Se3 Single Crystals Grown by Vapor Phase Technique

Single crystals of Bi2Se3 were grown by vapor phase technique using ammonium chloride (NH4Cl) as a transporting agent. The stoichiometry of the as-grown Bi2Se3 crystal was confirmed by energy-dispersive analysis of X-ray. The lattice parameters, crystallite size, and stacking fault probabilities were determined from X-ray powder diffractogram. The surface morphology of the as-grown single crystals was studied using AFM image. The Seebeck coefficient and resistivity variation from low (6 K) to near ambient temperature on these as-grown Bi2Se3 single crystals was measured. The Hall effect measurements were carried out at three different low temperatures. The obtained results are discussed in detail.

Comparative Study on the Properties of BTCS and BTCZS Crystals Grown by Slow Evaporation Method

Good quality Bisthiourea Cadmium Sulphate (BTCS) and Bisthiourea Cadmium Zinc Sulphate (BTCZS) crystals have been grown by simple slow evaporation method. The grown crystals were found to be transparent in the entire visible region. From the powder X-ray diffractograms it is concluded that BTCS crystal belongs to orthorhombic system, whereas BTCZS crystals belong to monoclinic system. From the FTIR comparative study of BTCS and BTCZS, it is observed that when Zinc is added into BTCS crystal, there is a decrease in the frequency of symmetric C=S stretching and an increase in the frequency of N-H asymmetric stretching vibration. UV-Vis studies show that the grown crystals have high transparency in entire visible region. The Vicker’s microhardness results show that the addition of Zinc with Bisthiourea Cadmium Sulphate reduces the hardness of the crystal.

Novel pectin-based nanoparticles prepared from nanoemulsion templates for improving in vitro dissolution and in vivo absorption of poorly water-soluble drug

The purpose of this study was to improve in vitro dissolution and in vivo absorption of itraconazole (ITZ), a poorly water-soluble drug, by means of novel pectin-based nanoparticles prepared from nanoemulsion templates. Nanoemulsion templates were prepared by a high-pressure homogenization using pectin (i.e., 0.5–3.0%w/w low-methoxyl pectin (LMP), amidated low-methoxyl pectin (ALMP), or high-methoxyl pectin (HMP)) as an emulsifier and chloroform as an oil phase. HMP provided good oil-in-water emulsions with ITZ loaded in the oil phase. The chloroform in nanoemulsions was then removed to produce the suspensions of nanoparticles dispersed in water phase. After lyophilization, the dried core–shell nanoparticles with good properties in terms of redispersibility, dissolution, and stability were obtained. The alteration of ITZ crystallinity was clearly observed from powder X-ray diffractogram while no interaction between ITZ and pectin was found in the nanoparticles. The ITZ-loaded nanoparticles showed high percent drug dissolved, especially those prepared from HMP, and could maintain their good dissolution properties even after 6-month storage. The in vivo absorption study in fasted rats demonstrated that pectin-based nanoparticles prepared from nanoemulsion templates could improve absorption of ITZ, that is, 1.3-fold higher than the ITZ commercial product (p<0.05). Pectin type highly influenced the dissolution properties and also in vivo plasma profile. These findings suggested that HMP-based nanoparticles seem to be a promising formulation due to their high AUC0–24h and Cmax.

Purification and Characterization of a Natural Brazilian Clay Blend

Clay blends are products used in several industrial sectors, such as petrochemical or pharmaceutical. In this work we describe a natural clay blend occurring in northeastern Brazil. The aim was to purify and investigate their rheological and physical-chemical properties. Foster essays with water and organic solvents were utilized to access the swelling properties of the analyzed sample. Powder X-ray diffractograms (PXRD) were utilized to analyze qualitatively the clay minerals presents in the sample blend. Scanning eletronic microscopy (SEM) and Malvern techniques were used to investigate the sample clay morphology. The purification proceeding allowed separate distinct clay phases with different colors. PXRD analysis demonstrated that each clay phase presents similar structure. SEM and Malvern analysis showed distinct morphology and different size distribution for each clay phase. Our results revealed that the analyzed sample clay may be classified as smectite blend with strong potential for use in pharmaceutical and cosmetic products.

Feasibility study on cross-linked biopolymeric concrete encapsulating selenium glass wastes

Feasibility study was conducted to encapsulate the selenium (Se) contained in glass waste, using the biopolymer-modified concrete. Biopolymer has unique characteristics to provide the chemical sites to metals or toxic compounds through the three-dimensional cross-linked structure. Very minute amount of biopolymer enhanced the characteristics of cementitious material. The resulting biopolymeric composite with selenium glass waste showed 20% higher compressive strength than ordinary concrete and the lower leaching concentration than the equipment detection limit. For a qualitative measurement, X-ray diffraction (XRD; X-ray powder diffractogram) was used to characterize the biopolymeric concrete. The optimum waste content percentage with appropriate biopolymer concrete mixture ratio was identified for its possible commercial use. Implications: The selenium waste from a glass manufacturer initiated this study. Biopolymer-modified concrete system is of importance in encapsulating hazardous wastes, which is unique, unlike the conventional waste solidification method.

Drug-Loaded Pectin Microparticles Prepared by Emulsion-Solvent Evaporation

The aim of this study was to develop the pectin-based microparticles by emulsion-solvent evaporation technique. The effects of concentration and type of pectin and addition of glutaraldehyde on size, size distribution, drug crystalline state and drug dissolution from microparticles were investigated. The results showed that a model drug, indomethacin, could be encapsulated in microparticles. Higher molecular weight of pectin caused a larger in size of microparticles than the lower one. A high degree of esterification is preferred to stabilize the pectin microparticles. The powder x-ray diffractograms showed that all microparticles led to amorphous products while their physical mixture still showed the crystalline state of drug. Drug dissolution from the microparticles containing indomethacin and pectin was increased, resulting from the formation of an amorphous solid dispersion. Addition of glutaraldehyde, however, resulted in slower drug dissolution, compared to the formulations without glutaraldehyde or drug alone.

New Insights into an Old Molecule: Interaction Energies of Theophylline Crystal Forms

The asthma therapeutic theophylline exists in at least three anhydrous polymorphs and a monohydrate. The single-crystal X-ray structure of the high-temperature polymorph form I is presented for the first time, and the energetic relationship between forms I and II is investigated using the partial charges and chemical hardness analysis (PACHA) algorithm. It is shown that the interactions in the form I crystal network are stronger, especially the hydrogen bond. The single-crystal neutron structure of the monohydrate demonstrates static disorder of the water molecule as well as dynamic disorder of the methyl groups. PACHA investigations based on the neutron coordinates reveal that the homomeric interactions in this form are stronger than the interaction of the water with the host molecules. The dehydration of the hydrate should thus leave the theophylline network intact, explaining the isomorphic powder X-ray diffractograms of the monohydrate and its dehydrated form III.

Hierarchical 3D NiO–CdS heteroarchitecture for efficient visible light photocatalytic hydrogen generation

A novel hierarchical three dimensional (3D) NiO–CdS heteroarchitecture was successfully synthesized by a facile single pot hydrothermal route and characterized by powder X-ray diffractogram, UV-Vis spectroscopy, BET, FE-SEM and TEM. FE-SEM and TEM analyses revealed the formation of the hierarchical 3D structure of the as-prepared NiO–CdS. The purity and crystalline phase of the individual component in 3D NiO–CdS were determined by a powder X-ray diffractogram. The hierarchical 3D NiO–CdS exhibited enhanced photocatalytic activity for hydrogen generation by water reduction with an AQY value of 6%. In 3D NiO–CdS, the high hydrogen production rate in comparison to 1D CdS NWs (AQY 2%) is mainly attributed to the enhanced specific surface area and facile charge transfer from the conduction band of highly crystalline CdS to the conduction band of NiO, which reduces the recombination rate of reductive electrons and oxidative holes for efficient hydrogen production.

The effect of microwave-assisted synthesis on the physico-chemical properties of pamoate-intercalated layered double hydroxide

Layered organic-inorganic hybrid nanocomposite was prepared by inserting the pamoate anion (PA) between Zn and Al layered double hydroxide (LDH) using co-precipitation method. The ageing process was done by two different methods; conventional oil bath and microwave-assisted method at various ageing times, from 15 to 60 min. As a result of successful intercalation of PA anion into Zn–Al LDH lamella, the expansion of the interlayer spacing from 8.9 to 18.1 A was observed in the powder X-ray diffractogram of the (ZAP) nanocomposite. Percentage of PA intercalated between the LDH was higher in the nanocomposite material aged using microwave irradiation (ZAPM) compared to conventional oil bath method (ZAP). The BET surface areas of ZAPM15 and ZAPM30 were in the range of 100–106 m2/g, which were higher compared to ZAP, 90 m2/g. In general, the microwave-assisted method has improved the physico-chemical properties of the nanocomposite material with shorter ageing time of 30 min compared to 18 h ageing time by con...

Micro- and nanocrystals of the iron(iii) spin-transition material [FeIII(3-MeO-SalEen)2]PF6

The elaboration of micro- and nanometric particles of [FeIII(3-MeO-SalEen)2]PF6 (H-3-MeO-SalEen being the condensation product of 3-methoxy-substituted salicylaldehyde and N-ethylethylenediamine), a spin-transition compound of molecular nature, is reported. A sudden precipitation approach, using butan-1-ol as an anti-solvent, has been shown to produce objects, whose size and shape can be modulated by varying the selected experimental parameters (temperature, solvent, and polymeric confining agent). They are in the form of either needle-shaped (7500 × 640 × 215 (a); 3500 × 350 × 125 (b); 950 × 270 × 35 nm3 (c)) or spherical particles (18 ± 3 nm (d)). The chemical nature of these molecular materials has been confirmed by Energy-dispersive X-ray and Raman spectroscopies. The room temperature powder X-ray diffractograms indicate the formation of size-reduced particles (a–d) of crystalline character, which correspond to the unperturbed phase previously reported by Hendrickson and co-workers. Magnetic, EPR and Raman investigations demonstrate the occurrence of a low-spin ↔ high-spin transition. In agreement with the literature, disappearance of the small hysteresis and decrease of the cooperative character indicate weaker interactions within size-reduced particles. Two striking features: (i) the small shift in the transition temperatures from 162 K (bulk) to 153 K (18 nm) and (ii) the very quantitative spin transformation (fraction of high-spin residues ≤5%) contrast to those usually reported for coordination networks and point towards specificity of molecular nanomaterials.

Doxycycline and hydroxypropyl- β-cyclodextrin complex in poloxamer thermal sensitive hydrogel for ophthalmic delivery

The present study aimed to prepare a chemically and physically stable formulation of doxycycline (Doxy) in an in situ thermally sensitive hydrogel for ophthalmic delivery. An inclusion complex of Doxy and hydroxypropyl- β-cyclodextrin (HP- β-CD) was first developed to increase the stability of Doxy in aqueous solution. The physical characteristics (phase solubility profiles, thermal analysis, X-ray powder diffractograms and infrared spectra) of the Doxy-HP- β-CD inclusion complex indicated the formation of a stable 1:1 complex. Poloxamers P407 (16–22%) and P188 (0–5%) were mixed to obtain a hydrogel with an appropriate gelation temperature for opthalmic use. Formulation of the inclusion complex in the poloxamer hydrogel exhibited a suitable gelation temperature (33.3 °C) after dilution with simulated tear fluid (Gel:STF=40:7, v/v). The release of Doxy from the poloxamer hydrogel followed a zero order equation suggesting it occurs through corrosion of the poloxamer hydrogel. Stability studies demonstrated that the inclusion of Doxy by HP- β-CD markedly improved its stability in aqueous solution both at 8 and 40 °C. This formulation of a doxycycline-HP- β-CD inclusion complex in an in situ thermally sensitive poloxamer hydrogel represents a potentially effective ophthalmic Doxy delivery system.

Physicochemical Characterization and Water Vapor Sorption of Organic Solution Advanced Spray-Dried Inhalable Trehalose Microparticles and Nanoparticles for Targeted Dry Powder Pulmonary Inhalation Delivery

Novel advanced spray-dried inhalable trehalose microparticulate/nanoparticulate powders with low water content were successfully produced by organic solution advanced spray drying from dilute solution under various spray-drying conditions. Laser diffraction was used to determine the volumetric particle size and size distribution. Particle morphology and surface morphology was imaged and examined by scanning electron microscopy. Hot-stage microscopy was used to visualize the presence/absence of birefringency before and following particle engineering design pharmaceutical processing, as well as phase transition behavior upon heating. Water content in the solid state was quantified by Karl Fisher (KF) coulometric titration. Solid-state phase transitions and degree of molecular order were examined by differential scanning calorimetry (DSC) and powder X-ray diffraction, respectively. Scanning electron microscopy showed a correlation between particle morphology, surface morphology, and spray drying pump rate. All advanced spray-dried microparticulate/nanoparticulate trehalose powders were in the respirable size range and exhibited a unimodal distribution. All spray-dried powders had very low water content, as quantified by KF. The absence of crystallinity in spray-dried particles was reflected in the powder X-ray diffractograms and confirmed by thermal analysis. DSC thermal analysis indicated that the novel advanced spray-dried inhalable trehalose microparticles and nanoparticles exhibited a clear glass transition (T(g)). This is consistent with the formation of the amorphous glassy state. Spray-dried amorphous glassy trehalose inhalable microparticles and nanoparticles exhibited vapor-induced (lyotropic) phase transitions with varying levels of relative humidity as measured by gravimetric vapor sorption at 25°C and 37°C.