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Physical stability and consistent dose delivery of pharmaceutical suspension formulations comprised of microcrystalline cellulose (MCC) and sodium carboxymethylcellulose (NaCMC) hydrogels is dependent on their rheological properties. To obtain the desired rheological characteristics, good control of the hydrogel dispersion in water is required. The goal of this study was to evaluate whether the XL7-100 Process Viscometer could be employed as a process analytical technology (PAT) tool to monitor the dispersion process in real time during batch manufacturing. Using this instrument, viscosity profiles were measured during the hydrogel processing for a range of operating conditions. It was confirmed that viscosity obtained by the XL7-100 Process Viscometer in the off-line mode, could be linearly correlated to that of the conventional Brookfield viscometer. In addition, the XL7-100 Process Viscometer was able to detect variations in the hydrogel concentrations as well as process conditions in real time. Under fixed operating conditions, the dynamic viscosity profile showed low variability and good inter-batch reproducibility for a properly dispersed hydrogel. For a well-validated mixing process, an off-trend in-line viscosity reading may be indicative of batch failure or poor dispersion homogeneity. Therefore, the in-line viscometer can be used in manufacturing to monitor the batch to batch consistency. However, it is not proven to be able to characterize the real-time structure formation of the hydrogel. It is recommended that the in-line viscometer be used as a complimentary tool along with the off-line rheometer for both efficient and effective in-process quality control of the MCC & NaCMC hydrogel dispersion. [ABSTRACT FROM AUTHOR]

Ferrihydrite (Fe5O7(OH)·4H2O) is poorly crystalline hydrated ferric oxyhydroxide. Using a treatment in a mixed FeCl2/NaOH solution, we attempted to prepare magnetic nanoscale particles from ferrihydrite. During the treatment, the concentration of FeCl2was fixed at 0.1 M, and the concentration of NaOH was varied from 0.09 to 0.26 M. The as-prepared products were characterized using X-ray diffraction, transmission electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and vibrating sample magnetometry. The experimental results showed that under the FeCl2/NaOH solution treatment, the ferrihydrite transformed into nanoscale γ-Fe2O3via an α-FeO(OH) intermediate phase. The as-prepared products contained rod-type α-FeO(OH), sphere-type γ-Fe2O3,and flake-type γ-Fe2O3particles. A mechanism for a coupling of the aggregation and the transition was proposed to interpret the formation of highly crystalline nanoscale particles from the poorly crystalline smaller particles. [ABSTRACT FROM AUTHOR]

[Co2(TTBT)4(1,2-BDC)2] n  · 4nH2O (1), [Pb2(TTBT)2(1,3-BDC)2] n  · nTTBT · 2nH2O (2), [Fe(TTBT)(1,4-BDC)(H2O)] n (3), and [Zn(TTBT)(1,4-BDC)(H2O)] n (4) have been hydrothermally synthesized by self-assembly of TTBT (TTBT = 10,11,12,13-tetrahydro-4,5,9,14-tetraaza-benzo[b]triphenylene), benzene-dicarboxylic acid ligands 1,2-H2BDC, 1,3-H2BDC or 1,4-H2BDC (1,2-H2BDC = 1,2-benzenedicarboxylic acid, 1,3-H2BDC = 1,3-benzenedicarboxylic acid, 1,4-H2BDC = 1,4-benzenedicarboxylic acid), and various metal salts. Compound 1 has dinuclear cluster units, four dimeric Co2 units connected to form a 32-membered ring via weak offset π–π interactions, which are further stacked via strong π–π interactions to form a 3-D supramolecular framework. Complex 2 contains 2-D layers with rhombohedral grids, which are connected to a 3-D structure by π–π interactions. 3 and 4 feature 1-D infinite chains, which are further extended by strong π–π interactions and O–H···O hydrogen bonds resulting in 3-D supramolecular architectures. The photoluminescent properties of 2 and 4 have also been investigated. [ABSTRACT FROM AUTHOR]

Three 1-D reduced molybdenum(V) phosphates, [Ni(OH)2][Na2(H2O)3]2{Ni[(MoO2)6(OH)3(HPO4)3(PO4)]2} · 2C6H14N2 · 2H3O · 5H2O (1), [Ni(H2O)2][K(H2O)5]2{Ni[(MoO2)6(OH)3(HPO4)3(PO4)]2} · 2C6H14N2 · 2H3O · 4H2O (2), and [Cu(H2O)2][Na(H2O)5]2{Cu[(MoO2)6(OH)3(HPO4)3(PO4)]2} · 2C6H14N2 · 2H3O · 4H2O (3), have been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. The crystallographic analysis reveals that 1 is based on {Ni[Mo6O12(OH)3(HPO4)3(PO4)]2} clusters connected through {[Ni(OH)2][Na2(H2O)3]2} pentanuclear mixed-metal cluster units to yield unusual 1-D chains along the c-axis, which further form 3-D supramolecular networks via hydrogen-bonding. Compounds 2 and 3 are heterogeneous isostructural compounds. Both are built from M[Mo6P4]2 (M = Ni or Cu) blocks as the structural motif combined with [MO4(H2O)2] (M = Ni or Cu) octahedra to form 1-D chains, where M[Mo6P4]2 (M = Ni or Cu) is bonded by [M′(H2O)5] (M′ = K or Na). Furthermore, bulk carbon paste electrode modified with 1 (1-CPE) displays good electrocatalytic activity toward reduction of nitrite or bromate. [ABSTRACT FROM PUBLISHER]

A new Zn(II) phosphonate, (NH4)[Zn(HPMIDA)(H2O)2] (1) (H4PMIDA = N-(phosphonomethyl)iminodiacetic acid), has been solvothermally synthesized and characterized by elemental analysis, IR, TGA fluorescence, and X-ray single-crystal diffraction. Compound 1 is an example of a six-coordinate Zn-carboxylate-phosphonate and possesses a 3-D supramolecular structure built from mononuclear anions [image omitted] through hydrogen bonding. Compound 1 exhibits a solid-state fluorescent emission band at 593 nm under excitation of 413 nm. [ABSTRACT FROM AUTHOR]

Synthesis, characterization, crystal structure, and biological studies of two complexes with glycolic acid are described. The solid complexes were formulated as K2[VO(C2H2O3)(C2H3O3)2] · H2O (1) and K2[{VO2(C2H2O3)}2] (2) and characterized by X-ray studies, Fourier transform infrared spectroscopy (FTIR), Electron paramagnetic resonance (EPR), and magnetic susceptibility. Conversion of 1 to 2 was studied in aqueous solution by UV-Vis spectroscopy and in the solid state by diffuse reflectance spectroscopy. Complex 2 contains dinuclear [{VO2(C2H2O3)}2]2- anions in which glycolate(2-) is a five-membered chelating ring formed by carboxylate and α-hydroxy groups. The geometry around the vanadium in 2 was interpreted as intermediate between a trigonal bipyramid and a square pyramid. Vanadium(IV) is pentacoordinate in 1 as a distorted square pyramid. Complex 1 contains a vanadyl group (V=O) surrounded by two oxygens from deprotonated carboxylate and hydroxy groups forming a five-membered ring. Two oxygens from different glycolates(1-) are bonded to the (V=O) also. Biological analysis for potential cytotoxic effects of 1 was performed using Human Cervix Adenocarcinoma (HeLa) cells, a human cervix adenocarcinoma-derived cell line. After incubation for 48 h, 1 causes 90 and 95% of HeLa cells death at 20 and 200 μmol L-1, respectively. [ABSTRACT FROM AUTHOR]