A distribution curve for the systems ZnSCo1-xS, ZnSFe1-x and ZnSMnS is established by precipitation at 25°C and pH 5 with a deficient quantity of Na2S in mixed ZnSO4CoSO4, ZnSO4FeSO4, and ZnSO4MnSO4. solutions. The distribution reaction between the solid and liquid phase leads to the formation of mixed sulphides. The saturation limits for the different solid solutions can be derived from the slope changes in the respective distribution curves.

Mixed K-Me zippeite-group phases (Me = Mn, Co, Ni, Zn) have been synthesized by adjusting a UO2SO4 solution containing MeSO4 to a pH of 3.8 by means of KOH. The solution was kept for 75 hours at 150 degrees C and an approximate pressure of 3.5 MPa. Single-crystal X-ray studies, chemical analysis and bond-valence calculations revealed the composition K0.5Me0.75[(UO2)(2)SO4O2]center dot 3H(2)O. The crystals are monoclinic, space group C2/c. For Me = Mn, we found a 8.661(6), b 14.375(8), c 17.705(12) angstrom, beta 104.12(5)degrees; for Me = Co, the cell parameters are a 8.651(5), b 14.188(8), c 17.713(13) angstrom, beta 104.14(6)degrees, for Me = Ni, they are a 8.662(5), b 14.095(8), c 17.770(9) angstrom, beta 104.18(5)degrees, and for Me = Zn, they are a 8.650(6), b 14.180(12), c 17.709(13) angstrom, beta 104.14(6)degrees. The structures were refined to unweighted residuals of 0.0525, 0.0459, 0.0383 and 0.0690, respectively The structures possess a layer structure parallel to (0 10) comparable to that of zippeite. We demonstrate that a zippeite-group phase with all interlayer containing monovalent potassium cation and divalent transition metal cations call be synthesized. The interlayer contains two symmetrically distinct Me atoms, one K atom and H2O molecules. Both Me atoms (Me1 Me2) are coordinated by six oxygen atoms forming distorted octahedra. In the Me1 octahedron, two O atoms are part of (UO2)(2+) of adjacent uranyl oxo sulfate layers, and four are part of four H2O molecules of the interlayer, which is the same configuration as found in the crystal structure of zinc-zippeite, cobalt-zippeite and magnesium-zippeite. In the Me2 octahedron, four O atoms are part of (UO2)(2+) of the adjacent Uranyl oxo sulfate layers, and two O atoms are part of two equivalent positions of a H2O group.

Ranitidine hydrochloride (RAN-HCl), a known anti-ulcer drug, is the product of reaction between HCl and ranitidine base (RAN-B). RAN-HCl has been extensively studied; however this is not the case of the RAN-B. The solid state characterization of RAN-B polymorphs has been carried out using different analytical techniques (microscopy, thermal analysis, Fourier transform infrared spectrometry in the attenuated total reflection mode, (13)C-CPMAS-NMR spectroscopy and X-ray powder diffraction). The crystal structures of RAN-B form I and form II have been determined using conventional X-ray powder diffraction in combination with simulated annealing and whole profile pattern matching, and refined using rigid-body Rietveld refinement. RAN-B form I is a monoclinic polymorph with cell parameters: a = 7.317(2), b = 9.021(2), c = 25.098(6) A, beta = 95.690(1) degrees and space group P2(1)/c. The form II is orthorhombic: a = 31.252(4), b = 13.052(2), c = 8.0892(11) A with space group Pbca. In RAN-B polymorphs, the nitro group is involved in a strong intramolecular hydrogen bond responsible for the existence of a Z configuration in the enamine portion of the molecules. A tail to tail packing motif can be denoted via intermolecular hydrogen bonds. The crystal structures of RAN-B forms are compared to those of RAN-HCl polymorphs. RAN-B polymorphs are monotropic polymorphic pairs.

A new polymorphic form of Alprazolam (Xanax), 8-chloro-1-methyl-6-phenyl-4H-[1,2,4]triazolo-[4,3-alpha][1,4]benzodiazepine, C(17)H(13)ClN(4), has been investigated by means of X-ray powder diffraction (XRPD), single crystal X-ray diffraction, and differential scanning calorimetry (DSC). This polymorphic form (form III) was obtained during DSC experiments after the exothermic recrystallization of the melt of form I. The crystal unit cell dimensions for form III were determined from diffractometer methods. The monoclinic unit cell found for this polymorph using XRPD after indexing the powder diffractogram was confirmed by the cell parameters obtained from single crystal X-ray diffractometry on a crystal isolated from the DSC pans. The single crystal unit cell parameters are: a = 28.929(9), b = 13.844(8), c = 7.361(3) angstroms, beta = 92.82(3) degrees , V = 2944(2) angstroms(3), Z = 8, space group P2(1) (No.4), Dx = 1.393 Mg/m(3). The structure obtained from single crystal X-ray diffraction was used as initial model for Rietveld refinement on the powder diffraction data of form III. The temperature phase transformations of alprazolam were also studied using high temperature XRPD. A review of the different phases available in the Powder Diffraction File (PDF) database for this drug is described bringing some clarification and corrections.

In order to improve the dissolution and absorption properties of loviride, a poorly soluble antiviral agent, sucrose co-freeze–dried nanopowders were prepared, characterized and evaluated. Tween 80/poloxamer 188-stabilized nanosuspensions were produced on a laboratory scale using media milling. The milling process was monitored by dynamic light scattering (DLS) and resulted in particles with a mean size of 264±14nm and a distribution width of 59±6nm after 4h of milling. Co-freeze–drying of the nanosuspensions with sucrose had an inhibiting effect on nanoparticle agglomeration and yielded solid “nanopowders” that were resuspendable and homogeneous with respect to loviride content. X-ray powder diffraction (XRPD) confirmed the presence of small loviride crystallites and indicated that sucrose and poloxamer 188 were crystalline. Differential scanning calorimetry (DSC) showed melting peaks of poloxamer 188, sucrose and loviride. Time-resolved XRPD indicated that sucrose crystallization was complete within 24h of storage. Scanning electron microscopy (SEM) suggested the formation of sheet-like matrix structures. The dissolution rate of loviride from the nanopowders was excellent. A Caco-2 experiment on the nanopowder showed a significantly higher cumulative amount transported after 120min (1.59±0.02μg) compared to the physical mixture (0.93±0.01μg) and the untreated loviride (0.74±0.03μg).

In the present study the properties of binary solid dispersions made up of PVP VA64, Myrj 52 and indomethacin (IMC) are studied and characterized. The solid dispersions were prepared by dissolving the materials in dichloromethane, followed by solvent evaporation under reduced pressure at 55 degrees C in a rotavapor. Binary solid dispersions were characterized by standard and modulated temperature differential scanning calorimetry (MTDSC), thermogravimetry (TGA) and X-ray powder diffraction (XRPD). XRPD analysis showed that the initial IMC was in its gamma-form, and that it was transformed to the beta-form (reported to be a solvate) together with an amorphous fraction in the solid dispersions. A mixture of the beta-form and amorphous IMC was also obtained in the binary systems containing less than 30% polymer. IMC without adding polymer was subjected to the same experimental procedures as in the solid dispersions, and used as a model to characterize the solid-state transformations. The following order of transitions was observed: from the initial gamma-form, the beta-form was obtained together with an amorphous component, then the crystalline beta-form transforms into the alpha-form which melts and recrystallizes into the most stable gamma-form.

In the title compound [alternative name: (2,2,6R-trimethyltetrahydrofuro[2R, 3R-d][1,3]dioxol-5S-yl) methyl 4-methylbenzenesulfonate], C16H22O6S, the ribo-pentofuranose ring is in the T (twisted) conformation, with atom C3 exo and atom C4 endo. The isopropylidene ring is in an envelope conformation. The crystal structure is stabilized by means of van der Waals interactions and weak C-H center dot center dot center dot O interactions.

In the title compound [alternative name: (2,2,6 R -trimethyltetrahydrofuro[2 R ,3 R - d ][1,3]dioxol-5 S -yl)methyl 4-methylbenzenesulfonate], C 16 H 22 O 6 S, the ribo -pentofuranose ring is in the T (twisted) conformation, with atom C3 exo and atom C4 endo . The isopropylidene ring is in an envelope conformation. The crystal structure is stabilized by means of van der Waals interactions and weak C—H...O interactions.

In the title compound, C 11 H 13 NO 3 , the methoxy­carbonyl group is rotated out of the plane of the 4-methoxy­benzyl group. The conformation found in the crystal structure differs from that computed in vacuo , where the two groups are coplanar. The crystal structure is stabilized by van der Waals inter­actions and weak inter­actions of the C—H⋯O type.

In the title compound, C(6)H(8)N(2)O(2)S, also known as N-acetyl-2-thiohydantoin-alanine, the molecules are joined by N-H...O hydrogen bonds, forming centrosymmetric R2(2)(8) dimers; these dimers are linked by C-H...O interactions to form R2(2)(10) rings, thus forming C2(2)(10) chains that run along the [101] direction.

In the title compound, C 11 H 13 NO 3 , the methoxycarbonyl group is rotated out of the plane of the 4-methoxybenzyl group. The conformation found in the crystal structure differs from that computed in vacuo , where the two groups are coplanar. The crystal structure is stabilized by van der Waals interactions and weak interactions of the C—H...O type.

In the title compound, C 6 H 8 N 2 O 2 S, also known as N -acetyl-2-thiohydantoin–alanine, the molecules are joined by N—H...O hydrogen bonds, forming centrosymmetric R 2 2 (8) dimers; these dimers are linked by C—H...O interactions to form R 2 2 (10) rings, thus forming C 2 2 (10) chains that run along the [101] direction.

The crystal structure of carnidazole form II, O-methyl [2-(2-methyl-5-nitro-1H-imidazole-1-yl)ethyl]thiocarbamate, has been determined using synchrotron X-ray powder diffraction in combination with simulated annealing and whole profile pattern matching, and refined by the Rietveld method. For structure solution, 12 degrees of freedom were defined: one motion group and six torsions. Form II crystallizes in space group P2(1)/n, Z=4, with unit cell parameters after Rietveld refinement: a=13.915(4), b=8.095(2), c=10.649(3) A, beta=110.83(1) degrees, and V=1121.1(5) A3. The two polymorphic forms, as well as the hydrate, crystallize in the monoclinic space group P2(1)/n having four molecules in the cell. In form II, the molecules are held together by forming two infinite zig-zag chains via hydrogen bonds of the type N--H...N, the same pattern as in form I. A conformational study of carnidazole, at semiempirical PM3 level, was performed using stochastic approaches based on modification of the flexible torsion angles. The values of the torsion angles for the molecules of the two polymorphic forms and the hydrate of carnidazole are compared to those obtained from the conformational search. Form I and form II are enantiotropic polymorphic pairs this agrees with the fact that the two forms are conformational polymorphs.

The indexed powder diffraction pattern and related crystallographic data for polymorphic form 2 of carnidazole (C8H12N4O3S) are reported, as a first step in the structure determination by powder diffraction methods. The unit cell dimensions were determined from high resolution synchrotron powder diffraction data (λ=0.079 998 0 nm) and evaluated by indexing programs. The monoclinic cell found for this polymorph isa=1.3908(2) nm,b=08094(2) nm,c=1.0645(2) nm,β=110.82(2)°,V=1.12015(27)nm3,Z=4,Dx=1.445 Mg∕m3.

Solid dispersions made up of itraconazole and Inutec SP1, a new polymeric surfactant, were prepared by spray drying and hot-stage extrusion. Differential scanning calorimetry (DSC) and X-ray powder diffraction (XRD) were used to evaluate the miscibility of the components of the dispersions, and dissolution experiments were performed in simulated gastric fluid without pepsin (SGFsp) to evaluate the pharmaceutical performance of itraconazole from the solid dispersions. DSC analysis showed that the solid dispersions are phase separated systems made up of glassy and crystalline itraconazole and amorphous Inutec SP1. The amount of crystalline drug substance was higher in the dispersions prepared by hot-stage extrusion and was clearly a function of the drug concentration. Since no crystallinity could be detected by XRD points to the fact that the crystallites formed are very small in size. Despite the presence of glassy and crystalline clusters, the dissolution properties of the solid dispersions were significantly improved in comparison to pure itraconazole (glassy or crystalline) or physical mixtures with Inutec SP1. This study proves the potential of the new polymeric surfactant as a carrier in the formulation of solid dispersions for poorly soluble drugs.

A new series of 1,4-dihydropyridines (1,4-DHPs) bearing a semicarbazone moiety on C5 (8a-g) have been synthesized from suitably functionalized 1,4-DHPs (2) and semicarbazide. Compounds (8a-g) did not cyclize to the respective seven member ring though this is a favoured 7-endo-trig process. Geometrical and structural features determined by theoretical, DFT (B3LYP/6-31G*) and experimental (X-Ray diffraction) data, reveal the presence of a low energy stereoisomer, namely (E) s-trans, which is also present in solution according to NOe experiments carried out on compound (8a). These geometrical findings account for the lack of cyclization of compounds (8a-g), and reveal that they meet the structural requirements needed for biological activity as calcium-channel modulators.

Unprecedented 2-iminium chloride salts of 5,8-dihydro-2H-pyrido[3,2-e][1,3]thiazines derivatives (8) were easily synthesized in one step from the corresponding o-chloroformyl-1,4-dihydropyridine (2) and thiourea. The structural study has been carried out by X-ray crystallography and theoretical calculations at the B3LYP/6-31G* levels and reveal that the new salts exhibit appropriate structural features to behave as calcium channel modulators.