Jian-Ming Gu

Febuxostat methanol solvate.

In the title compound {systematic name: [2-(3-cyano-4-isobutyloxyphenyl)-4-methyl-1,3-thiazole-5-carboxylic acid (febuxostat) methanol monosolvate}, C16H16N2O3S·CH4O, the benzene and thiazole rings in the febuxostat molecule are twisted at 5.3 (1)°. In the crystal structure, intermolecular O—H⋯O and O—H⋯N hydrogen bonds link the febuxostat and methanol molecules into helical chains along the 21 screw axis.

Diamminebis[dimethylglyoximato(1–)]cobalt(III) Fluoborate and Perchlorate

One of the title complexes, trans-diamminebis[2,3-butanedione dioximato(1-)]cobalt(III) tetrafluoroborate, [Co(C 4 H 7 N 2 O 2 ) 2 (NH 3 ) 2 ]BF 4 , is isomorphous with the other, trans-diamminebis[ 2,3-butanedione dioximato-(1-)]cobalt(III) perchlorate, [Co(C 4 H 7 N 2 O 2 ) 2 (NH 3 ) 2 ]- ClO 4 . The octahedral coordination complex has an axial Co-N(NH 3 ) bond of 1.953(2) (BF 4 - salt) or 1.954 (3) A (ClO 4 - salt).

Crystal structures of vortioxetine and its methanol monosolvate

Vortioxetine, a new drug used to treat patients with major depressive disorder, has been crystallized as the free base and its methanol monosolvate. In both structures, the vortioxetine molecules have similar conformations.

Memanti­nium chloride 0.1-hydrate

The crystal structure of the title compound, C12H22N+·Cl−·0.1H2O, consists of (3,5-dimethyl-1-adamantyl)ammonium chloride (memantinium chloride) and uncoordinated water molecules. The four six-membered rings of the memantinium cation assume typical chair conformations. The Cl− counter-anion links with the memantinium cation via N—H⋯Cl hydrogen bonding, forming channels where the disordered crystal water molecules are located. The O atom of the water molecule is located on a threefold rotation axis, its two H atoms symmetrically distributed over six sites; the water molecule links with the Cl− anions via O—H⋯Cl hydrogen bonding.

Determination of minor quantities of linezolid polymorphs in a drug substance and tablet formulation by powder X-ray diffraction technique – ADDENDUM

Linezolid (LZD) is one of the first commercially available synthetic oxazolidinone antibiotics and is widely used for the treatment of multidrug-resistant Gram-positive bacterial infection. LZD was found to have five polymorphic forms. The most stable and commercialized polymorphs are known as forms II and IV. Trace content of form II in LZD form IV will cause to transition LZD form IV to II rapidly. Powder X-ray diffraction (PXRD) methods were evaluated for the determination of the polymorphic content of the drug substance and drug product. The estimated limit of detection values of the single peak method for LZD polymorph form II in drug substance and tablet formulation were 0.4 and 0.6%, respectively, while the limit of detection value of Rietveld Refinement (full-profile fitting) evaluated LZD polymorph form II in drug substance was 0.2%. The results clearly show that levels

Structures and physicochemical properties of vortioxetine salts

In the present work, novel salts of the multimodal antidepressant drug vortioxetine (VT) were crystallized with pharmaceutically acceptable acids, aiming to improve the solubility of VT. The acids for VT were selected based on ΔpKa being greater than 2 or 3. Salts of hydrobromic acid (HBr), hydrochloric acid (HCl), p-hydroxybenzoic acid (PHBA), saccharin (SAC) and L-aspartic acid (ASP) were reported. All salts were characterized by single-crystal X-ray diffraction, FT-IR, powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC). The acidic proton is transferred to the secondary N atom on the piperazine ring of VT, forming the charge-assisted hydrogen bond N+-H...X- (X = Cl, Br, O). Solubility and intrinsic dissolution rate (IDR) experiments were carried out in distilled water (pH = 7.0) to compare the solubilities of the salts with that of VT. The VT-ASP-H2O (1:1:2) salt showed 414 times higher solubility and 1722 times faster IDR compared with VT. VT-ASP-H2O (1:1:2) is a high solubility salt that is stable in a slurry experiment at 298 K in 95% ethanol. The experimental data for the VT-ASP-H2O (1:1:2) salt identify it as a promising drug candidate.

Crystal structure of febuxostat–acetic acid (1/1)

The asymmetric unit of the title compound [systematic name: 2-(3-cyano-4-isobutyloxyphenyl)-4-methylthiazole-5-carboxylic acid–acetic acid (1/1)], C16H16N2O3S·CH3COOH, contains a febuxostat molecule and an acetic acid molecule. In the febuxostat molecule, the thiazole ring is nearly coplanar with the benzene ring [dihedral angle = 3.24 (2)°]. In the crystal, the febuxostat and acetic acid molecules are linked by O—H⋯O, O—H⋯N hydrogen bonds and weak C—H⋯O hydrogen bonds, forming supramolecular chains propagating along the b-axis direction. π–π stacking is observed between nearly parallel thiazole and benzene rings of adjacent molecules; the centroid-to-centroid distances are 3.8064 (17) and 3.9296 (17) Å.

Moxifloxacinium chloride monohydrate

The title compound {systematic name: 7-[(1S,6S)-8-aza-2-azoniabicyclo[4.3.0]non-8-yl]-1-cyclopropyl-6-fluoro-8-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylic acid chloride monohydrate}, C21H25FN3O4 +·Cl−·H2O, crystallizes with two moxifloxacinium cations, two chloride ions and two uncoordinated water molecules in the unit cell. The crystal structure has a pseudo-inversion center except for the chloride ions. In both moxifloxacinium cations, the quinoline rings are approximately planar, the maximum atomic deviations being 0.107 (3) and 0.118 (3) Å. The piperidine rings adopt a chair conformation while the pyrrolidine rings display a half-chair conformation. In the crystal, the carboxyl groups, the protonated piperidyl groups, the uncoordinated water molecule and chloride anions participate in O—H⋯O, O—H⋯Cl and N—H⋯Cl hydrogen bonding; weak intermolecular C—H⋯O and C—H⋯Cl hydrogen bonding is also present in the crystal structure.

Triamcinolone acetonide acetate

In the crystal structure of the title compound [systematic name: 2-(4b-fluoro-5-hydroxy-4a,6a,8,8-tetramethyl-2-oxo-2,4a,4b,5,6,6a,9a,10,10a,10b,11,12-dodecahydro-7,9-dioxapentaleno[2,1-a]phenanthren-6b-yl)-2-oxoethyl acetate], C26H33FO7, the molecules are connected by intermolecular O—H⋯O hydrogen bonds into an infinite supramolecular chain along the b axis. The molecular framework consists of five condensed rings, including three six-membered rings and two five-membered rings. The cyclohexa-2,5-dienone ring is nearly planar [maximum deviation = 0.013 (3) Å], while the cyclohexane rings adopt chair conformations. The two five-membered rings, viz. cyclopentane and 1,3-dioxolane, display envelope conformations.

[1-(Di­phenyl­phosphinoyl)­propa-1,2-dienyl]­benzene

The title compound, C21H17OP, is a rare example of a structurally characterized allenyl phosphine oxide. The allenyl moiety is linear, as expected, with a bond angle of 179.2 (3)° at the central C atom.