scholarly journals Acemetacin cocrystals and salts: structure solution from powder X-ray data and form selection of the piperazine salt

IUCrJ ◽  
2014 ◽  
Vol 1 (2) ◽  
pp. 136-150 ◽  
Author(s):  
Palash Sanphui ◽  
Geetha Bolla ◽  
Ashwini Nangia ◽  
Vladimir Chernyshev

Acemetacin (ACM) is a non-steroidal anti-inflammatory drug (NSAID), which causes reduced gastric damage compared with indomethacin. However, acemetacin has a tendency to form a less soluble hydrate in the aqueous medium. We noted difficulties in the preparation of cocrystals and salts of acemetacin by mechanochemical methods, because this drug tends to form a hydrate during any kind of solution-based processing. With the objective to discover a solid form of acemetacin that is stable in the aqueous medium, binary adducts were prepared by the melt method to avoid hydration. The coformers/salt formers reported are pyridine carboxamides [nicotinamide (NAM), isonicotinamide (INA), and picolinamide (PAM)], caprolactam (CPR),p-aminobenzoic acid (PABA), and piperazine (PPZ). The structures of an ACM–INA cocrystal and a binary adduct ACM–PABA were solved using single-crystal X-ray diffraction. Other ACM cocrystals, ACM–PAM and ACM–CPR, and the piperazine salt ACM–PPZ were solved from high-resolution powder X-ray diffraction data. The ACM–INA cocrystal is sustained by the acid...pyridine heterosynthon and N—H...O catemer hydrogen bonds involving the amide group. The acid...amide heterosynthon is present in the ACM–PAM cocrystal, while ACM–CPR contains carboxamide dimers of caprolactam along with acid–carbonyl (ACM) hydrogen bonds. The cocrystals ACM–INA, ACM–PAM and ACM–CPR are three-dimensional isostructural. The carboxyl...carboxyl synthon in ACM–PABA posed difficulty in assigning the position of the H atom, which may indicate proton disorder. In terms of stability, the salts were found to be relatively stable in pH 7 buffer medium over 24 h, but the cocrystals dissociated to give ACM hydrate during the same time period. The ACM–PPZ salt and ACM–nicotinamide cocrystal dissolve five times faster than the stable hydrate form, whereas the ACM–PABA adduct has 2.5 times faster dissolution rate. The pharmaceutically acceptable piperazine salt of acemetacin exhibits superior stability, faster dissolution rate and is able to overcome the hydration tendency of the reference drug.

2020 ◽  
Vol 76 (11) ◽  
pp. 1024-1033
Author(s):  
Fang-Hua Zhao ◽  
Shi-Yao Li ◽  
Wen-Yu Guo ◽  
Zi-Hao Zhao ◽  
Xiao-Wen Guo ◽  
...  

Two new CdII MOFs, namely, two-dimensional (2D) poly[[[μ2-1,4-bis(1H-benzimidazol-1-yl)butane](μ2-heptanedioato)cadmium(II)] tetrahydrate], {[Cd(C7H10O4)(C18H18N4)]·4H2O} n or {[Cd(Pim)(bbimb)]·4H2O} n (1), and 2D poly[diaqua[μ2-1,4-bis(1H-benzimidazol-1-yl)butane](μ4-decanedioato)(μ2-decanedioato)dicadmium(II)], [Cd2(C10H16O4)2(C18H18N4)(H2O)2] n or [Cd(Seb)(bbimb)0.5(H2O)] n (2), have been synthesized hydrothermally based on the 1,4-bis(1H-benzimidazol-1-yl)butane (bbimb) and pimelate (Pim2−, heptanedioate) or sebacate (Seb2−, decanedioate) ligands. Both MOFs were structurally characterized by single-crystal X-ray diffraction. In 1, the CdII centres are connected by bbimb and Pim2− ligands to generate a 2D sql layer structure with an octameric (H2O)8 water cluster. The 2D layers are further connected by O—H...O hydrogen bonds, resulting in a three-dimensional (3D) supramolecular structure. In 2, the CdII centres are coordinated by Seb2− ligands to form binuclear Cd2 units which are linked by bbimb and Seb2− ligands into a 2D hxl layer. The 2D layers are further connected by O—H...O hydrogen bonds, leading to an 8-connected 3D hex supramolecular network. IR and UV–Vis spectroscopy, thermogravimetric analysis and solid-state photoluminescence analysis were carried out on both MOFs. Luminescence sensing experiments reveal that both MOFs have good selective sensing towards Fe3+ in aqueous solution.


2014 ◽  
Vol 70 (6) ◽  
pp. 562-565 ◽  
Author(s):  
Wei Zhang ◽  
Yu-Quan Feng

A novel dinuclear bismuth(III) coordination compound, [Bi2(C7H3NO4)2(N3)2(C12H8N2)2]·4H2O, has been synthesized by an ionothermal method and characterized by elemental analysis, energy-dispersive X-ray spectroscopy, IR, X-ray photoelectron spectroscopy and single-crystal X-ray diffraction. The molecular structure consists of one centrosymmetric dinuclear neutral fragment and four water molecules. Within the dinuclear fragment, each BiIIIcentre is seven-coordinated by three O atoms and four N atoms. The coordination geometry of each BiIIIatom is distorted pentagonal–bipyramidal (BiO3N4), with one azide N atom and one bridging carboxylate O atom located in axial positions. The carboxylate O atoms and water molecules are assembledviaO—H...O hydrogen bonds, resulting in the formation of a three-dimensional supramolecular structure. Two types of π–π stacking interactions are found, with centroid-to-centroid distances of 3.461 (4) and 3.641 (4) Å.


Crystals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 536
Author(s):  
Xian-Rui Zhang ◽  
Lei Gao ◽  
Gui-Yuan He ◽  
Chao-Jie Chen

Investigation on the solid-state pharmaceutical chemistry has been known as an intriguing strategy to not only modify the physicochemical properties of drugs but also expand the solid form landscape. Vortioxetine (VOT) is an effective but poorly soluble antidepressant. To improve the solubility of vortioxetine and expand possible solid forms, in this paper, four novel solid forms of vortioxetine with dihydroxybenzoic acids (VOT-23BA, VOT-24BA-TOL, VOT-25BA, and VOT-26BA, 23BA = 2,3-dihydroxybenzoic acid, 24BA = 2,4-dihydroxybenzoic acid, 25BA = 2,5-dihydroxybenzoic acid, 26BA = 2,6-dihydroxybenzoic acid, and TOL = toluene) were synthesized first by a solvent evaporation method and then characterized by single-crystal X-ray diffraction (SCXRD), thermal, and XRD techniques. VOT-24BA-TOL, VOT-25BA, and VOT-26BA, showed similar [2+2] tetrameric R 4 4 (12) hydrogen bonds by acid-piperazine heterosynthon. In the VOT-23BA-H2O salt, the VOT cation and 23BA anion interacted through protonated piperazine-hydroxyl N-H···O hydrogen bonds, not protonated piperazine-deprotonated carboxylic acid N-H···O hydrogen bonds. Solubility studies were carried out in purified water and it was found that the VOT-23BA-H2O, VOT-25BA, and VOT-26BA salts exhibited an increase in water compared to pure VOT. The solubility of the stabilized salt formations followed the order of VOT-25BA > VOT-26BA > VOT-23BA-H2O in purified water.


2018 ◽  
Vol 74 (2) ◽  
pp. 240-247 ◽  
Author(s):  
Nassima Bendjellal ◽  
Chahrazed Trifa ◽  
Sofiane Bouacida ◽  
Chaouki Boudaren ◽  
Mhamed Boudraa ◽  
...  

In coordination chemistry and crystal engineering, many factors influence the construction of coordination polymers and the final frameworks depend greatly on the organic ligands used. The diverse coordination modes of N-donor ligands have been employed to assemble metal–organic frameworks. Carboxylic acid ligands can deprotonate completely or partially when bonding to metal ions and can also act as donors or acceptors of hydrogen bonds; they are thus good candidates for the construction of supramolecular architectures. We synthesized under reflux or hydrothermal conditions two new alkaline earth(II) complexes, namely poly[(1,10-phenanthroline-κ2N,N′)bis(μ-3-phenylprop-2-enoato-κ3O,O′:O)calcium(II)], [Ca(C10H7O2)2(C10H8N2)]n, (1), and poly[(1,10-phenanthroline-κ2N,N′)(μ3-3-phenylprop-2-enoato-κ4O:O,O′:O′)(μ-3-phenylprop-2-enoato-κ3O,O′:O)barium(II)], [Ba(C10H7O2)2(C10H8N2)]n, (2), and characterized them by FT–IR and UV–Vis spectroscopies, thermogravimetric analysis (TGA) and single-crystal X-ray diffraction analysis, as well as by powder X-ray diffraction (PXRD) analysis. Complex (1) features a chain topology of type 2,4 C4, where the Ca atoms are connected by O and N atoms, forming a distorted bicapped trigonal prismatic geometry. Complex (2) displays chains of topology type 2,3,5 C4, where the Ba atom is nine-coordinated by seven O atoms of bridging/chelating carboxylate groups from two cinnamate ligands and by two N atoms from one phenanthroline ligand, forming a distorted tricapped prismatic arrangement. Weak C—H...O hydrogen bonds and π–π stacking interactions between phenanthroline ligands are responsible to the formation of a supramolecular three-dimensional network. The thermal decompositions of (1) and (2) in the temperature range 297–1173 K revealed that they both decompose in three steps and transform to the corresponding metal oxide.


2017 ◽  
Vol 73 (4) ◽  
pp. 314-318 ◽  
Author(s):  
Xu Wei ◽  
Jian-Hua Li ◽  
Qiu-Ying Huang ◽  
Xiang-Ru Meng

The unsymmetrical N-heterocyclic ligand 1-[(benzotriazol-1-yl)methyl]-1H-1,3-imidazole (bmi) has three potential N-atom donors and can act in monodentate or bridging coordination modes in the construction of complexes. In addition, the bmi ligand can adopt different coordination conformations, resulting in complexes with different structures due to the presence of the flexible methylene spacer. Two new complexes, namely bis{1-[(benzotriazol-1-yl)methyl]-1H-1,3-imidazole-κN3}dibromidomercury(II), [HgBr2(C10H9N5)2], and bis{1-[(benzotriazol-1-yl)methyl]-1H-1,3-imidazole-κN3}diiodidomercury(II), [HgI2(C10H9N5)2], have been synthesized through the self-assembly of bmi with HgBr2or HgI2. Single-crystal X-ray diffraction shows that both complexes are mononuclear structures, in which the bmi ligands coordinate to the HgIIions in monodentate modes. In the solid state, both complexes display three-dimensional networks formed by a combination of hydrogen bonds and π–π interactions. The IR spectra and PXRD patterns of both complexes have also been recorded.


2004 ◽  
Vol 59 (6) ◽  
pp. 661-672 ◽  
Author(s):  
Virginia Lozano ◽  
Oliver Moers ◽  
Peter G. Jones ◽  
Armand Blaschette

Two crystal structures (polymorphs) of di(4-bromobenzenesulfonyl)amine (1), as determined by low-temperature single-crystal X-ray diffraction, are reported: Form A, monoclinic, P21/c, Z' = 1; form B: monoclinic, P21/c, Z' = 2. In A, the molecule adopts an extended conformation approximating to C2 symmetry, whereas the two independent molecules of form B display a folded hair-pin conformation with pseudo-mirror symmetry [torsion τ (C-S···S’-C’) and intercentroid distance dIC of the aromatic rings in A: 173.2° and 750.8 pm, in B: −5.4/−8.90° and 364.1/366.5 pm]. The packings of both polymorphs consist of layers, in which the molecules are connected by N-H···O hydrogen bonds in one and by Br···O interactions in the other dimension. The 1:1 onium salt (2; monoclinic, P21/n, Z' = 1) produced on N-deprotonation of 1 with 2,4-dimethylpyridine is structurally related to B. Its packing involves strands of formula units, whereby the anions retain the folded conformation (τ = 5.8°, dIC = 372.5 pm) and perfectly mimic the catemeric Br···O pattern of B, while the cations are isotactically connected to the anion backbone via an N-H(···O)2 three-centre bond. In all structures, a three-dimensional network of weak hydrogen bonds C-H···A (A = O, in 2 also N−) and C-H···Br contacts supports the controlling N-H···O and Br···O interactions; moreover, an intermolecular (π···π) stacking dimer of the type phenyl/phenyl and a (π···π) stacking trimer of the type phenyl/pyridinium/phenyl have been identified in A and 2, respectively. None of the structures exhibits very short bromine-bromine contacts suggestive of specific attractive forces.


2019 ◽  
Vol 19 (3) ◽  
pp. 660
Author(s):  
Yudi Wicaksono ◽  
Dwi Setyawan ◽  
Siswandono Siswandono ◽  
Tri Agus Siswoyo

Preparation and characterization of a novel cocrystal of atorvastatin calcium with succinic acid coformer were successfully performed. This research aims to modify the crystalline form of atorvastatin calcium through cocrystallization with succinic acid coformer. The cocrystal was prepared by a solvent evaporation method and characterized by Powder X-Ray Diffraction (PXRD), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The atorvastatin calcium-succinic acid cocrystal has new crystalline peaks at 2θ of 12.9, 18.2 and 26.7° indicating the formation of a new crystalline phase. The cocrystal showed the melting point at 205.7 °C with an enthalpy of fusion 30.2 J/g which is different from the initial components. The FTIR spectra of cocrystal showed the shifting of absorption peaks of groups of initial components indicating of formation of atorvastatin calcium-succinic acid cocrystal through acid–amide intermolecular hydrogen bond interactions. The solubility and dissolution test showed that the cocrystal has solubility and dissolution rate significantly higher than the solubility and dissolution rate of pure atorvastatin calcium.


2018 ◽  
Vol 74 (12) ◽  
pp. 1923-1927 ◽  
Author(s):  
K. V. Drozd ◽  
S. G. Arkhipov ◽  
E. V. Boldyreva ◽  
G. L. Perlovich

The title 1:1 salt, C7H8NO2+·C5H3N2O2−(systematic name: 4-carboxyanilinium pyrazine-2-carboxylate), was synthesized successfully by slow evaporation of a saturated solution from water–ethanol (1:1v/v) mixture and characterized by X-ray diffraction (SCXRD, PXRD) and calorimetry (DSC). The crystal structure of the salt was solved and refined at 150 and 293 K. The salt crystallizes with one molecule of 4-aminobenzoic acid (PABA) and one molecule of pyrazinoic acid (POA) in the asymmetric unit. In the crystal, the PABA and POA molecules are associated via COOH...Naromheterosynthons, which are connected by N—H...O hydrogen bonds, creating zigzag chains. The chains are further linked by N—H...O hydrogen bonds and π–π stacking interactions along thebaxis [centroid-to-centroid distances = 3.7377 (13) and 3.8034 (13) Å at 150 and 293 K, respectively] to form a layered three-dimensional structure.


2017 ◽  
Vol 73 (6) ◽  
pp. 464-469 ◽  
Author(s):  
Juan Liu ◽  
Yang-Rong Xu ◽  
Xing-Si An ◽  
Gui-Ge Hou ◽  
Qing-Guo Meng

In order to study the in vivo protective effect on myocardial ischemia, (20S,24R)-epoxydammarane-12β,25-diol, (V), and (20S,24S)-epoxydammarane-12β,25-diol, (VI), were synthesized through a novel synthetic route. Two key intermediates, namely (20S,24R)-3-acetyl-20,24-epoxydammarane-3β,12β,25-triol, (III) [obtained as the hemihydrate, C32H54O5·0.5H2O, (IIIa), and the ethanol hemisolvate, C32H54O5·0.5C2H5OH, (IIIb), with identical conformations but different crystal packings], and (20S,24S)-3-acetyl-20,24-epoxydammarane-3β,12β,25-triol, C32H54O5, (IV), were obtained during the synthesis. The structures were confirmed by 1H NMR, 13C NMR and HRMS analyses, and single-crystal X-ray diffraction. Molecules of (IIIa) are extended into a two-dimensional network constructed with water molecules linked alternately through intermolecular O—H...O hydrogen bonds, which are further stacked into a three-dimensional network. Compound (IIIb) contains two completely asymmetric molecules, which are linked in a disordered manner through intermolecular C—H...O hydrogen bonds. While the crystal stacks in compound (IV) are linked via weak C—H...O hydrogen bonds, the hydrogen-bonded chains extend helically along the crystallographic b axis.


1972 ◽  
Vol 50 (8) ◽  
pp. 1134-1143 ◽  
Author(s):  
G. Kemper ◽  
Aafje Vos ◽  
H. M. Rietveld

The crystal structure of KIO3•HIO3 has been determined by three-dimensional single crystal X-ray diffraction and by neutron powder diffraction. The crystallographic data are a = 7.025(2), b = 8.206(2), c = 21.839(5) Å, β = 97.98(2)°, space group P21/c, Z = 8 units KIO3•HIO3. The residual [Formula: see text] was 0.048 for 7516 independent X-ray reflections measured on a three-circle diffractometer with Zr-filtered Mo radiation. The results of the present study show good qualitative agreement with the structure recently determined by Chan and Einstein (7). The HIO3 and [Formula: see text] groups are pyramidal, the I—O(H) bonds vary from 1.898 to 1.939(4) Å and the I—O bonds from 1.786 to 1.827(4) Å, these lengths are not corrected for the effects of thermal motion. Strong O—I … O interactions and electrostatic attractions between K+ and Oδ− give slabs of thickness [Formula: see text] The slabs are connected by hydrogen bonds of 2.710 and 2.694 Å.


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