0000000000083072
AUTHOR
Inese Sarcevica
Enrichment and activation of smectite-poor clay
A new method of smectite clay enrichment has been developed. The method is based on dispersing clay in a phosphate solution and sequential coagulation. The product of enrichment is characterized with X-ray powder diffraction, wavelength dispersive X-ray fluorescence spectrometry, differential thermal analysis and thermogravimetry. Sorption of methylene blue and hexadecylpyridinium bromide on raw and purified clays was studied.
Solvates of Dasatinib: Diversity and Isostructurality
A series of dasatinib crystalline forms were obtained, and a hierarchical cluster analysis of their powder X-ray diffraction patterns was performed. The resulting dendrogram implies 3 structural groups. The crystal structures of several solvates representing 2 of these groups were determined. The crystal structure analysis confirms the isostructurality of solvates within structural group I and suggests a correlation between solvent molecule size and trends in crystal structures within this group. In addition, the formation relationships in 2-solvent media between different dasatinib solvate groups were determined. The formation preference of solvates was found to follow the ranking group I …
Conformation of the umifenovir cation in the molecular and crystal structures of four carboxylic acid salts
The umifenovir salts of maleic, salicylic, glutaric, and gentisic acid as well as the chloroform solvate of the salicylate were prepared. Single crystals of the five compounds were obtained and their molecular and crystal structures determined by X-ray diffraction. In each structure the conformation of phenyl ring with respect to the indole group of the umifenovir moiety is different. The water solubility and melting points of the studied umifenovir salts have been determined.
Isoniazid cocrystallisation with dicarboxylic acids: vapochemical, mechanochemical and thermal methods
Cocrystallisation with a series of related compounds allows for the exploration of trends and limitations set by structural differences between these compounds. In this work, we investigate how the length of a dicarboxylic acid influences the outcome of cocrystallisation with isoniazid. We have performed a systematic study on the mechanochemical, thermal and solvent vapour-assisted cocrystallisation of aliphatic dicarboxylic acids (C3–C10) with isoniazid. Our results demonstrate that the rate of mechanochemical and vapour-assisted cocrystallisation depends on the acid chain length and shows alternation between odd- and even-chain acids. The results of thermal cocrystallisation showed that t…
Crystal and Molecular Structure and Stability of Isoniazid Cocrystals with Selected Carboxylic Acids
Reaction of isoniazid with benzoic acid, sebacic acid, suberic acid, and cinnamic acid results in formation of cocrystals. Two polymorphs of isoniazid–suberic acid and two polymorphs of isoniazid–cinnamic acid cocrystals were isolated. Crystal structure analysis shows the presence of a pyridine–carboxylic acid synthon in the studied cocrystals. The hydrazide group of isoniazid participates in N–H···O and N–H···N hydrogen bond formation, producing different supramolecular synthons. The stability study of isoniazid cocrystals has been performed over a 22 week period. A comparison of melting points of isoniazid–dicarboxylic acid 2:1 cocrystals shows the decrease of melting point with an increa…
The effect of pH on polymorph formation of the pharmaceutically active compound tianeptine.
The anti-depressant pharmaceutical tianeptine has been investigated to determine the dynamics of polymorph formation under various pH conditions. By varying the pH two crystalline polymorphs were isolated. The molecular and crystal structures have been determined to identify the two polymorphs. One polymorph is an amino carboxylic acid and the other polymorph is a zwitterion. In the solid state the tianeptine moieties are bonded through hydrogen bonds. The zwitterion was found to be less stable and transformed to the acid form. During this investigation an amorphous form was identified.
The Preparation and Characterization of New Antazoline Salts with Dicarboxylic Acids
New antazoline salts with organic acids (fumaric acid, oxalic acid, and maleic acid) were prepared. The effect of the crystallization solvent and mechanochemical treatment on the crystalline forms of these salts was studied. Two polymorphs of antazoline hydrogen maleate were identified and their relative stability was determined. The molecular structures of antazoline hydrogen oxalate and antazoline hydrogen maleate showed differences in antazoline cation conformation. In crystal structures of all salts both imidazoline nitrogens of antazoline cation are involved in hydrogen bond formation with carboxyl groups of the acid.
Spontaneous cocrystal hydrate formation in the solid state: crystal structure aspects and kinetics
Kinetics of anhydrous cocrystal hydration and that of cocrystal monohydrate formation from starting compounds in the solid state are studied as a function of RH and time. The propensity of the anhydrate to hydration is related to the crystal structures of anhydrous and hydrated forms.
The conformation of pyrogallol as a result of cocrystallization with N-heterocyclic bases
Structural analysis of the supramolecular cocrystals formed by pyrogallol with acridine, 4,4′-bipyridine, and 1,10-phenanthroline shows that the studied cocrystals are assembled via the hydroxyl–pyridine heterosynthon. In the crystal and molecular structures of these cocrystals in order to form the maximum number of hydrogen bonds, taking into consideration steric effects, the pyrogallol moiety in the supramolecular arrangement has the following conformations: with acridine - syn1, 4,4′-bipyridine - anti, and 1,10-phenanthroline - syn2. Discrete supramolecular complexes are formed by acridine–pyrogallol and the 1,10-phenanthroline–pyrogallol polymorph I. The 1,10-phenanthroline–pyrogallol p…
A Maze of Solid Solutions of Pimobendan Enantiomers: An Extraordinary Case of Polymorph and Solvate Diversity
Over 10 polymorphs and solvatomorphs of the chiral pharmaceutically active ingredient pimobendan were found to lack enantioselectivity in the solid state, accordingly, forming solid solutions of enantiomers, which is reported to be a rare phenomenon. Solid form screening was performed on different enantiomeric composition samples to analyze obtained phases with powder X-ray diffraction and thermogravimetric differential scanning calorimetry. For nonsolvated forms, a melt phase diagram has been constructed convincingly showing the existence of stable and metastable solid solutions near the pure enantiomer and around the racemic composition regions. A crystal structure study combined with sol…
CCDC 931509: Experimental Crystal Structure Determination
Related Article: Liana Orola, Inese Sarcevica, Artis Kons, Andris Actins, Mikelis V. Veidis|2014|J.Mol.Struct.|1056|63|doi:10.1016/j.molstruc.2013.10.010
CCDC 931507: Experimental Crystal Structure Determination
Related Article: Liana Orola, Inese Sarcevica, Artis Kons, Andris Actins, Mikelis V. Veidis|2014|J.Mol.Struct.|1056|63|doi:10.1016/j.molstruc.2013.10.010
CCDC 931511: Experimental Crystal Structure Determination
Related Article: Liana Orola, Inese Sarcevica, Artis Kons, Andris Actins, Mikelis V. Veidis|2014|J.Mol.Struct.|1056|63|doi:10.1016/j.molstruc.2013.10.010
CCDC 890182: Experimental Crystal Structure Determination
Related Article: Inese Sarcevica, Liana Orola, Mikelis V.Veidis, Anton Podjava, and Sergey Belyakov|2013|Cryst.Growth Des.|13|1082|doi:10.1021/cg301356h
CCDC 931510: Experimental Crystal Structure Determination
Related Article: Liana Orola, Inese Sarcevica, Artis Kons, Andris Actins, Mikelis V. Veidis|2014|J.Mol.Struct.|1056|63|doi:10.1016/j.molstruc.2013.10.010
CCDC 1050684: Experimental Crystal Structure Determination
Related Article: Toms Rekis, Agris Be¯rzinš, Inese Sarcevica, Artis Kons, Ma¯rtinš Balodis, Lia¯na Orola, Heike Lorenz, Andris Actinš|2018|Cryst.Growth Des.|18|264|doi:10.1021/acs.cgd.7b01203
CCDC 890184: Experimental Crystal Structure Determination
Related Article: Inese Sarcevica, Liana Orola, Mikelis V.Veidis, Anton Podjava, and Sergey Belyakov|2013|Cryst.Growth Des.|13|1082|doi:10.1021/cg301356h
CCDC 890181: Experimental Crystal Structure Determination
Related Article: Inese Sarcevica, Liana Orola, Mikelis V.Veidis, Anton Podjava, and Sergey Belyakov|2013|Cryst.Growth Des.|13|1082|doi:10.1021/cg301356h
CCDC 890180: Experimental Crystal Structure Determination
Related Article: Inese Sarcevica, Liana Orola, Mikelis V.Veidis, Anton Podjava, and Sergey Belyakov|2013|Cryst.Growth Des.|13|1082|doi:10.1021/cg301356h
CCDC 1571124: Experimental Crystal Structure Determination
Related Article: Toms Rekis, Agris Be¯rzinš, Inese Sarcevica, Artis Kons, Ma¯rtinš Balodis, Lia¯na Orola, Heike Lorenz, Andris Actinš|2018|Cryst.Growth Des.|18|264|doi:10.1021/acs.cgd.7b01203
CCDC 890183: Experimental Crystal Structure Determination
Related Article: Inese Sarcevica, Liana Orola, Mikelis V.Veidis, Anton Podjava, and Sergey Belyakov|2013|Cryst.Growth Des.|13|1082|doi:10.1021/cg301356h
CCDC 933429: Experimental Crystal Structure Determination
Related Article: Inese Sarcevica, Liana Orola, Sergey Belyakov, Mikelis V. Veidis|2013|New J.Chem.|37|2978|doi:10.1039/C3NJ00489A
CCDC 931508: Experimental Crystal Structure Determination
Related Article: Liana Orola, Inese Sarcevica, Artis Kons, Andris Actins, Mikelis V. Veidis|2014|J.Mol.Struct.|1056|63|doi:10.1016/j.molstruc.2013.10.010