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Journal articles on the topic 'Polymorphic Forms'

Author: Grafiati

Published: 4 June 2021

Last updated: 6 September 2023

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1

G, Nithya, Sudha R, and Charles C. Kanakam. "Polymorphic behavior of an organic compound." Asian Journal of Pharmaceutical and Clinical Research 10, no. 4 (2017): 259. http://dx.doi.org/10.22159/ajpcr.2017.v10i4.16702.

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Objective: Polymorphic crystals were exhibited in many organic compounds. The frequency changes, relative intensities, band contours, and numberof bands were observed in the spectra of different polymorphism which may be due to molecule-molecule interactions in the crystal unit cells. Theshape of a molecule at its site in the unit cell is distorted by molecular interactions.Methods: The identification of a pure crystal form and to quantify a mixture of two forms infrared and Raman spectra of different crystalline formsof the same organic compound can be used. 2’-chloro-4-methoxy-3-nitro benzil

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2

Kuzmin, V. S., V. V. Chernyshev, and A. I. Luttseva. "X-RAY POWDER DIFFRACTION IN QUALITY CONTROL OF MEDICINES." Bulletin of the Scientific Centre for Expert Evaluation of Medicinal Products 8, no. 3 (2018): 158–61. http://dx.doi.org/10.30895/1991-2919-2018-8-3-158-161.

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X-ray powder diffraction is one of the methods used for detection and analysis of polymorphic forms of pharmaceutical substances. The article elucidates the concept of polymorphism, briefly explains physical characteristics of this phenomenon, conditions of polymorphic transformations and the prevalence of polymorphic forms among drug substances. It should be noted that polymorphism is observed in drug substances belonging to different pharmacologic classes. Polymorphic forms of the same drug substance have different solubility, melting point, resistance to oxidation and to other destructive p

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3

Takeguchi, Seiya, Arisa Sato, Hironori Hondoh, Mio Aoki, Hidetaka Uehara та Satoru Ueno. "Multiple β Forms of Saturated Monoacid Triacylglycerol Crystals". Molecules 25, № 21 (2020): 5086. http://dx.doi.org/10.3390/molecules25215086.

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We have investigated the polymorphism of triacylglycerol (TAG) crystals as they affect the qualities such as shelf life, mouth feel, and texture of chocolate and other products. Saturated monoacid TAGs, like trilaurin, are considered as models for TAG crystallization; however, there is still debate about the number of their polymorphs that exist. In this study, we characterized a set of novel polymorphs, β forms of saturated monoacid TAGs, which were obtained via different pathways depending on the crystallization history, by polarized light microscopy, X-ray diffraction, and differential scan

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4

Rajendrakumar, Satyasree, Anuja Surampudi Venkata Sai Durga, Jagadeesh Babu Nanubolu, and Sridhar Balasubramanian. "Two novel polymorphic forms of iron-chelating agent deferiprone." Acta Crystallographica Section C Structural Chemistry 76, no. 2 (2020): 193–200. http://dx.doi.org/10.1107/s2053229620000959.

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Thalassemia is a genetic blood disorder requiring life-long blood transfusions. This process often results in iron overload and can be treated by an iron-chelating agent, like deferiprone (3-hydroxy-1,2-dimethylpyridin-4-one), C7H9NO2, in an oral formulation. The first crystal structure of deferiprone, (Ia), was reported in 1988 [Nelson et al. (1988). Can. J. Chem. 66, 123–131]. In the present study, two novel polymorphic forms, (Ib) and (Ic), of deferiprone were identified concomitantly with polymorph (Ia) during the crystallization experiments. Polymorph (Ia) was redetermined at low temperat

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5

Hsu, Cheng-Hung, Wen-Ting Ke, and Shan-Yang Lin. "Progressive Steps of Polymorphic Transformation of Gabapentin Polymorphs Studied by Hot-stage FTIR Microspectroscopy." Journal of Pharmacy & Pharmaceutical Sciences 13, no. 1 (2010): 67. http://dx.doi.org/10.18433/j3fs32.

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Purpose. The aim of this study was to determine the progressive processes of polymorphic transformation of different gabapentin (GBP) polymorphs by using hot-stage Fourier transform infrared (FTIR) microspectroscopy. Methods. Four polymorphs of GBP were previously prepared and then identified by differential scanning calorimetry (DSC), thermogravimetric (TG) analysis, FTIR microspectroscopy and X-ray powder diffractometry. A novel hot-stage FTIR microspectroscopic technique was used to investigate the progressive steps of polymorphic transformation of each GBP polymorph sealed within two piece

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6

Akune, Yoko, Risa Hirosawa, Atsushi Koseki, and Shinya Matsumoto. "Role of halogen substituents in a series of polymorphic 2,5-diamino-3,6-dicyanopyrazine derivatives with highly flexible groups." Zeitschrift für Kristallographie - Crystalline Materials 232, no. 5 (2017): 395–405. http://dx.doi.org/10.1515/zkri-2016-2007.

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AbstractThe crystal structures of the ortho-X-benzyl derivatives, where X=F, Cl, Br, I, and Me, of 2,5-bis(N,N-dibenzylamino)-3,6-dicyanopyrazine dyes (C34H24N6X4) were analysed to evaluate the effect of a systematic series of structures on the occurrence of polymorphism. Detailed crystal structure analysis indicated that the thermally stable forms of the polymorphic derivatives (Cl and Br derivatives) were close-packed, whereas those of the non-polymorphic derivatives (F and I derivatives) were stabilised by an intermolecular interaction involving the ortho-substituents. In the thermally meta

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7

Paczkowska, Magdalena, Gabriela Wiergowska, Andrzej Miklaszewski, et al. "The Analysis of the Physicochemical Properties of Benzocaine Polymorphs." Molecules 23, no. 7 (2018): 1737. http://dx.doi.org/10.3390/molecules23071737.

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The study was a pioneering attempt to assess the influence of the structural polymorphism (forms I, II, III) of benzocaine on its solubility, apparent solubility, and chemical stability, which are vital parameters for preformulation and formulation work. The impact of differences in the solubility of selected polymorphs of benzocaine on their permeability through artificial biological membranes (PAMPA system) was evaluated. The polymorphs of benzocaine were obtained by means of techniques commonly used for the preparation of various pharmaceutical dosage forms: ball milling, micro milling, and

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8

Ângelo, Marilene, Jennifer Jacon, Olimpia Maria Santos, et al. "Occurrence of polymorphism in famotidine raw materials." Acta Crystallographica Section A Foundations and Advances 70, a1 (2014): C1563. http://dx.doi.org/10.1107/s2053273314084368.

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Polymorphs are compounds with the same chemical composition, however the molecules are arranged in at least two different ways in the solid state. Famotidine is a histamine H2-receptor antagonist inhibitor of gastric secretion and widely used in gastric and duodenal ulcer disease. Two polymorphs are described for famotidine, A and B. The polymorph A is the most thermodynamically stable form and polymorph B is the kinetically favored form being marketed because it presents greater pharmacological activity. The aim of this study was to evaluate the occurrence of famotidine polymorphs in five raw

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9

So, Hee-Soo, and Shinya Matsumoto. "Three differently coloured polymorphs of 3,6-bis(4-chlorophenyl)-2,5-dipropyl-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione." Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials 75, no. 3 (2019): 414–22. http://dx.doi.org/10.1107/s2052520619004773.

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In this paper, the conformational polymorphism of a chlorinated diketopyrrolopyrrole (DPP) dye having flexible substituents in a non-hydrogen-bonding system is reported. The propyl-substituted DPP derivative (PR3C) has three polymorphic forms, each showing a different colour (red, orange and yellow). All polymorphs could be obtained concomitantly under various crystallization conditions. The results of the crystal structure analysis indicate that PR3C adopts different conformations in each polymorph. The packing effect caused by the difference in the arrangement of neighbouring molecules was f

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10

Czernek, Jiří, and Jiří Brus. "Polymorphic Forms of Valinomycin Investigated by NMR Crystallography." International Journal of Molecular Sciences 21, no. 14 (2020): 4907. http://dx.doi.org/10.3390/ijms21144907.

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A dodecadepsipeptide valinomycin (VLM) has been most recently reported to be a potential anti-coronavirus drug that could be efficiently produced on a large scale. It is thus of importance to study solid-phase forms of VLM in order to be able to ensure its polymorphic purity in drug formulations. The previously available solid-state NMR (SSNMR) data are combined with the plane-wave DFT computations in the NMR crystallography framework. Structural/spectroscopical predictions (the PBE functional/GIPAW method) are obtained to characterize four polymorphs of VLM. Interactions which confer a confor

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11

Pogoda, Dorota, Jan Janczak, and Veneta Videnova-Adrabinska. "New polymorphs of an old drug: conformational and synthon polymorphism of 5-nitrofurazone." Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials 72, no. 2 (2016): 263–73. http://dx.doi.org/10.1107/s2052520615024956.

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Two new polymorphic forms of 5-nitrofurazone (5-nitro-2-furaldehyde semicarbazone) have been synthesized and structurally characterized by single-crystal and powder X-ray diffraction methods, vibrational spectroscopy (FT–IR and temperature Raman), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and Hirshfeld surface analysis. The compound crystallizes in three different polymorphic formsP21/a(polymorph α),P21(polymorph β) andP21/c(polymorph γ), the crystal structures of two of which (polymorphs β and γ) represent new structure determinations. The solid-state molecular

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12

Jurek, Paul, Garry E. Kiefer, and Frank R. Fronczek. "Crystal structures of two polymorphic forms of DOTAM-mono-acid dihydrate." Acta Crystallographica Section C Structural Chemistry 74, no. 5 (2018): 542–47. http://dx.doi.org/10.1107/s2053229618004631.

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The structural chemistry of 2-[4,7,10-tris(carbamoylmethyl)-1,4,7,10-tetraazacyclododecan-1-yl]acetic acid dihydrate, C16H31N7O5·2H2O, is described. The macrocyclic compound, also known by the abbreviation DOTAM-mono-acid, crystallized at room temperature and was isolated concomitantly as two polymorphic forms. The structures of both polymorphs were determined at 90 K. The first polymorph crystallized as a zwitterionic dihydrate [systematic name: 4,7,10-tris(carbamoylmethyl)-1-(carboxylatomethyl)-1,4,7,10-tetraazacyclododecan-1-ium dihydrate] in the space group P21/n, with Z′ = 1. The second p

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13

Kempa, Arnold, and Jan Dobrowolski. "Palladium phthalocyanine and its polymorphic forms." Canadian Journal of Chemistry 66, no. 10 (1988): 2553–55. http://dx.doi.org/10.1139/v88-400.

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Pd(II) phthalocyanine (PdPc) was obtained by reaction of PdCl2 with phthalimide and urea in the presence of ammonium molybdate in boiling nitrobenzene, resulting in a good yield equal to 68%. This method has not been used previously. The following polymorphic forms were obtained: metastable α- and γ-PdPc, not previous described in the literature, and stable β-PdPc. The IR spectra and X-ray powder diffraction spectra of these phases were measured and interpreted. The results were compared with the literature data on polymorphic forms of other phthalocyanines. At this time we do not know if any

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14

Chadha, Renu, Poonam Arora, Anupam Saini, and Dharamvir Singh Jain. "An Insight into Thermodynamic Relationship Between Polymorphic Forms of Efavirenz." Journal of Pharmacy & Pharmaceutical Sciences 15, no. 2 (2012): 234. http://dx.doi.org/10.18433/j3j30z.

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Purpose: The aim of the work is to study the crystallization of efavirenz to understand the preferential formation of various polymorphic forms, to establish their identity, to study the transformation between the polymorphic forms on heating and to determine their free energy. Methods: Slow crystallization from different solvents under controlled conditions was employed to prepare various crystalline forms. The TGA and DSC were used to study their thermal behavior and inter-conversion of these forms. The calorimetrically determined enthalpies of solution and solubility data are utilized to de

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15

Falk, Jacqueline, Detlef Hofmann, and Klaus Merz. "Controlled usage of H/D exchange to circumvent concomitant polymorphs of ROY." IUCrJ 5, no. 5 (2018): 569–73. http://dx.doi.org/10.1107/s2052252518009995.

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The hypothesis that H/D exchange affects the structural formation of organic compounds in the solid state is supported by a deeper understanding of the altering polymorphism of ROY (a substance striking for its high number of polymorphic forms) through deuteration. Therefore, ROY was deuterated at its amine function, which leads to a seemingly small yet effective modification of the hydrogen-bond strength. In contrast to the crystallization of the non-deuterated ROY in methanol or ethanol, which leads to the simultaneous formation of two forms (OP and Y polymorphs), so-called concomitant polym

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16

Wójcik, Grażyna, and Izabela Mossakowska. "Polymorphs of p-nitrophenol as studied by variable-temperature X-ray diffraction and calorimetry: comparison with m-nitrophenol." Acta Crystallographica Section B Structural Science 62, no. 1 (2006): 143–52. http://dx.doi.org/10.1107/s010876810503418x.

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Crystal structures of two polymorphic forms of p-nitrophenol have been determined at several temperatures between 120 and 375 K. The thermal expansion tensor has been determined for both polymorphs. The rigid-body mean-square amplitudes of molecular translations and librations and the amplitudes of the internal torsions of the nitro group have been calculated at different temperatures. Differential scanning calorimetry was used to find the temperature and enthalpy of the polymorphic transformation. The results were compared with those recently obtained for m-nitrophenol polymorphs. Some conclu

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17

Mareczek, Lena, Carolin Riehl, Meike Harms, and Stephan Reichl. "Understanding the Multidimensional Effects of Polymorphism, Particle Size and Processing for D-Mannitol Powders." Pharmaceutics 14, no. 10 (2022): 2128. http://dx.doi.org/10.3390/pharmaceutics14102128.

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The relevance of the polymorphic form, particle size, and processing of mannitol for the mechanical properties of solid oral dosage forms was examined. Thus, particle and powder properties of spray granulated β D-mannitol, β D-mannitol, and δ D-mannitol were assessed in this study with regards to their manufacturability. D-mannitol is a commonly used excipient in pharmaceutical formulations, especially in oral solid dosage forms, and can be crystallized as three polymorphic forms, of which β is the thermodynamically most stable form and δ is a kinetically stabilized polymorph. A systematic ana

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18

Kogawa, Ana Carolina, Selma Gutierrez Antonio, and Hérida Regina Nunes Salgado. "Characterization of Polymorphic Forms of Rifaximin." Journal of AOAC INTERNATIONAL 99, no. 4 (2016): 964–71. http://dx.doi.org/10.5740/jaoacint.16-0053.

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Abstract Rifaximin is a gut-selective oral antimicrobial that has no systemic adverse effects compared with placebo. It is used for the treatment of hepatic encephalopathy, traveler's diarrhea, irritable bowel syndrome, Clostridium difficile infection, ulcerative colitis, and acute diarrhea. The crystalline form present in rifaximin, α, has minimal systemic absorption compared to the amorphous form. The objective of this study was to obtain polymorphic forms of rifaximin using recrystallization processes. The forms were characterized and studied by thermal analysis, X-ray powder diffraction, s

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Schmidtmann, Marc, Derek S. Middlemiss, and Chick C. Wilson. "Isotopomeric polymorphism in a “doubly-polymorphic” multi-component molecular crystal." CrystEngComm 17, no. 28 (2015): 5273–79. http://dx.doi.org/10.1039/c5ce00123d.

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Isotopomeric polymorphism is observed in complexes of isonicotinamide with oxalic acid, highly unusual here in that each isotopic complex is itself polymorphic, a situation of “double polymorphism”. The four polymorphic forms exhibit different degrees of hydron transfer.

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Whittall, Linda B., Robert R. Whittle, and Grayson W. Stowell. "Polymorphic forms of cilostazol." Acta Crystallographica Section C Crystal Structure Communications 58, no. 8 (2002): o525—o527. http://dx.doi.org/10.1107/s0108270102012544.

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21

Wardhana, Yoga Windhu, Risanteni Riskasari, and Fikri Alatas. "Phase Transitions Among of Valsartan Polymorphs due to Grinding and Humidity Variations." Indonesian Journal of Pharmaceutics 3, no. 2 (2021): 82. http://dx.doi.org/10.24198/idjp.v3i2.35312.

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Phase transition between drugs with polymorphisms needs attention due to unconscious changes in quality. Valsartan (VAL) is a drug model with polymorphic events to be studied here. Two polymorphic forms were obtained from recrystallization with various organic solvents such as acetonitrile and n-butyl acetate. With untreated materials (from the market) were used as a comparison in this study. The phase transition of each polymorph was studied through grinding and humidity variations (RH 75% and 98%) treatment. The polymorph characterization was observed by microscope light polarization (PLM),

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DELGADO, G., M. GUILLEN, and A. J. MORA. "4-METHYL HYPPURIC ACID: A CASE OF POLYMORPHISM AND SOLVATOMORPHISM." Periódico Tchê Química 16, no. 32 (2019): 812–19. http://dx.doi.org/10.52571/ptq.v16.n32.2019.830_periodico32_pgs_812_819.pdf.

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Polymorphism is known as the ability of a solid material to exist in more than one form or crystal structure, with important applications in the preparation of active pharmaceutical ingredients. Characterization of different polymorphs of the specific metabolite of 4-xylene can contribute to the chemical and pharmaceutical industry. Polymorphism is of particular importance in industrial processes, where different physical properties of polymorphic forms can substantially alter the viability and quality of a manufactured product. This is particularly so for the design and production of drugs in

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23

Mapp, Lucy, Mateusz Pitak, Simon Coles, and Srinivasulu Aitipamula. "Charge density studies on 1:1 co-crystals of ethenzamide and saccharin." Acta Crystallographica Section A Foundations and Advances 70, a1 (2014): C964. http://dx.doi.org/10.1107/s2053273314090354.

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The study of multi-component crystals, as well as the phenomenon of polymorphism, both have relevance to crystal engineering. Obtaining a specific polymorph is crucial as different polymorphs usually exhibit different physical and chemical properties and often the origin of this behaviour is unknown. This is especially important in the pharmaceutical industry. Herein, we present results of comparative studies of an analgesic drug, ethenzamide and its co-crystals with saccharin. The co-crystalisation of ethenzamide (2-ethoxybenzamide, EA) with saccharin (1,1-dioxo-,1,2-benzothiazol-3-one, SAC)

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Britton, Doyle, Victor G. Young, Wayland E. Noland, Matthew J. Pinnow, and Christopher M. Clark. "Four polymorphs (polytypes) of 5,6-dimethylbenzofurazan 1-oxide." Acta Crystallographica Section B Structural Science 68, no. 5 (2012): 536–42. http://dx.doi.org/10.1107/s0108768112037457.

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5,6-Dimethylbenzofurazan 1-oxide (Me2BF), C8H8N2O2, occurs in four polymorphic forms that are polytypes of each other. Each polymorph of Me2BF contains molecules disordered about pseudo-twofold axes and arranged head-to-tail in ribbons, with the ribbons forming approximately planar layers held together by weak C—H...N and C—H...O interactions. Adjacent layers interact in different ways in the different polymorphs. In addition to twinning in the individual polymorphs, four examples of allotwining, that is, oriented overgrowths between different polymorphs, were found.

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Hean, Duane, Andreas Lemmerer, and Joseph Michael. "Rampant Polymorphism in Pharmaceuticals: An Isoniazid Derivative." Acta Crystallographica Section A Foundations and Advances 70, a1 (2014): C653. http://dx.doi.org/10.1107/s2053273314093462.

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Investigations into the polymorphic forms of Active Pharmaceutical Ingredients (APIs) are of vital importance to drug formulations and are often kept a closely guarded secret by pharmaceutical companies. This secrecy is maintained as the nature of the polymorph could either make or break a drug formulation. Polymorphism is the ability of a solid crystalline form to exist in more than one structural arrangement. The variation in the crystalline forms often displays different mechanical, thermal, and chemical properties. These changes can remarkably influence the bioavailability, hygroscopicity,

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Jakli, A., I. Janossy, and A. Vajda. "Polymorphic crystalline forms of 8OCB." Liquid Crystals 27, no. 8 (2000): 1035–38. http://dx.doi.org/10.1080/02678290050080779.

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Baraldi, C., A. Tinti, S. Ottani, and M. C. Gamberini. "Characterization of polymorphic ampicillin forms." Journal of Pharmaceutical and Biomedical Analysis 100 (November 2014): 329–40. http://dx.doi.org/10.1016/j.jpba.2014.08.021.

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Hassan, Mohamad A., Mutaz Sheikh Salem, Mohammad S. Sueliman, and Naji M. Najib. "Characterization of famotidine polymorphic forms." International Journal of Pharmaceutics 149, no. 2 (1997): 227–32. http://dx.doi.org/10.1016/s0378-5173(97)04872-2.

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Detrich, Ádám, Kata Judit Dömötör, Miklós Tamás Katona, Imre Markovits, and Judit Vargáné Láng. "Polymorphic forms of bisoprolol fumarate." Journal of Thermal Analysis and Calorimetry 135, no. 6 (2018): 3043–55. http://dx.doi.org/10.1007/s10973-018-7553-8.

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Ainurofiq, Ahmad, Kezia Esther Dinda, Maya Widia Pangestika, Ulia Himawati, Wening Dyah Wardhani, and Yustika Tamarin Sipahutar. "The effect of polymorphism on active pharmaceutical ingredients: A review." International Journal of Research in Pharmaceutical Sciences 11, no. 2 (2020): 1621–30. http://dx.doi.org/10.26452/ijrps.v11i2.2044.

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Active pharmaceutical ingredients (API) are the main components in the production process of pharmaceutical products. If the API has a good quality, then it will lead to good pharmaceutical products. API consists of more than one different crystal form which, then forms a polymorph through the process of polymorphism. Until now, API polymorphism is still a big challenge in the pharmaceutical industry. That is because the nature of polymorphism is difficult to predict. One of them is by crystallizing molecules in one or many crystalline forms or combining with other molecules to form stable co-

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Mohan, Shikhar, Yi Li, Kevin Chu, et al. "Developing In Situ Chemometric Models with Raman Spectroscopy for Monitoring an API Disproportionation with a Complex Polymorphic Landscape." Pharmaceuticals 16, no. 2 (2023): 327. http://dx.doi.org/10.3390/ph16020327.

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An in situ Raman method was developed to characterize the disproportionation of two salts involving a complex polymorphic landscape comprising up to two metastable and one stable freebase forms. Few precedents exist for Raman calibration procedures for solid form quantitation involving more than two polymorphs, while no literature examples were found for cases with multiple metastable forms. Therefore, a new Raman calibration procedure was proposed by directly using disproportionation experiments to generate multiple calibration samples encompassing a range of polymorph ratios through in-line

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Sun, Mengying, Xiurong Hu, Xinbo Zhou, and Jianming Gu. "Determination of minor quantities of linezolid polymorphs in a drug substance and tablet formulation by powder X-ray diffraction technique." Powder Diffraction 32, no. 2 (2017): 78–85. http://dx.doi.org/10.1017/s0885715617000069.

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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 singl

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Byrne, Jonathan, Robert Reinhardt, and Trinidad Velasco-Torrijos. "Polymorphism in Commercial Sources of Fusidic Acid: A Comparative Study of the In Vitro Release Characteristics of Forms I and III from a Marketed Pharmaceutical Cream." Journal of Analytical Methods in Chemistry 2017 (2017): 1–7. http://dx.doi.org/10.1155/2017/3493096.

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A comparison of the polymorphic forms of 3 commercial sources of fusidic acid using FTIR and XRPD techniques has been performed in this study. It has been demonstrated that polymorphic Forms I and III are currently available on the commercial market. The influence of the observed polymorphism on the stability of the drug substance in bulk form has been investigated through stability and stress testing according to current ICH guidelines. Significant differences were detected between commercial sources with regard to the stability of the bulk substance under photolytic and humidity stress condi

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Declerck, Arnout, Veronique Nelis, Sabine Danthine, Koen Dewettinck, and Paul Van der Meeren. "Characterisation of Fat Crystal Polymorphism in Cocoa Butter by Time-Domain NMR and DSC Deconvolution." Foods 10, no. 3 (2021): 520. http://dx.doi.org/10.3390/foods10030520.

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The polymorphic state of edible fats is an important quality parameter in fat research as well as in industrial applications. Nowadays, X-ray diffraction (XRD) is the most commonly used method to determine the polymorphic state. However, quantification of the different polymorphic forms present in a sample is not straightforward. Differential Scanning Calorimetry (DSC) is another method which provides information about fat crystallization processes: the different peaks in the DSC spectrum can be coupled to the melting/crystallisation of certain polymorphs. During the last decade, nuclear magne

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Al-Hmoud, Linda, Deeb Abu Fara, Iyad Rashid, Babur Z. Chowdhry, and Adnan A. Badwan. "Influence of Chitin Source and Polymorphism on Powder Compression and Compaction: Application in Drug Delivery." Molecules 25, no. 22 (2020): 5269. http://dx.doi.org/10.3390/molecules25225269.

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The objective of the research reported herein is to compare the compaction properties of three different chitin extracts from the organisms most used in the seafood industry; namely crabs, shrimps and squids. The foregoing is examined in relation to their polymorphic forms as well as compression and compaction behavior. Chitin extracted from crabs and shrimps exhibits the α-polymorphic form whilst chitin extracted from squid pins displays a β-polymorphic form. These polymorphs were characterized using FTIR, X-ray powder diffraction and scanning electron microscopy. Pore diameter and volume dif

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Chistyakov, Dmitry, and Gleb Sergeev. "The Polymorphism of Drugs: New Approaches to the Synthesis of Nanostructured Polymorphs." Pharmaceutics 12, no. 1 (2020): 34. http://dx.doi.org/10.3390/pharmaceutics12010034.

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Among the significant problems of modern pharmacology are the low solubility and bioavailability of drugs. One way to resolve this problem is to obtain new polymorphic forms of drugs with improved physicochemical properties. Various approaches have been developed with this aim, including the preparation of co-crystals, the use of nanoparticles, or the use of compounds in the form of a salt. A promising direction in pharmacology concerns the production of new stable polymorphic structures. In this mini-review, we consider certain aspects of drug polymorphism, methods for the synthesis of polymo

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Goyal, Parnika, Dimpy Rani, and Renu Chadha. "EXPLORING STRUCTURAL ASPECTS OF NATEGLINIDE POLYMORPHS USING POWDER X-RAY DIFFRACTION." International Journal of Pharmacy and Pharmaceutical Sciences 9, no. 10 (2017): 119. http://dx.doi.org/10.22159/ijpps.2017v9i10.20795.

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Objective: The present manuscript highlights the structural aspects of some polymorphic forms of nateglinide using powder x-ray diffraction (PXRD) pattern.Methods: All the polymorphic forms were isolated as microcrystalline powder, therefore, powder diffraction patterns was used as a tool to determine the crystal structure. For this, Reflux Plus module of BIOVIA Material Studio software was used. Polymorph prediction (PP) and crystal morphology analysis were performed to estimate the global minimum in lattice energy landscape and morphologically important (M. I.) facets, respectively. Besides

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Fedyanin, Ivan V., Aida I. Samigullina, Ivan A. Krutov, Elena L. Gavrilova, and Dmitry V. Zakharychev. "Structures of a Phosphoryl Derivative of 4-Allyl-2,4-dihydro-3H-1,2,4-triazole-3-thione: An Illustrative Example of Conformational Polymorphism." Crystals 11, no. 9 (2021): 1126. http://dx.doi.org/10.3390/cryst11091126.

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Two polymorphic forms of a conformationally flexible molecule, 5-[(Diphenylphosphoryl)methyl]-4-(prop-2-en-1-yl)-2,4-dihydro-3H-1,2,4-triazole-3-thione, were obtained by crystallization and characterized by X-ray diffraction analysis and differential scanning calorimetry. The relative stability of polymorphic forms was estimated with DFT calculations of crystal structures and isolated molecules. It turns out, that in the first more dense polymorph with higher cohesion energy and crystal lattice energy, the molecule adopts an energetically unfavorable conformation, and forms dimers with lower H

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Lukhanina, Natalia V., Marina G. Sinyavskaya, Inessa M. Goloenko, and Oleg G. Davydenko. "Chloroplast microsatellites in barley: the reduction of variability spectrum in cultivated forms." Ecological genetics 4, no. 1 (2006): 17–21. http://dx.doi.org/10.17816/ecogen4117-21.

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The chloroplast genomes of 67 accessions of Hordeum vulgare L were surveyed for simple sequence repeat polymorphism. Seven SSR loci were investigated, trnL/trnF and psbI-trnS intergenic regions, as well as two regions 3' trnS genes were polymorphic. The rare variants of these loci were revealed and five rare accessions were found. Our results show an extremely low level of cpDNA polymorphism of cultivated barley.

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Modec, Barbara. "Polymorphism ofmer-μ-oxalato-bis[chloridotripyridinecobalt(II)] pyridine disolvate". Acta Crystallographica Section C Crystal Structure Communications 69, № 4 (2013): 340–43. http://dx.doi.org/10.1107/s010827011300499x.

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Single crystals of a triclinic polymorphic form ofmer-μ-oxalato-bis[chloridotripyridinecobalt(II)] pyridine disolvate, [Co2(C2O4)Cl2(C5H5N)6]·2C5H5N, have been prepared by solvothermal methods. The structure and geometric parameters strongly resemble those of the previously reported monoclinic polymorph [Bolte (2006).Acta Cryst.E62, m597–m598]. In both polymorphic forms, the dinuclear complex molecules are located on a crystallographic centre of inversion, with the CoIIcations in a distorted octahedral environment consisting of a chloride ligand, three pyridine ligands and a chelating bis-bide

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Ghazani, Saeed M., and Alejandro G. Marangoni. "Molecular Origins of Polymorphism in Cocoa Butter." Annual Review of Food Science and Technology 12, no. 1 (2021): 567–90. http://dx.doi.org/10.1146/annurev-food-070620-022551.

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Cocoa butter displays complex crystallization behavior and six crystal polymorphic forms. Although the crystal structure of cocoa butter has been studied extensively, the molecular interactions between cocoa butter triacylglycerols in relation to polymorphic transformations from metastable forms (forms III and IV) to stable crystal forms (forms V and VI) remain largely unknown. In this review, the triclinic polymorphism and melting profiles of the major triacylglycerols in cocoa butter—POP, POS, and SOS—are reviewed, and their binary and ternary phase behaviors in metastable (pseudoβ′) and sta

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Ferreira da Silva, João Luís, M. Fátima Minas da Piedade, Vânia André, Sofia Domingos, Inês C. B. Martins, and M. Teresa Duarte. "The Lisbon Supramolecular Green Story: Mechanochemistry towards New Forms of Pharmaceuticals." Molecules 25, no. 11 (2020): 2705. http://dx.doi.org/10.3390/molecules25112705.

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This short review presents and highlights the work performed by the Lisbon Group on the mechanochemical synthesis of active pharmaceutical ingredients (APIs) multicomponent compounds. Here, we show some of our most relevant contributions on the synthesis of supramolecular derivatives of well-known commercial used drugs and the corresponding improvement on their physicochemical properties. The study reflects, not only our pursuit of using crystal engineering principles for the search of supramolecular entities, but also our aim to correlate them with the desired properties. The work also covers

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Prasad, A. Aditya, C. Udhaya Kumar, B. Arul Prakasam, and S. P. Meenakshisundaram. "Conformational polymorphs of isobutyl-6-amino-5-cyano-2-methyl-4-phenyl-4H-pyran-3-carboxylate: spectroscopic, structural and DFT approach." Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials 72, no. 3 (2016): 301–9. http://dx.doi.org/10.1107/s2052520616003310.

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The crystal structure of a new crystalline phase, polymorph (II) of isobutyl-6-amino-5-cyano-2-methyl-4-phenyl-4H-pyran-3-carboxylate, was accurately determined by single-crystal X-ray diffraction analysis providing a clean identification of polymorphic forms. Comparison with a known phase, referred to as polymorph (I), reveals the type of supramolecular assembly. Inter- and intramolecular hydrogen-bonding interactions exhibit various supramolecular architectures in crystal packing and these variations confirm well the polymorphism in isobutyl-6-amino-5-cyano-2-methyl-4-phenyl-4H-pyran-3-carbo

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Stöwe, Klaus, and Stephan Appel. "Polymorphic Forms of Rubidium Telluride Rb2Te." Angewandte Chemie International Edition 41, no. 15 (2002): 2725–30. http://dx.doi.org/10.1002/1521-3773(20020802)41:15<2725::aid-anie2725>3.0.co;2-g.

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Stowell, Grayson W., Robert J. Behme, Stacy M. Denton, et al. "Thermally-Prepared Polymorphic Forms of Cilostazol." Journal of Pharmaceutical Sciences 91, no. 12 (2002): 2481–88. http://dx.doi.org/10.1002/jps.10240.

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Chrobak, Elwira, Ewa Michalik, Joachim Kusz, Maria Nowak, and Stanisław Boryczka. "Polymorphic forms of lupane triterpenoid betulonic aldehyde (betulonal)." Acta Crystallographica Section C Structural Chemistry 70, no. 9 (2014): 847–51. http://dx.doi.org/10.1107/s2053229614017379.

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The lupane triterpenoid betulonic aldehyde [also known as betulonal; systematic name: lup-20(29)-en-28-al-3-one, C30H46O2] is a product of betulin oxidation. Crystals were obtained from hexane [form (I)] and dimethyl sulfoxide [form (II)] solutions. Forms (I) and (II) are both orthorhombic. The molecular geometric parameters in the two forms are similar, but the structures are different with respect to the crystal packing. Polymorph (I) contains two independent molecules in the asymmetric unit, while polymorph (II) contains only one molecule, which has a disordered aldehyde group [the disorder

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Kuang, Yun-Yan, Xuan Gao, Yi-Jun Niu, Xun-Long Shi, and Wei Zhou. "Polymorphic Characterization, Pharmacokinetics, and Anti-Inflammatory Activity of Ginsenoside Compound K Polymorphs." Molecules 26, no. 7 (2021): 1983. http://dx.doi.org/10.3390/molecules26071983.

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Polymorphism exhibits different physicochemical properties, which can impact the bioavailability and bioactivity of solid drugs. This study focused on identifying the polymorphs of ginsenoside compound K (CK) and studying their different behaviors in pharmacokinetics (PK) and pharmacodynamics (PD). Four CK polymorphs (form I, II, III, and IV) from organic solvents were characterized by scanning electron microscope (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and powder X-ray diffraction (PXRD). A feasible LC-M

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Surov, Artem O., Katarzyna A. Solanko, Andrew D. Bond, Annette Bauer-Brandl, and German L. Perlovich. "Polymorphism of felodipine co-crystals with 4,4′-bipyridine." CrystEngComm 16, no. 29 (2014): 6603–11. http://dx.doi.org/10.1039/c4ce00756e.

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The calcium-channel blocking agent felodipine forms co-crystals with 4,4′-bipyridine with 1 : 1 and 2 : 1 molar ratios. The co-crystal with 1 : 1 molar ratio exists in two polymorphic forms. The co-crystals polymorphism was investigated by X-ray diffraction, DSC, solution calorimetry and Hirshfeld surfaces analysis.

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Zhou, Xin-Bo, Jian-Rong Zhu, Jian-Ming Gu, and Xiu-Rong Hu. "A new polymorph of the gastrokinetic drug cisapride monohydrate." Acta Crystallographica Section C Structural Chemistry 74, no. 6 (2018): 690–95. http://dx.doi.org/10.1107/s2053229618006836.

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Cisapride monohydrate (systematic name: 4-amino-5-chloro-N-{(3RS,4SR)-1-[3-(4-fluorophenoxy)propyl]-3-methoxypiperidin-4-yl}-2-methoxybenzamide monohydrate), C23H29ClFN3O4·H2O, is a nondopamine-blocking gastrokinetic drug. A new polymorph of cisapride monohydrate has been reported nearly three decades after the report of its first known crystal structure [Collin et al. (1989). J. Mol. Struct. 214, 159–175]. The second polymorph is also monoclinic, but with different unit-cell parameters. A comparison of both polymorphic forms shows that the difference is thus not in the molecular conformation

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Shishkina, Svitlana V., Irina S. Konovalova, Svitlana S. Kovalenko, Lyudmila L. Nikolaeva, Natalya D. Bunyatyan, and Sergiy M. Kovalenko. "Conformational polymorphs of 3-cyclopropyl-5-(3-methyl-[1,2,4]triazolo[4,3-a]pyridin-7-yl)-1,2,4-oxadiazole." Acta Crystallographica Section C Structural Chemistry 77, no. 1 (2021): 20–28. http://dx.doi.org/10.1107/s2053229620015508.

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The dipharmacophore compound 3-cyclopropyl-5-(3-methyl-[1,2,4]triazolo[4,3-a]pyridin-7-yl)-1,2,4-oxadiazole, C12H11N5O, was studied on the assumption of its potential biological activity. Two polymorphic forms differ in both their molecular and crystal structures. The monoclinic polymorphic form was crystallized from more volatile solvents and contains a conformer with a higher relative energy. The basic molecule forms an abundance of interactions with relatively close energies. The orthorhombic polymorph was crystallized very slowly from isoamyl alcohol and contains a conformer with a much lo

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