scholarly journals Structural Characterization of Co-Crystals of Chlordiazepoxide with p-Aminobenzoic Acid and Lorazepam with Nicotinamide by DSC, X-ray Diffraction, FTIR and Raman Spectroscopy

Pharmaceutics ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 648
Author(s):  
Patrycja Garbacz ◽  
Dominik Paukszta ◽  
Artur Sikorski ◽  
Marek Wesolowski
Keyword(s):  
Raman Spectroscopy ◽  
Water Solubility ◽  
Proton Exchange ◽  
Aminobenzoic Acid ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Pharmaceutical Ingredients ◽  
Crystallization Procedure ◽  
Ftir And Raman Spectroscopy

The low water solubility of benzodiazepines seriously affects their bioavailability and, in consequence, their biological activity. Since co-crystallization has been found to be a promising way to modify undesirable properties in active pharmaceutical ingredients, the objective of this study was to prepare co-crystals of two benzodiazepines, chlordiazepoxide and lorazepam. Using different co-crystallization procedures, slurry evaporation and liquid-assisted grinding, co-crystals of chlordiazepoxide with p-aminobenzoic acid and lorazepam with nicotinamide were prepared for the first time. Confirmation that co-crystals were obtained was achieved through a comparison of the data acquired for both co-crystals using differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), Fourier-transform infrared (FTIR) and Raman spectroscopy, with comparisons acquired for the physical mixtures of both benzodiazepines and coformers. The compatibility of PXRD patterns of both benzodiazepines co-crystals with those contained in the base Powder Diffraction File (PDF-4+) suggests that new crystal structures were indeed created under the co-crystallization procedure. Single-crystal X-ray diffraction revealed that a chlordiazepoxide co-crystal with p-aminobenzoic acid and a lorazepam co-crystal with nicotinamide crystallized in the monoclinic P21/n and P21/c space group, respectively, with one molecule of benzodiazepine and one of coformer in the asymmetric unit. FTIR and Raman spectroscopy corroborated that benzodiazepine and coformer are linked by a hydrogen bond without proton exchange. Furthermore, a DSC study revealed that single endothermic DSC peaks assigned to the melting of co-crystals differ slightly depending on the co-crystallization procedures and solvent used, as well as differing from those of starting components.

Salts of purine alkaloids caffeine and theobromine with 2,6-dihydroxybenzoic acid as coformer: structural, theoretical, thermal and spectroscopic studies

2021 ◽  
Vol 77 (11) ◽  
Author(s):  
Mateusz Gołdyn ◽  
Anna Komasa ◽  
Mateusz Pawlaczyk ◽  
Aneta Lewandowska ◽  
Elżbieta Bartoszak-Adamska
Keyword(s):  
Hydrogen Bonds ◽  
Water Solubility ◽  
Theoretical Calculations ◽  
Spectroscopic Studies ◽  
X Ray Diffraction ◽  
Dihydroxybenzoic Acid ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Purine Alkaloids ◽  
Vis Spectroscopy

The study of various forms of pharmaceutical substances with specific physicochemical properties suitable for putting them on the market is one of the elements of research in the pharmaceutical industry. A large proportion of active pharmaceutical ingredients (APIs) occur in the salt form. The use of an acidic coformer with a given structure and a suitable pK a value towards purine alkaloids containing a basic imidazole N atom can lead to salt formation. In this work, 2,6-dihydroxybenzoic acid (26DHBA) was used for cocrystallization of theobromine (TBR) and caffeine (CAF). Two novel salts, namely, theobrominium 2,6-dihydroxybenzoate, C7H9N4O2 +·C7H5O4 − (I), and caffeinium 2,6-dihydroxybenzoate, C8H11N4O2 +·C7H5O4 − (II), were synthesized. Both salts were obtained independently by slow evaporation from solution, by neat grinding and also by microwave-assisted slurry cocrystallization. Powder X-ray diffraction measurements proved the formation of the new substances. Single-crystal X-ray diffraction studies confirmed proton transfer between the given alkaloid and 26DHBA, and the formation of N—H...O hydrogen bonds in both I and II. Unlike the caffeine cations in II, the theobromine cations in I are paired by noncovalent N—H...O=C interactions and a cyclic array is observed. As expected, the two hydroxy groups in the 26DHBA anion in both salts are involved in two intramolecular O—H...O hydrogen bonds. C—H...O and π–π interactions further stabilize the crystal structures of both compounds. Steady-state UV–Vis spectroscopy showed changes in the water solubility of xanthines after ionizable complex formation. The obtained salts I and II were also characterized by theoretical calculations, Fourier-transform IR spectroscopy (FT–IR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and elemental analysis.

scholarly journals Evaluation of Thermal-Induced Polymorphic Transformation on Desloratadine and Desloratadine-Benzoic Acid Salt

2020 ◽  
Vol 26 (4) ◽  
pp. 399-405
Author(s):  
Ahmad Ainurofiq ◽  
Rachmat Mauludin ◽  
Diky Mudhakir ◽  
Sundani Nurono Soewandhi
Keyword(s):  
Melting Point ◽  
Benzoic Acid ◽  
Polymorphic Transformation ◽  
Heating Process ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Pharmaceutical Ingredients ◽  
Physicochemical Changes ◽  
Transformation Methods

Background: Active pharmaceutical ingredients face a challenge in manufacturing due to adverse physicomechanical properties. Desloratadine (DES) form I exhibits poor mechanical behavior through the formation of capping during the tableting process. Salt formation from DES and benzoic acid (BA) has been observed to resolve poor mechanical properties. However, the ability to withstand heat from the manufacturing process should be implemented in DES and DES-BA salt. The aim of this study was to determine the differences between thermal treatment results on DES and DES-BA salt and whether it causes them to undergo polymorphic transformation. Methods: Salt was crystallized between DES and BA using the solvent evaporation method. DES and DES-BA salt were heated at 110°C, 159°C (melting point of DES), 181°C (melting point of DES-BA), and 190°C. Following this, characterization was performed using differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and solubility testing. Results: Polymorphic transformation caused by heat occurred in DES, but not in DES-BA salt. The transformation of DES was induced by the effect of heating, which changed polymorph I to a mixture of polymorph I and III at 110°C, to polymorph II at 159°C, and to a mixture of polymorph I, II, and III at 190°C. Under 190oC, DES-BA is still stable and did not undergo a polymorphic transformation. However, at 190oC, decomposition started to occur, which implied decreased solubility, which did not occur in DES. Conclusion: The heating process did not cause DES-BA salt to undergo a polymorphic transformation. However, it caused decomposition at 190oC. DES underwent a polymorphic transformation when exposed to the same condition without decomposition. This provided information to always pay attention to temperature during manufacturing processes that include DES or DES-BA salt to avoid physicochemical changes.

Exothermic behaviour of aluminium and graphene as a fuel in Fe2O3 based nanothermite

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Priya Thakur ◽  
Vimal Sharma ◽  
Nagesh Thakur
Keyword(s):  
Raman Spectroscopy ◽  
Energy Release ◽  
Graphene Sheets ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Layer Graphene ◽  
Physical Mixing ◽  
Field Emission Electron Microscopy ◽  
Fesem Micrographs

Abstract The main frontier of this research is to study the influence of multi-layer graphene (MLG) and aluminium as a fuel in Al/Fe2O3 and MLG/Fe2O3 nanothermites, fabricated by physical mixing and ultrasonication techniques. To study the structural and energy release properties, prepared samples were characterized by XRD, FESEM, EDS, FTIR, Raman spectroscopy and DSC. The X-ray diffraction (XRD) technique showed that all the phases remain intact during the synthesis. Field emission electron microscopy (FESEM) micrographs displayed the surface morphology of the samples, and besides this, energy dispersive spectroscopy (EDS) was used to check the elemental composition of samples. Raman spectroscopy revealed that the ultrasonication waves did not deteriorate the aromatic structure of graphene sheets. Fourier transform infrared spectroscopy (FTIR) spectra were used to observe the information about various functional groups present in the thermite samples. The exothermic energy released by the thermite reaction in both the samples was investigated by differential scanning calorimetry (DSC) and the observed values of energy release for Al/Fe2O3 and MLG/Fe2O3 are 215 J/g and 1640 J/g.

Low-temperature phase transition in glycine–glutaric acid co-crystals studied by single-crystal X-ray diffraction, Raman spectroscopy and differential scanning calorimetry

2012 ◽  
Vol 68 (3) ◽  
pp. 287-296 ◽  
Author(s):  
Boris A. Zakharov ◽  
Evgeniy A. Losev ◽  
Boris A. Kolesov ◽  
Valeri A. Drebushchak ◽  
Elena V. Boldyreva
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Raman Spectroscopy ◽  
Single Crystal ◽  
Glutaric Acid ◽  
Group Symmetry ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray

The occurrence of a first-order reversible phase transition in glycine–glutaric acid co-crystals at 220–230 K has been confirmed by three different techniques – single-crystal X-ray diffraction, polarized Raman spectroscopy and differential scanning calorimetry. The most interesting feature of this phase transition is that every second glutaric acid molecule changes its conformation, and this fact results in the space-group symmetry change from P21/c to P\bar 1. The topology of the hydrogen-bonded motifs remains almost the same and hydrogen bonds do not switch to other atoms, although the hydrogen bond lengths do change and some of the bonds become inequivalent.

Characterization of New Cocrystals by Raman Spectroscopy, Powder X-ray Diffraction, Differential Scanning Calorimetry, and Transmission Raman Spectroscopy

2010 ◽  
Vol 10 (5) ◽  
pp. 2360-2371 ◽  
Author(s):  
M. A. Elbagerma ◽  
H. G. M. Edwards ◽  
T. Munshi ◽  
M. D. Hargreaves ◽  
Pavel Matousek ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Raman Spectroscopy ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Raman

scholarly journals Two Novel Palbociclib-Resorcinol and Palbociclib-Orcinol Cocrystals with Enhanced Solubility and Dissolution Rate

Pharmaceutics ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 23
Author(s):  
Chenxin Duan ◽  
Wenwen Liu ◽  
Yunwen Tao ◽  
Feifei Liang ◽  
Yanming Chen ◽  
...  
Keyword(s):  
Water Solubility ◽  
Cancer Drug ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Dissolution Rates ◽  
Intrinsic Dissolution ◽  
X Ray ◽  
Enhanced Solubility

Palbociclib (PAL) is an effective anti-breast cancer drug, but its use has been partly restricted due to poor bioavailability (resulting from extremely low water solubility) and serious adverse reactions. In this study, two cocrystals of PAL with resorcinol (RES) or orcinol (ORC) were prepared by evaporation crystallization to enhance their solubility. The cocrystals were characterized by single crystal X-ray diffraction, Hirshfeld surface analysis, powder X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, Fourier transform infrared and scanning electron microscopy. The intrinsic dissolution rates of the PAL cocrystals were determined in three different dissolution media (pH 1.0, pH 4.5 and pH 6.8), and both cocrystals showed improved dissolution rates at pH 1.0 and pH 6.8 in comparison to the parent drug. In addition, the cocrystals increased the solubility of PAL at pH 6.8 by 2–3 times and showed good stabilities in both the accelerated stability testing and stress testing. The PAL-RES cocrystal also exhibited an improved relative bioavailability (1.24 times) than PAL in vivo pharmacokinetics in rats. Moreover, the in vitro cytotoxicity assay of PAL-RES showed an increased IC50 value for normal cells, suggesting a better biosafety profile than PAL. Co-crystallization may represent a promising strategy for improving the physicochemical properties of PAL with better pharmacokinetics.

scholarly journals Improvement of the optical and photocatalytic properties of ZnAl2O4: 1% La3+, x% Pb2+ nanoparticles synthesized by citrate sol-gel route

2021 ◽  
Author(s):  
Hichem Filali ◽  
Nahman Boukheit ◽  
Rafika Bouhroum ◽  
Wassila Chekirou ◽  
Ahcène Karaali
Keyword(s):  
Raman Spectroscopy ◽  
Single Phase ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Constant Amount ◽  
Pure Zinc ◽  
Characterization Methods ◽  
X Ray ◽  
Gel Technique

Abstract Samples of pure zinc aluminate (ZnAl2O4) and doped both with lead (Pb2+) at different ratios (0, 0.5, 1, 1.5, 2 and 2.5% mol) and a constant amount of lanthanum (La: 1% mol), were prepared by the citrate sol-gel technique, and then annealed at 900°C for 2h. In order to study the structural, optical and thermal properties; different characterization methods were used, such as: powder X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), differential scanning calorimetry (DSC), TGA, Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. The Analyzes by XRD revealed the presence of the cubic single phase ZnAl2O4 for all samples, with a crystallites size between 19 and 25 nm. These results were confirmed using FTIR, Raman spectroscopy and SEM. Also, photocatalytic study for different samples of ZnAl2O4 shows that they can be used like as photocatalyst and good adsorbents for degradation of Hexamethyl crystallized violet dye in aqueous solution.

Thermodynamic and Structural Properties of Mev Ion Beam Amorphized Silicon

1989 ◽  
Vol 157 ◽  
Author(s):  
S. Roorda ◽  
W.C. Sinke ◽  
J.M. Poate ◽  
D.C. Jacobson ◽  
P. Fuoss ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Raman Spectroscopy ◽  
Structural Properties ◽  
Atomic Structure ◽  
Structural Relaxation ◽  
Ion Beam ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Amorphous Si

ABSTRACTThermodynamic and structural properties of amorphous Si (a-Si), prepared by MeV 28Si+-ion implantation are investigated by differential scanning calorimetry, Raman spectroscopy and X-ray diffraction. The influence of thermal annealing below 500 °C on a-Si is investigated with these different probes. The observed changes result from structural relaxation. Raman spectroscopy and X-ray diffraction show that structural relaxation is accompanied by changes in the average atomic structure.

scholarly journals Pharmaceutical Salts of Enrofloxacin with Organic Acids

Crystals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 646
Author(s):  
Hong Pang ◽  
Yu-Bin Sun ◽  
Jun-Wen Zhou ◽  
Meng-Juan Xie ◽  
Hao Lin ◽  
...  
Keyword(s):  
High Performance ◽  
Water Solubility ◽  
Antibacterial Drug ◽  
Mixed Solution ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Organic Salts ◽  
X Ray ◽  
Poorly Soluble ◽  
Pharmaceutical Properties

Enrofloxacin is a poorly soluble antibacterial drug of the fluoroquinolones class used in veterinary medicine. The main purpose of this work was to investigate the structural and pharmaceutical properties of new enrofloxacin salts. Enrofloxacin anhydrate and its organic salts with tartaric acid, nicotinic acid and suberic acid formed as pure crystalline anhydrous solids. All the crystals were grown from a mixed solution by slow evaporation at room temperature. These products were then characterized by field-emission scanning electron microscopy, powder X-ray diffraction, Fourier transform infrared spectroscopy and differential scanning calorimetry. Further, X-ray single crystal diffraction analysis was used to study the crystal structure. The intermolecular interactions and packing arrangements in the crystal structures were studied, and the solubility of these salts in water was determined using high-performance liquid chromatography. The results show that the new salts of enrofloxacin developed in this study exhibited excellent water solubility.

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