scholarly journals Assembling the Puzzle of Taxifolin Polymorphism

Molecules ◽  
2020 ◽  
Vol 25 (22) ◽  
pp. 5437
Author(s):  
Roman P. Terekhov ◽  
Irina A. Selivanova ◽  
Nonna A. Tyukavkina ◽  
Igor R. Ilyasov ◽  
Anastasiya K. Zhevlakova ◽  
...  
Keyword(s):  
Crystal Engineering ◽  
Solid Phase ◽  
Active Pharmaceutical Ingredients ◽  
Amorphous Substance ◽  
X Ray ◽  
Pharmaceutical Ingredients ◽  
Solid States ◽  
Polymorphic Modifications ◽  
Xrpd Patterns ◽  
Scanning Electron

A large amount of the current literature dedicated to solid states of active pharmaceutical ingredients (APIs) pays special attention to polymorphism of flavonoids. Taxifolin (also known as dihydroquercetin) is an example of a typical flavonoid. Some new forms of taxifolin have been reported previously, however it is still unclear whether they represent polymorphic modifications. In this paper, we tried to answer the question about the taxifolin polymorphism. Taxifolin microtubes and taxifolin microspheres were synthesized from raw taxifolin API using several methods of crystal engineering. All forms were described with the help of spectral methods, scanning electron microscopy (SEM), X-ray powder diffraction (XRPD), and thermal analysis (TA). SEM reveals that the morphology of the solid phase is very specific for each sample. Although XRPD patterns of raw taxifolin and microtubes look similar, their TA profiles differ significantly. At the same time, raw taxifolin and microspheres have nearly identical thermograms, while XRPD shows that the former is a crystalline and the latter is an amorphous substance. Only the use of complex analyses allowed us to put the puzzle together and to confirm the polymorphism of taxifolin. This article demonstrates that taxifolin microtubes are a pseudopolymorphic modification of raw taxifolin.

scholarly journals Assay and physicochemical characterization of the antiparasitic albendazole

2012 ◽  
Vol 48 (2) ◽  
pp. 281-290 ◽  
Author(s):  
Noely Camila Tavares Cavalcanti ◽  
Giovana Damasceno Sousa ◽  
Maria Alice Maciel Tabosa ◽  
José Lamartine Soares Sobrinho ◽  
Leila Bastos Leal ◽  
...  
Keyword(s):  
Physicochemical Characterization ◽  
Analytical Techniques ◽  
Assay Method ◽  
Active Pharmaceutical Ingredients ◽  
X Ray Diffraction ◽  
Melting Points ◽  
X Ray ◽  
Pharmaceutical Ingredients ◽  
Complementary Techniques

The aim of this study was to characterize three batches of albendazole by pharmacopeial and complementary analytical techniques in order to establish more detailed specifications for the development of pharmaceutical forms. The ABZ01, ABZ02, and ABZ03 batches had melting points of 208 ºC, 208 ºC, and 209 ºC, respectively. X-ray diffraction revealed that all three batches showed crystalline behavior and the absence of polymorphism. Scanning electron microscopy showed that all the samples were crystals of different sizes with a strong tendency to aggregate. The samples were insoluble in water (5.07, 4.27, and 4.52 mg mL-1, respectively) and very slightly soluble in 0.1 M HCl (55.10, 56.90, and 61.70 mg mL-1, respectively) and additionally showed purities within the range specified by the Brazilian Pharmacopoeia 5th edition (F. Bras. V; 98% to 102%). The pharmacopeial assay method was not reproducible and some changes were necessary. The method was validated and showed to be selective, specific, linear, robust, precise, and accurate. From this characterization, we concluded that pharmacopeial techniques alone are not able to detect subtle differences in active pharmaceutical ingredients; therefore, the use of other complementary techniques is required to ensure strict quality control in the pharmaceutical industry.

Study on the Properties of Doped La in BaBi4Ti4O15 Ceramic

2007 ◽  
Vol 26-28 ◽  
pp. 243-246
Author(s):  
Xing Hua Yang ◽  
Jin Liang Huang ◽  
Xiao Wang ◽  
Chun Wei Cui
Keyword(s):  
Crystal Structure ◽  
Grain Size ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Sintering Temperature ◽  
Solid Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lanthanum Content ◽  
Scanning Electron

BaBi4-xLaxTi4O15 (BBLT) ceramics were prepared by conventional solid phase sintering ceramics processing technology. The crystal structure and the microstructure were detected by X-ray diffraction (XRD) and scanning electron microscope (SEM). The XRD analyses show that La3+ ions doping did not change the crystal structure of BBT ceramics. The sintering temperature increased from 1120°C to 1150°C with increasing Lanthanum content from 0 to 0.5, but it widened the sintering temperature range from 20°C to 50°C and refined the grain size of the BBT ceramic. Additionally, polarization treatment was performed and finally piezoelectric property was measured. As a result, the piezoelectric constant d33 of the 0.1at.% doped BBLT ceramics reached its highest value about 22pc/N at polarizing electric field of 8kV/mm and polarizing temperature of 120°C for 30min.

CO-CRYSTALLIZATION: TECHNIQUE FOR IMPROVEMENT OF PHARMACEUTICAL PROPERTIES

INDIAN DRUGS ◽  
2016 ◽  
Vol 53 (09) ◽  
pp. 5-11
Author(s):  
S. S Pekamwar ◽  
◽  
D. D. Gadade ◽  
G. K. Kale
Keyword(s):  
Crystal Engineering ◽  
Solid Dispersions ◽  
Physicochemical Characteristics ◽  
Potential Effect ◽  
Drug Formulation ◽  
Intrinsic Activity ◽  
Active Pharmaceutical Ingredients ◽  
Pharmaceutical Ingredients ◽  
Physical Form ◽  
Pharmaceutical Properties

Physicochemical characteristics of active pharmaceutical compounds, including solubility and flow properties, are crucial in the development of drug formulation. The physical form of compound and formulation has potential effect on biopharmaceutical parameters of the drug. The crystal engineering approach can be employed for modification of physicochemical properties of the active pharmaceutical ingredients whilst maintaining the intrinsic activity of the drug molecule. This article covers the advantages of co-crystals over salts, solvates (hydrates), solid dispersions and polymorphs, mechanism of formation of co-crystals, methods of preparation of co-crystals and application of co-crystals to modify physicochemical characteristics of active pharmaceutical ingredients along with case studies.

scholarly journals Cocrystal Formation through Solid-State Reaction between Ibuprofen and Nicotinamide Revealed Using THz and IR Spectroscopy with Multivariate Analysis

Crystals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 760
Author(s):  
Sae Ishihara ◽  
Yusuke Hattori ◽  
Makoto Otsuka ◽  
Tetsuo Sasaki
Keyword(s):  
Ir Spectroscopy ◽  
Solid Phase ◽  
Time Dependent ◽  
Multivariate Curve Resolution ◽  
Thz Spectroscopy ◽  
Water Molecules ◽  
Active Pharmaceutical Ingredients ◽  
Curve Resolution ◽  
Pharmaceutical Ingredients ◽  
Solid Phase Reactions

Cocrystallisation can enhance the solubility and bioavailability of active pharmaceutical ingredients (APIs); this method may be applied to improve the availability of materials that were previously considered unsuitable. Terahertz (THz) spectroscopy provides clear, substance-specific fingerprint spectra; the transparency of the THz wave allows us to probe inside a sample to identify medicinal materials. In this study, THz and infrared (IR) spectroscopy were used to characterise cocrystallisation in solid-phase reactions between ibuprofen and nicotinamide. Multivariate curve resolution with alternating least squares (MCR-ALS) was applied to both time-dependent THz and IR spectra to identify the intermolecular interactions between these cocrystallising species. The analytical results revealed cocrystal formation through a two-step reaction, in which the steps were dominated by thermal energy and water vapour, respectively. We infer that the presence of water molecules significantly lowered the activation energy of cocrystal formation.

Solid-Phase Reaction of Tungsten Thin Films with Polycrystalline Diamond

1994 ◽  
Vol 339 ◽  
Author(s):  
A. Bachli ◽  
J. S. Chen ◽  
R. P. Ruiz ◽  
M-A. Nicolet
Keyword(s):  
Solid Phase ◽  
Polycrystalline Diamond ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
X Ray Diffraction ◽  
Final State ◽  
Thermally Induced ◽  
X Ray ◽  
Sputter Deposited ◽  
Scanning Electron

ABSTRACTThe thermally induced solid-phase reaction of 135 nm thick sputter-deposited W films with polycrystalline CVD-grown diamond substrates is investigated. The samples are annealed in vacuum (5×10/-7 torr) at temperatures between 700 °C and 1100 °C for 1 hour and examined by 2 MeV 4He++ backscattering spectrometry, x-ray diffraction, and scanning electron microscopy.The as-deposited W films contain roughly 5 at.% oxygen. After annealing the samples at 800 °C this oxygen concentration falls below the detection limit of less than 1 %. Incipient W2C phase formation occurs during annealing at 900 °C. The final state, the WC phase, is reached after annealing at 1100 °C.

scholarly journals Molecular architectures of new inorganic lamivudine salts, an anti-HIV drug.

2014 ◽  
Vol 70 (a1) ◽  
pp. C1027-C1027
Author(s):  
Juan Tenorio ◽  
Javier Ellena
Keyword(s):  
Crystal Engineering ◽  
Vibrational Analysis ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Pharmaceutical Ingredients ◽  
Pharmaceutical Form ◽  
Pharmaceutical Properties ◽  
Crystalline Forms ◽  
Ir And Raman ◽  
Anti Hiv

One of the currently goals of the crystal engineering is the improvement of pharmaceutical properties of Active Pharmaceutical Ingredients. Herein is discussed the design of new solid forms of the Lamivudine (3TC), one of the most used and marketed anti-HIV drug. The crystalline forms herein presented correspond to inorganic acid salts: Lamivudine hydrobromide (3TCH+-Br-), hydrogen difluoride (3TCH+-F-HF) and nitrate (3TCH+-NO3-). These new salts crystallized in non-centrossymetric space group P21. The halogenated salts (3TCH+-Br-and 3TCH+-F-HF) exhibited isostructural supramolecular assemblies, similar to the anhydrous salt of lamivudine hydrochloride (3TCH+-Cl-) reported by our research group, and whose equilibrium solubility showed an increase when compared with 3TC pharmaceutical form. [1,2] The main feature of the salt crystalline assemblies is related to the supramolecular ordering of the 3TCH+cationic units, by observing the formation of vacancies between them generated in the [100] direction due to the helical symmetry, so, the anions are localized into the interstices of these vacancies, stabilizing the crystalline assemblies. Meanwhile, the 3TCH+NO3-salt showed a different conformational and supramolecular behavior from that observed in the halogenated ones. Here is observed the formation of helical strands along the b axis, which will be engaging by translational symmetry in the horizontal direction in the [10-1] plane. Therefore, they form zigzag molecular planes which will subsequently be architected in parallel with the [10-1] direction. In addition, it was used for this study X-ray powder diffraction (XRDP), vibrational analysis: Infrared (IR) and Raman spectroscopy, and thermal analysis: differential scanning calorimetry (DSC), thermogravimetry (TG) and hot-stage microscopy. Comparison of the structural properties of these salts with some forms already reported (e.g. 3TCH+-Cl-) allows to infer some possible pharmaceutical properties.

scholarly journals Evolution of Free Volumes in Polycrystalline BaGa2O4 Ceramics Doped with Eu3+ Ions

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1515
Author(s):  
Halyna Klym ◽  
Ivan Karbovnyk ◽  
Andriy Luchechko ◽  
Yuriy Kostiv ◽  
Viktorija Pankratova ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Phase Composition ◽  
Grain Boundaries ◽  
Solid Phase ◽  
X Ray Diffraction ◽  
Spectroscopy Technique ◽  
X Ray ◽  
Positron Annihilation Lifetime ◽  
Scanning Electron

BaGa2O4 ceramics doped with Eu3+ ions (1, 3 and 4 mol.%) were obtained by solid-phase sintering. The phase composition and microstructural features of ceramics were investigated using X-ray diffraction and scanning electron microscopy in comparison with energy-dispersive methods. Here, it is shown that undoped and Eu3+-doped BaGa2O4 ceramics are characterized by a developed structure of grains, grain boundaries and pores. Additional phases are mainly localized near grain boundaries creating additional defects. The evolution of defect-related extended free volumes in BaGa2O4 ceramics due to the increase in the content of Eu3+ ions was studied using the positron annihilation lifetime spectroscopy technique. It is established that the increase in the number of Eu3+ ions in the basic BaGa2O4 matrix leads to the agglomeration of free-volume defects with their subsequent fragmentation. The presence of Eu3+ ions results in the expansion of nanosized pores and an increase in their number with their future fragmentation.

Dispersive solid phase extraction of copper and lead from water and lichen samples with an activated carbon@Fe/Mn/O composite derived from sucrose-based activated carbon

2019 ◽  
Vol 11 (41) ◽  
pp. 5311-5319 ◽  
Author(s):  
Veysel Berkdemir ◽  
Şerife Tokalıoğlu ◽  
Süleyman Yıldız ◽  
Şaban Patat
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Activated Carbon ◽  
Zeta Potential ◽  
Solid Phase ◽  
Phase Extraction ◽  
Dispersive Solid Phase Extraction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

In this study, an activated carbon@Fe/Mn/O composite was synthesized and characterized by X-ray diffraction, scanning electron microscopy coupled with energy dispersive X-ray spectroscopy, Brunauer, Emmett, and Teller surface area and zeta potential measurements.

scholarly journals Aspartate/asparagine-β-hydroxylase: a high-throughput mass spectrometric assay for discovery of small molecule inhibitors

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Lennart Brewitz ◽  
Anthony Tumber ◽  
Inga Pfeffer ◽  
Michael A. McDonough ◽  
Christopher J. Schofield
Keyword(s):  
Small Molecules ◽  
Small Molecule ◽  
High Throughput ◽  
Solid Phase ◽  
Hypoxia Inducible Factor ◽  
Active Pharmaceutical Ingredients ◽  
Inhibition Assay ◽  
Pharmaceutical Ingredients ◽  
Epidermal Growth ◽  
Good Signal

AbstractThe human 2-oxoglutarate dependent oxygenase aspartate/asparagine-β-hydroxylase (AspH) catalyses the hydroxylation of Asp/Asn-residues in epidermal growth factor-like domains (EGFDs). AspH is upregulated on the surface of malign cancer cells; increased AspH levels correlate with tumour invasiveness. Due to a lack of efficient assays to monitor the activity of isolated AspH, there are few reports of studies aimed at identifying small-molecule AspH inhibitors. Recently, it was reported that AspH substrates have a non-canonical EGFD disulfide pattern. Here we report that a stable synthetic thioether mimic of AspH substrates can be employed in solid phase extraction mass spectrometry based high-throughput AspH inhibition assays which are of excellent robustness, as indicated by high Z’-factors and good signal-to-noise/background ratios. The AspH inhibition assay was applied to screen approximately 1500 bioactive small-molecules, including natural products and active pharmaceutical ingredients of approved human therapeutics. Potent AspH inhibitors were identified from both compound classes. Our AspH inhibition assay should enable the development of potent and selective small-molecule AspH inhibitors and contribute towards the development of safer inhibitors for other 2OG oxygenases, e.g. screens of the hypoxia-inducible factor prolyl-hydroxylase inhibitors revealed that vadadustat inhibits AspH with moderate potency.

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