ABSTRACT
Piroxicam has polymorphism. Different crystalline forms can exhibit different physicochemical properties and biological activities. Analysis of the intermolecular interactions is essential to reveal the formation mechanism and differences of polymorphs. In this paper, Hirshfeld surface analysis and semi-empirical methods were used to calculate and analyze the intermolecular interactions in seven polymorphic forms of piroxicam. The results show that the Hirshfeld surface analysis method can clearly and intuitively reveal the intermolecular interactions, among which H…H, O…H/H…O and N…H/H…N interactions account for 95% of the total energy. There are differences in the proportion and distribution of the forces of different crystal forms. The energy calculation shows that the lattice energy of the hydrate is significantly lower than that of the anhydrous forms, and in the specific energy distribution, the contribution of the dispersion force is the most prominent. Further interaction energy analysis was found that within the distance of 3.8 Å from the center of the piroxicam molecule, different crystalline forms of piroxicam molecule have different interaction energies with surrounding molecules.
ABSTRACT
Four salts of ticagrelor, ticagrelor-3,5-dinitrobenzoic acid, ticagrelor-pyrazinamide, ticagrelor-D-proline and ticagrelor-L-proline were prepared by solvent suspension and liquid-assisted grinding to improve the solubility of ticagrelor. The compounds were characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry, nuclear magnetic resonance spectroscopy, elemental analysis, and the intermolecular salt-bonding forces were analyzed. The equilibrium solubility of salts and pure drug in hydrochloride buffer pH 1.2 and phosphate buffer pH 6.8 were measured by high-performance liquid chromatography. Ticagrelor was salted with 3,5-dinitrobenzoic acid, pyrazinamide, D-proline, L-proline all in a stoichiometric ratio of 1∶1; with the exception of ticagrelor-D-proline, the solubility of the other three salts provided significantly improved solubility in hydrochloride buffer pH 1.2, and the equilibrium solubility of ticagrelor-3,5-dinitrobenzoic acid was increased by approximately 1.7 folds as compared to pure drug. Salt-forming technology is convenient and can improve the solubility of ticagrelor.
ABSTRACT
The powder X-ray diffraction Fourier fingerprint pattern technique was used to develop a new quantitation method for the analysis of andrographolide and dehydroandrographolide. And the high performance liquid chromatography method was used to evaluate the quantity of andrographolide and dehydroandrographolide. The relationship of diffraction peak intensity and content of andrographolide and dehydroandrographolide was investigated. The powder X-ray diffraction Fourier fingerprint pattern analysis technique can be used to evaluate the quantity of andrographolide and dehydroandrographolide in the herb simultaneously.
Subject(s)
Andrographis , Chemistry , Chromatography, High Pressure Liquid , Diterpenes , Drugs, Chinese Herbal , Fourier Analysis , Plant Components, Aerial , Chemistry , Plants, Medicinal , Chemistry , Powders , X-Ray Diffraction , MethodsABSTRACT
<p><b>OBJECTIVE</b>To study the selective isolation of a single chemical component from volatile oil of Fructus foeniculi by inclucion method.</p><p><b>METHOD</b>The host molecule was selected and a single chemical component isolated from volatile oil by the host-guest recognition.</p><p><b>RESULT</b>X-ray single crystal analysis showed that 1,1,6,6-tetraphenylhexa-2, 4-diyne-1, 6-diol could successfully include 4-[1-propenyl] benzaldehyde from volatile oil of Fructus foeniculi.</p><p><b>CONCLUSION</b>The host-guest inclusion technology can be used to isolate a single component selectively from mixture.</p>
Subject(s)
Crystallization , Crystallography, X-Ray , Methods , Foeniculum , Chemistry , Molecular Conformation , Oils, Volatile , Chemistry , Plants, Medicinal , Chemistry , Seeds , ChemistryABSTRACT
<p><b>OBJECTIVE</b>To demonstrate the chemical constituents of Alyxia sinensis.</p><p><b>METHOD</b>The constituents were isolated by column chromatography and identified by advanced physical and spectral analysis.</p><p><b>RESULT</b>Eight compounds have been isolated and elucidated as bauereny acetate(18), scopletin(19), liriodendrin(20), pinoresinol-di-O-beta-D-glucopyranoside(21), daucosterol(22), flaxetin(23), esculin(24), aseculin(25).</p><p><b>CONCLUSION</b>These compounds were found from the plant for the first time, and compound 20,21,23-25 were found from Alyxiae genis for the first time, and compound 18 is firstly been isolated from natural source.</p>