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21. Synthesis, Characterization, and Analysis of Probenecid and Pyridine Compound Salts.

Author

Zhang, Menglong, Hou, Xinyu, Yu, Fuhai, Zhang, Liang, Hou, Baohong, Zhou, Lina, Xie, Chuang, Wu, Songgu, and Chen, Wei

Subjects
MELTING points, MOLECULAR conformation, ELECTRIC potential, INTERMOLECULAR interactions, SURFACE potential, DRUG solubility
Abstract

This study aimed to address the issue of the low solubility in the model drug probenecid (PRO) and its impact on bioavailability. Two salts of probenecid (PRO), 4-aminopyridine (4AMP), and 4-dimethylaminopyridine (4DAP) were synthesized and characterized by PXRD, DSC, TGA, FTIR, and SEM. The crystal structures of the two salts were determined by SCXRD, demonstrating that the two salts exhibited different hydrogen bond networks, stacking modes, and molecular conformations of PRO. The solubility of PRO and its salts in a phosphate-buffered solution (pH = 6.8) at 37 °C was determined, the results showed that the solubility of PRO salts increased to 142.83 and 7.75 times of the raw drug, respectively. Accelerated stability experiments (40 °C, 75% RH) showed that the salts had good phase stability over 8 weeks. Subsequently, Hirshfeld surface (HS), atom in molecules (AIM), and independent gradient model (IGM) were employed for the assessment of intermolecular interactions. The analyses of salt-forming sites and principles were conducted using molecular electrostatic potential surfaces (MEPs) and pKa rules. The lattice energy (EL) and hydration-free energy (EHF) of PRO and its salts were calculated, and the relationships between these parameters and melting points and the solubility changes were analyzed. [ABSTRACT FROM AUTHOR]

Published
2024
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31. Effects of Different Flotation Agents on the Nucleation and Growth of Potassium Chloride.

Author

Wang, Guangle, Bian, Xiao, Shang, Zeren, Dong, Weibing, Zhang, Yi, and Wu, Songgu

Subjects
POTASSIUM chloride, DISCONTINUOUS precipitation, FLOTATION, HOMOGENEOUS nucleation, HETEROGENOUS nucleation, SUPERSATURATION
Abstract

The flotation agent is an important collector in the production of potassium chloride and is brought into the crystallization stage with the reflux of the mother liquor. Octadecylamine Hydrochloride (ODA), 1-Dodecylamine Hydrochloride (DAH) and Sodium 1-dodecanesulfonate (SDS) were selected to study their effect on the nucleation of potassium chloride. Focused Beam Reflectance Measurement was used to collect the nucleation-induced periods of KCl in the presence of flotation agents at different supersaturations. Then, empirical equations, classical nucleation theory and growth mechanism equations were employed for data analysis. It was found that the presence of flotation agents increased the nucleation sequence m, and m(ODA) > m(SDS) > m(DAH) > m(H2O). In addition, the interfacial energy data obtained using classical nucleation theory suggest that the flotation agents used in our paper promoted the homogeneous nucleation of KCl (reduced from 5.3934 mJ·m−2 to 5.1434 mJ·m−2) and inhibited the heterogeneous nucleation of KCl (increased from 2.8054 mJ·m−2 to 3.6004 mJ·m−2). This investigation also revealed that the growth of potassium chloride was consistent with the 2D nucleation-mediated growth mechanism, and the addition of flotation agent did not change the growth mechanism of potassium chloride. Finally, the particle size distribution results were exactly consistent with the order of nucleation order m. The study of nucleation kinetics and growth mechanisms of different flotation agents on potassium chloride can provide guidance for optimizing the production process of potassium chloride and developing new flotation agents. [ABSTRACT FROM AUTHOR]

Published
2023
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36. Asparagine endopeptidase-targeted Ultrasound-responsive Nanobubbles Alleviate Tau Cleavage and Amyloid-β Deposition in an Alzheimer's Disease Model

Author

Mi, Xue, primary, Du, Haiqiao, additional, Guo, Xinmeng, additional, Wu, Yan, additional, Shen, Long, additional, Luo, Yukun, additional, Wang, Dekun, additional, Su, Qiuyue, additional, Xiang, Rong, additional, Yue, Shijing, additional, Wu, Songgu, additional, Gong, Junbo, additional, Yang, Zhuo, additional, Zhang, Yuying, additional, and Tan, Xiaoyue, additional

Published
2022
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