{"title":"Differentiation of puerarin chelate from salt by phase solubility test.","authors":"Yuanfeng Wei, Xin Chen, Runxue Ding, Jingwen Zhang, Hui Chen, Junxiao Zhu, Jianjun Zhang, Peiya Shen","doi":"10.1016/j.xphs.2024.10.007","DOIUrl":null,"url":null,"abstract":"<p><p>Different from salt, metal chelate is a novel state of drug constructed by more separate coordinate bonds to form a chelating circle. Due to their composition similarity, it is hard to distinguish them except identifying ionic bond (i.e., salt) or coordinate bond (i.e., chelate) in the single crystal structure. In this study, sodium chelate (CDCC No: 1865670) and lithium salt (CDCC No: 2161617) of puerarin (PUE) was prepared. In addition to difference in single crystal structure, it was found that they showed totally different phase solubility behaviors: lithium salt demonstrated a typical inverse proportion curve as other common salts, while sodium chelate exhibited disordered scatters. However, when incorporating the unit PUE-Na complex in solution state and complexation constant K<sub>11</sub> in chemical equation, the scatters in phase solubility diagram of chelate could be well fitted and the value of K<sub>11</sub> was dramatically higher with orders of magnitude than the dissociation constant K<sub>c</sub>; while processing phase solubility curve of lithium salt by incorporating complex item, it could not well match the curve at all. PUE sodium chelate is more likely to be a weak electrolyte with partial dissociation, while PUE lithium salt acted as a strong electrolyte with complete dissociation. The phase solubility test would be served as a surrogate tool for differentiation of chelates from salts when single crystal was not available.</p>","PeriodicalId":16741,"journal":{"name":"Journal of pharmaceutical sciences","volume":null,"pages":null},"PeriodicalIF":3.7000,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of pharmaceutical sciences","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1016/j.xphs.2024.10.007","RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, MEDICINAL","Score":null,"Total":0}
引用次数: 0
Abstract
Different from salt, metal chelate is a novel state of drug constructed by more separate coordinate bonds to form a chelating circle. Due to their composition similarity, it is hard to distinguish them except identifying ionic bond (i.e., salt) or coordinate bond (i.e., chelate) in the single crystal structure. In this study, sodium chelate (CDCC No: 1865670) and lithium salt (CDCC No: 2161617) of puerarin (PUE) was prepared. In addition to difference in single crystal structure, it was found that they showed totally different phase solubility behaviors: lithium salt demonstrated a typical inverse proportion curve as other common salts, while sodium chelate exhibited disordered scatters. However, when incorporating the unit PUE-Na complex in solution state and complexation constant K11 in chemical equation, the scatters in phase solubility diagram of chelate could be well fitted and the value of K11 was dramatically higher with orders of magnitude than the dissociation constant Kc; while processing phase solubility curve of lithium salt by incorporating complex item, it could not well match the curve at all. PUE sodium chelate is more likely to be a weak electrolyte with partial dissociation, while PUE lithium salt acted as a strong electrolyte with complete dissociation. The phase solubility test would be served as a surrogate tool for differentiation of chelates from salts when single crystal was not available.
期刊介绍:
The Journal of Pharmaceutical Sciences will publish original research papers, original research notes, invited topical reviews (including Minireviews), and editorial commentary and news. The area of focus shall be concepts in basic pharmaceutical science and such topics as chemical processing of pharmaceuticals, including crystallization, lyophilization, chemical stability of drugs, pharmacokinetics, biopharmaceutics, pharmacodynamics, pro-drug developments, metabolic disposition of bioactive agents, dosage form design, protein-peptide chemistry and biotechnology specifically as these relate to pharmaceutical technology, and targeted drug delivery.