Crystal Structure and Solid-State Properties of 3,4-Diaminopyridine Dihydrogen Phosphate and Their Comparison with Other Diaminopyridine Salts

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• 作者：Nathalie Mah茅 ; B茅atrice Nicola茂 ; Hassan Allouchi ; Maria Barrio ; Bernard Do ; Ren茅 C茅olin ; Josep-Lluis Tamarit ; Ivo B. Rietveld
• 刊名：Crystal Growth & Design
• 出版年：2013
• 出版时间：February 6, 2013
• 年：2013
• 卷：13
• 期：2
• 页码：708-715
• 全文大小：504K
• 年卷期：v.13,no.2(February 6, 2013)
• ISSN：1528-7505

文摘

3,4-Diaminopyridine is an active pharmaceutical ingredient for the treatment of Lambert鈥揈aton myasthenic syndrome (LEMS). It is 3,4-diaminopyridine dihydrogen phosphate that has become the active ingredient of choice. As part of a larger study for the development of this drug, solid-state studies have been carried out. At room temperature, the crystals are monoclinic (C2/c). Dihydrogen phosphate anions H₂PO₄^{鈥?/sup> form infinite chains parallel to the b axis, and these chains can be considered as macroanions (H₂PO₄)鈭? The organic cations form hydrogen bonds with the macroanions bridging them together. A negative thermal expansion is observed along the [103] direction in the crystal, which coincides with the direction of chains of interchanging anions and cations. The crystal packing shows similarities with the hydrogen tartrate salt as illustrated by a Hirshfeld surface analysis. This phosphate and this tartrate salt are also the two diaminopyridine salts that have been selected for therapeutic use because of their appropriate physical properties.}