Next Article in Journal
A Standard Structure for Bile Acids and Derivatives
Next Article in Special Issue
Drug‑Drug and Drug‑Nutraceutical Cocrystal/Salt as Alternative Medicine for Combination Therapy: A Crystal Engineering Approach
Previous Article in Journal
The Carbonate Platform Model and Reservoirs’ Origins of the Callovian-Oxfordian Stage in the Amu Darya Basin, Turkmenistan
Previous Article in Special Issue
Structural Characterization of Febuxostat/l-Pyroglutamic Acid Cocrystal Using Solid-State 13C-NMR and Investigational Study of Its Water Solubility
Article Menu
Issue 2 (February) cover image

Export Article

Open AccessArticle
Crystals 2018, 8(2), 85;

Febuxostat-Minoxidil Salt Solvates: Crystal Structures, Characterization, Interconversion and Solubility Performance

School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China
Université Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, 15 rue J-A de Baïf, 75205 Paris CEDEX 13, France
MOE Joint International Research Laboratory of Synthetic Biology and Medicine, South China University of Technology, Guangzhou 510006, China
Author to whom correspondence should be addressed.
Received: 5 January 2018 / Revised: 2 February 2018 / Accepted: 2 February 2018 / Published: 5 February 2018
(This article belongs to the Special Issue Novel Pharmaceutical Cocrystals and Their Applications)
Full-Text   |   PDF [8325 KB, uploaded 5 February 2018]   |  


Three febuxostat-minoxidil salt solvates with acetone (ACE), tetrahydrofuran (THF) and isopropanol (IPA) are synthesized by solvent-assisted grinding and characterized by infrared (IR), nuclear magnetic resonance (1H-NMR), single crystal and powder X-ray diffraction (PXRD), thermogravimetry (TG) and differential scanning calorimetry (DSC). These febuxostat-minoxidil salt solvates feature isostructural with the same stoichiometries (1:1:1 molecule ratio). The proton transfers from the carboxylic group of febuxostat (FEB) to imino N atom of minoxidil (MIN), which forms the motif with combined R 2 2 (9) R 4 2 (8) R 2 2 (9) graph set in the three solvates. The solvents occupy the different positions related to the motif, which results in the apparent differences in PXRD patterns before/after desolvation although they are isostructures. The FEB-MIN·THF was more thermostable than FEB-MIN·ACE and FEB-MIN·IPA relative to solvent removal from DSC patterns, which is different from the results from the solvent-exchange experiments in chemical kinetics. All three salt solvates exhibit increased equilibrium solubility compared to FEB in aqueous medium. View Full-Text
Keywords: febuxostat; minoxidil; salt solvates; crystal structure febuxostat; minoxidil; salt solvates; crystal structure

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Supplementary material


Share & Cite This Article

MDPI and ACS Style

Li, L.-Y.; Du, R.-K.; Du, Y.-L.; Zhang, C.-J.; Guan, S.; Dong, C.-Z.; Zhang, L. Febuxostat-Minoxidil Salt Solvates: Crystal Structures, Characterization, Interconversion and Solubility Performance. Crystals 2018, 8, 85.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Crystals EISSN 2073-4352 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top