A new febuxostat imidazolium salt hydrate: Synthesis, crystal structure, solubility, and dissolution study

Energy framework and solubility: a new predictive model in the evaluation of the structure–property relationship of pharmaceutical solid forms

Crystal structures with lower interaction energy tend to present higher aqueous solubility.

Cocrystallization of Febuxostat with Pyridine Coformers: Crystal Structural and Physicochemical Properties Analysis

Drug cocrystals and salts have promising applications for modulating the physicochemical properties and solubility of pharmaceuticals. In this study, a cocrystal and two salts of febuxostat (FEB) with pyridine nitrogen coformers, including 4, 4′-bipyridine (BIP), 3-aminopyridine (3AP) and 4-hydroxypyridine (4HP), were designed to improve the solubility of FEB. The single-crystal structures were elucidated, and their physical and chemical properties were investigated by IR, PXRD, and DSC. In addition, drug-related properties, including the solubility and powder dissolution rate were assessed. The solubility and powder dissolution studies showed that the FEB-BIP cocrystal and FEB-3AP salt have superior dissolution compared to FEB.

Improving the Solubility of Aripiprazole by Multicomponent Crystallization

Aripiprazole (ARI) is a third-generation antipsychotic with few side effects but a poor solubility. Salt formation, as one common form of multicomponent crystals, is an effective strategy to improve pharmacokinetic profiles. In this work, a new ARI salt with adipic acid (ADI) and its acetone hemisolvate were obtained successfully, along with a known ARI salt with salicylic acid (SAL). Their comprehensive characterizations were conducted using X-ray diffraction and differential scanning calorimetry. The crystal structures of the ARI-ADI salt acetone hemisolvate and ARI-SAL salt were elucidated by single-crystal X-ray diffraction for the first time, demonstrating the proton transfer from a carboxyl group of acid to ARI piperazine. Theoretical calculations were also performed on weak interactions. Moreover, comparative studies on pharmaceutical properties, including powder hygroscopicity, stability, solubility, and the intrinsic dissolution rate, were carried out. The results indicated that the solubility and intrinsic dissolution rate of the ARI-ADI salt and its acetone hemisolvate significantly improved, clearly outperforming that of the ARI-SAL salt and the untreated ARI. The study presented one potential alternative salt of aripiprazole and provided a potential strategy to increase the solubility of poorly water-soluble drugs.

Febuxostat ethanol monosolvate

The title compound, 2-(3-cyano-4-iso-but-oxyphen-yl)-4-methyl-1,3-thia-zole-5-car-b-oxy-lic acid ethanol monosolvate, C16H16N2O3S·C2H6O, (I), displays inter-molecular O-H⋯O and O-H⋯N bonds in which the carboxyl group of the febuxostat mol-ecule and the hydroxyl group of the ethanol mol-ecule serve as hydrogen-bond donor sites. These inter-actions result in a helical hydrogen-bonded chain structure. The title structure is isostructural with a previously reported methanol analogue.

Structure of Imidazolium-N-phthalolylglycinate Salt Hydrate: Combined Experimental and Quantum Chemical Calculations Studies

An organic supramolecular salt hydrate (imidazolium:N-phthalolylglycinate:H2O; IM+-NPG−-HYD) has been examined for its charge-transfer (CT) characteristics. Accordingly, IM+–NPG−–HYD has been characterized thoroughly using various spectroscopic techniques. Combined experimental and quantum chemical studies, along with wave function analysis, were performed to study the non-covalent interactions and their role in CT in the supramolecular salt hydrate. Notably, IM+–NPG−–HYD crystalizes in two configurations (A and B), both of which are held together via non-covalent interactions to result in a three-dimensional CT supramolecular assembly. The through-space CT occurs from NPG– (donor) to IM+ (acceptor), and this was mediated via non-covalent forces. We demonstrated the role of π–π stacking interactions (mixed-stacking donor-acceptor interactions) in the presence of charge-assisted hydrogen bonds in the regulation of CT properties in the self-assembly of the IM+–NPG−–HYD salt hydrate.

Synthesis and solid-state characterization of diclofenac imidazolium monohydrate: an imidazolium pharmaceutical ionic liquid

A new imidazolium hydrated salt (DCF–IMI–H₂O) of the nonsteroidal anti-inflammatory drug diclofenac (DCF) was synthesized by solvent evaporation.