Febuxostat methanol solvate

Febuxostat solubilization and stabilization approach using solid dispersion method: Synergistic effect of dicalcium phosphate dehydrate and chitosan

Drug solubilization studies are continuously being conducted. Febuxostat (FBX) has a low solubility in water. This study aims to develop a stable FBX-solid dispersion (SD) formulation using a solvent evaporation method. The solubilization strategy of FBX is to develope an optimal FBX-SD formulation by selecting a solubilizer and carrier through the screening method. The final selected solubilizer, macrogol 15 hydroxystearate and polyoxyl 15 hydroxystearate (Kolliphor® HS-15), is widely used in the pharmaceutical industry as a nonionic solubilizing and emulsifying agent and has low toxicity. Especially when commonly used in developing lipophilic drug formulations, it dissolves well in water and ethyl alcohol. The optimal composition ratio of the formulation (SD4) was FBX:HS-15®:granular dicalcium phosphate dehydrate (DCP-D): A synthetic magnesium aluminometasilicate (Neusilin®UFL2):chitosan = 1:3:3:1:1 (w/w) and showed 3.0-, 2.3-, and 1.1-fold higher dissolution (%) of FBX compared to that of the Feburic tab® in pH 1.2 media, distilled water (DW), and pH 6.8 buffer, respectively. Also, in vitro release and in vitro permeability in SD4 formulation showed higher than that of Feburic tab®. Based on its stability over 6 months, it was confirmed that chitosan acted as a stabilizer. Moreover, due to weak intermolecular interactions, FBX in the SD4 formulation was considered to exist in a mixed state of amorphous and crystalline FBX. In conclusion, the improved dissolution (%) and stability of FBX in SD4 formulation were secured through the synergistic effect of excipients.

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.

Crystal structure of vilazodone hydro-chloride methanol monosolvate

In the title compound, C26H28N5O2+·Cl-·CH3OH {systematic name: 4-(2-carbamoyl-1-benzo-furan-5-yl)-1-[4-(5-cyano-1H-indol-3-yl)but-yl]piperazin-1-ium chloride methanol monosolvate}, the protonated piperazine ring adopts a chair conformation. The indole ring plane is nearly perpendicular to the benzo-furan ring system, with a dihedral angle of 85.77 (2)°. In the crystal, the organic cations, Cl- anions and methanol solvent mol-ecules are linked by classical N-H⋯O and N-H⋯Cl hydrogen bonds, and weak C-H⋯O and C-H⋯π inter-actions into a three-dimensional supra-molecular architecture.

Crystal structure of febuxostat-acetic acid (1/1)

The asymmetric unit of the title compound [systematic name: 2-(3-cyano-4-iso­butyl­oxyphen­yl)-4-methyl­thia­zole-5-carb­oxy­lic acid–acetic acid (1/1)], C₁₆H₁₆N₂O₃S·CH₃COOH, contains a febuxostat mol­ecule and an acetic acid mol­ecule. In the febuxostat mol­ecule, the thia­zole ring is nearly coplanar with the benzene ring [dihedral angle = 3.24 (2)°]. In the crystal, the febuxostat and acetic acid mol­ecules are linked by O—H⋯O, O—H⋯N hydrogen bonds and weak C—H⋯O hydrogen bonds, forming supra­molecular chains propagating along the b-axis direction. π–π stacking is observed between nearly parallel thia­zole and benzene rings of adjacent mol­ecules; the centroid-to-centroid distances are 3.8064 (17) and 3.9296 (17) Å.