Synthesis, crystal structure, and solubility study of a supramolecular assembly cocrystal formed by levofloxacin and nicotinic acid

A novel chemical structure named pharmaceutical cocrystal was synthesized with the purpose to enhance the solubility of levofloxacin (LVFX). Nicotinic acid (NA) was selected as cocrystal coformer (CCF). The cocrystal was successfully obtained by solvent evaporation method combined with ultrasonic technology. The crystal structure of LVFX-NA is triclinic with a P1 space group, unit cell parameters a = 7.1392 angstrom, b = 10.0188 angstrom, c = 17.5394 angstrom, alpha=86.109 (7), beta=86.082 (6), gamma =73.809 (7), z = 2, R1=0.0518, omega R2=0.1425. The supramolecular structure of LVFX-NA is mainly controlled by O-H N and C-H center dot center dot center dot O intermolecular hydrogen bond. Moreover, intramolecular hydrogen bonds C-H center dot center dot center dot F have also been found in the cocrystal structural units. The obtained cocrystal exhibits unique properties of thermoanalysis, Fourier transform infrared (FT-IR) spectrum and X-ray powder diffraction (PXRD) spectrum, demonstrated the new formed crystal material. Equilibrium solubility measurement revealed that LVFX-NA exhibited improved aqueous solubility, that is 5.02 times higher than the original LVFX. (C) 2021 Published by Elsevier B.V.

Automated summary

A novel chemical structure called pharmaceutical cocrystal was synthesized to enhance the solubility of levofloxacin (LVFX), with nicotinic acid (NA) chosen as the cocrystal coformer (CCF). The cocrystal, with a triclinic crystal structure, demonstrated improved aqueous solubility compared to the original LVFX, being 5.02 times higher.