Elucidating the crystal structure of the antimalarial drug (+-)-mefloquine hydrochloride: a tetragonal hydrated species. PRADO, V. M. ; SEICEIRA, R. C. ; PITALUGA JUNIOR, A. ; Andrade-Filho, T. ; ALVES, W. A. ; Rocha, A. R. ; Ferreira, Fabio Furlan . Journal of Applied Crystallography, v. 47, p. 1380-1386, 2014.
Abstract: Albeit widely studied, the structure of the antimalarial drug (±)-mefloquine hydrochloride is still a controversial issue. A combination of X-ray powder diffraction, theoretical calculations and Fourier transform-infrared spectroscopy is used to unambiguously determine the crystal structure of the molecule in its active pharmaceutical ingredient. It is demonstrated that water is incorporated into the structure, leading to a hydrated form and, most importantly, to significant differences in both structure and bonding. Such changes can lead to significant differences in biological activity.