Voxelotor (VOX), a small-molecule BCS class-II drug,
is used for the treatment
of sickle cell disease. The USFDA granted accelerated approval for
this drug molecule in 2019 as a first-in-class medication. A novel
1:0.5 cocrystal of voxelotor with a pharmaceutically acceptable coformer,
oxalic acid (OA), has been identified to ameliorate the aqueous solubility
of the drug and characterized using various solid-state techniques
such as PXRD, DSC, TGA, and Fourier transform infrared spectroscopy.
Further, single crystals were successfully generated for both the
voxelotor-OA cocrystal (VOX-OA) and the VOX free base (Form-II) to
have structural insights. Crystal structure analysis has been performed
to understand the torsional/interplanar angles, hydrogen bonds, packing
of the molecules, and other weak interactions for both the forms (cocrystal
and Form-II) using single-crystal XRD studies. In addition, Hirshfeld
surface analysis has been performed to delineate the intermolecular
interactions quantitatively. The equilibrium solubility revealed that
VOX-OA exhibited superior performances compared to VOX Form-II (marketed
form) at pH conditions of 4.5 and 6.8. The hemi-OA cocrystal of voxelotor
is stable enough under formulation stress conditions such as drying,
milling, 10 ton pressure, open exposure, and humidity exposure. The
cocrystal was found to be stable in the excipient compatibility study
as no polymorphic transformation of the cocrystal is observed.