Novel cocrystals of brexpiprazole with improved solubility

Brexpiprazole (BPZ) is a typical antipsychotic drug used for the treatment of schizophrenia and depression. It is classified under BCS class-II with low aqueous solubility and high intestinal permeability. In the present investigation, we reported novel solid forms of brexpiprazole with acid coformers such as glutaric acid (GLU), fumaric acid (FUM), malonic acid (MAL) and succinic acid (SUC) via solvent drop grinding method. All the cocrystals were completely characterized by PXRD (Powder X-ray Diffraction), DSC (Differential Scanning Calorimetry) and FTIR (Fourier Transform Infrared Spectroscopy). The crystal structure is determined for malonic acid cocrystal by single-crystal X-ray diffraction method. The crystal structure revealed that the cocrystal crystallized in the triclinic crystal system with space group P-1 and the malonic acid molecules are sandwiched by brexpiprazole molecules. The solubility studies for brexpiprazole and cocrystals are established in 0.05 M acetate buffer with pH 4.3 at 25 ± 2 °C. Among all solid forms BPZ:FUM cocrystal shown 2.6 times higher solubility than parent drug whereas other cocrystals such as BPZ:GLU, BPZ:SUC and BPZ:MAL improved by 1.77, 1.59 and 1.37 times.