Crystal structure of an apremilast ethanol hemisolvate hemihydrate solvatomorph.

The title compound, C22H24N2O7S·0.5C2H5OH·0.5H2O {systematic name: (S)-4-acetamido-2-[1-(3-eth-oxy-4-meth-oxy-phen-yl)-2-(methyl-sulfon-yl)eth-yl]iso-indo-line-1,3-dione ethanol hemisolvate hemihydrate}, is a novel solvatomorph of apremilast (AP), which is an inhibitor of phosphodiesterase 4 (PDE4) and is indicated for the treatment of adult patients with active psoriatic arthritis. The asymmetric unit contains one mol-ecule of AP and disordered mol-ecules of ethanol and water, both with half occupancy. The dihedral angle between the planes of the phenyl ring and the iso-indole ring is 67.9 (2)°. Extensive intra- and inter-molecular hydrogen bonds help to stabilize the mol-ecular conformation and sustain the crystal packing.