(S)-α-Ethyl-2-oxo-1-pyrrolidineacetamide (trade name levetiracetam), a derivative of piracetam, is used clinically as an add-on treatment for partial-onset seizures. In this study, we report the solid-state structure of a new drug co-crystal produced from levetiracetam and 3,5-dinitrosalicylic acid through cooling crystallization. This compound was further characterized by infrared spectroscopy, powder X-ray diffraction, and single-crystal X-ray diffraction. The new co-crystals show a 1:1 stoichiometry and crystallize in the monoclinic system, space group P21, with cell parameters: a = 9.7709(3) Å, b = 6.2202(2) Å, c = 14.7280(4) Å, α = 90°, β = 96.0340(10)°, γ = 90°, V = 890.16(5) Å3, and Z = 2. It is identified that hydrogen bonds are the main interactions between levetiracetam and 3,5-dinitrosalicylic acid, and the contribution of each hydrogen bond in maintaining the stability of the crystal structure was also quantified using Hirshfeld surface analysis.

In this work, we developed an X-ray powder diffractometer system equipped with six solid-state detectors and used it to perform ab initio structure determination from the powder diffraction pattern data obtained for a caffeine–oxalic acid co-crystal. The crystal structure obtained from the powder diffraction data was consistent with the previously solved single-crystal structure (Trask reference), although slightly larger (by about 2%). The co-crystallization of pharmaceutically active molecules can modulate their physical properties such as solubility, stability, and bioavailability. For the investigation of pharmaceutical complexes, the ability to visualize molecular interactions such as hydrogen bonding would be very helpful toward understanding their physical properties. Given the rate at which the high-throughput screening of pharmaceutical complexes has grown, an analogous high-volume, high-resolution X-ray powder diffraction technique with high-throughput data collection ability would be useful. We also solved the crystal structures of an inorganic complex and metal organic framework, zinc acetate dihydrate and CPL-1, in order to demonstrate the performance of our new diffractometer system.