title: Synthesis and preliminary characterization of sulfamethazine-theophylline co-crystal.
abstract: Co-crystals containing active pharmaceutical ingredients (APIs) represent a new type of pharmaceutical materials. In this work, sulfamethazine (STH) and theophylline (TP) were employed as the co-crystal formers. Neat cogrinding, solvent-drop cogrinding and slow evaporation were applied to synthesize the sulfamethazine-theophylline co-crystal (hereafter STH-TP co-crystal). The co-crystalline phase was characterized by DSC, TGA, Raman, PXRD, and dynamic vapor sorption (DVS) techniques. The STH-TP co-crystal structure was determined from single crystal X-ray diffraction data. The results show that, the STH-TP co-crystal, obtained in a 2:1 molar ratio of sulfamethazine and theophylline only by slow evaporation, possesses unique thermal, spectroscopic, and X-ray diffraction properties. Besides, in the STH-TP co-crystal, the sulfamethazine molecules form a dimer through the intermolecular hydrogen bonding (O ... H -- N), and two intermolecular hydrogen bonds (O ... H -- N and N ... H -- N) keep the theophylline attached the dimer.
authors.affiliation: School of Chemical & Material Engineering, Jiangnan University, Wuxi 214122, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Lu
authors.forename: Sohrab
authors.initials: S
authors.lastname: Rohani
mesh_terms: D000890:Anti-Infective Agents / Q000737:chemistry*; D001993:Bronchodilator Agents / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D013418:Sulfamethazine / Q000737:chemistry*; D013806:Theophylline / Q000737:chemistry*
chemical_list: D000890:Anti-Infective Agents; D001993:Bronchodilator Agents; D013418:Sulfamethazine; D013806:Theophylline