title: Solid-state NMR studies of theophylline co-crystals with dicarboxylic acids.
abstract: In this work, three polycrystalline materials containing co-crystals of theophylline with malonic, maleic, and glutaric acids were studied using (13)C, (15)N and (1)H solid-state NMR and FT-IR spectroscopy. The NMR assignments were supported by gauge including projector augmented waves (GIPAW) calculations of chemical shielding, performed using X-ray determined geometry. The experimental (13)C cross polarization/magic angle spinning (CP/MAS) NMR results and the calculated isotropic chemical shifts were in excellent agreement. A rapid and convenient method for theophylline co-crystals crystal structure analysis has been proposed for co-crystals, which are potentially new APIs.
authors.affiliation: Faculty of Pharmacy, Medical University of Warsaw, Department of Inorganic and Analytical Chemistry, Banacha 1, 02-093 Warsaw, Poland. Electronic address: edyta.pindelska@wum.edu.pl.
authors.forename: Edyta
authors.initials: E
authors.lastname: Pindelska
authors.affiliation: Faculty of Pharmacy, Medical University of Warsaw, Department of Inorganic and Analytical Chemistry, Banacha 1, 02-093 Warsaw, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Sokal
authors.affiliation: Faculty of Pharmacy, Medical University of Warsaw, Department of Physical Chemistry, Banacha 1, 02-093 Warsaw, Poland.
authors.forename: Lukasz
authors.initials: L
authors.lastname: Szeleszczuk
authors.affiliation: Faculty of Pharmacy, Medical University of Warsaw, Department of Physical Chemistry, Banacha 1, 02-093 Warsaw, Poland.
authors.forename: Dariusz Maciej
authors.initials: DM
authors.lastname: Pisklak
authors.affiliation: Faculty of Pharmacy, Medical University of Warsaw, Department of Inorganic and Analytical Chemistry, Banacha 1, 02-093 Warsaw, Poland.
authors.forename: Waclaw
authors.initials: W
authors.lastname: Kolodziejski
mesh_terms: D002626:Chemistry, Pharmaceutical; D003460:Crystallization; D018360:Crystallography, X-Ray; D003998:Dicarboxylic Acids / Q000737:chemistry*; D005977:Glutarates / Q000737:chemistry; D006860:Hydrogen Bonding; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008298:Maleates / Q000737:chemistry; D008314:Malonates / Q000737:chemistry; D015394:Molecular Structure; D017550:Spectroscopy, Fourier Transform Infrared; D013678:Technology, Pharmaceutical / Q000379:methods*; D013806:Theophylline / Q000031:analogs & derivatives / Q000737:chemistry*
chemical_list: D003998:Dicarboxylic Acids; D005977:Glutarates; D008298:Maleates; D008314:Malonates; C030272:maleic acid; C030290:malonic acid; D013806:Theophylline; C035736:glutaric acid
keywords: Co-crystals; GIPAW calculations; Theophylline; ssNMR