Next Article in Journal
Enhanced Electrocaloric Effect in 0.73Pb(Mg1/3Nb2/3)O3-0.27PbTiO3 Single Crystals via Direct Measurement
Previous Article in Journal
2D Layer Arrangement of Solely [HS-HS] or [LS-LS] Molecules in the [HS-LS] State of a Dinuclear Fe(II) Spin Crossover Complex
Previous Article in Special Issue
35Cl NQR Relaxation of the Molecular Ferroelectric 5,6-Dichloro-2-Methylbenzimidazole with Hydrogen-Bonded Molecular Chain
Review

Nuclear Quadrupole Resonance (NQR)—A Useful Spectroscopic Tool in Pharmacy for the Study of Polymorphism

1
Institute of Mathematics, Physics and Mechanics, 1000 Ljubljana, Slovenia
2
Faculty of Pharmacy, University of Ljubljana, 1000 Ljubljana, Slovenia
3
Faculty of Electrical Engineering, University of Ljubljana, 1000 Ljubljana, Slovenia
4
Jožef Stefan Institute, 1000 Ljubljana, Slovenia
*
Author to whom correspondence should be addressed.
Deceased.
Crystals 2020, 10(6), 450; https://doi.org/10.3390/cryst10060450
Received: 30 January 2020 / Revised: 1 April 2020 / Accepted: 22 May 2020 / Published: 31 May 2020
(This article belongs to the Special Issue NQR of Polymorphic Crystals)
Nuclear Quadrupole Resonance (NQR) spectroscopy has been known for 70 years. It is suitable for the study of measured (poly)crystalline chemical compounds containing quadrupole nuclei (nuclei with spin I ≥ 1) where the characteristic NQR frequencies represent the fingerprints of these compounds. In several cases, 14N NQR can distinguish between the polymorphic crystalline phases of active pharmaceutical ingredients (APIs). In order to further stimulate 14N NQR studies, we review here several results of API polymorphism studies obtained in Ljubljana laboratories: (a) In sulfanilamide, a clear distinction between three known polymorphs (α, β, γ) was demonstrated. (b) In famotidine, the full spectra of all seven different nitrogen positions were measured; two polymorphs were distinguished. (c) In piroxicam, the 14N NQR data helped in confirming the new polymorphic form V. (d) The compaction pressure in the tablet production of paracetamol, which is connected with linewidth change, can be used to distinguish between producers of paracetamol. We established that paracetamol in the tablets of six different manufacturers can be identified by 14N NQR linewidth. (e) Finally, in order to get an extremely sensitive 14N NQR spectrometer, the optical detection of the 14N NQR signal is mentioned. View Full-Text
Keywords: NQR; Nuclear Quadrupole Resonance spectroscopy; 14N NQR and relaxation; drug polymorphism; crystal polymorphism; X-ray powder diffraction (XRPD); powder mixture quantification; NQR with optically pumped magnetometer NQR; Nuclear Quadrupole Resonance spectroscopy; 14N NQR and relaxation; drug polymorphism; crystal polymorphism; X-ray powder diffraction (XRPD); powder mixture quantification; NQR with optically pumped magnetometer
Show Figures

Figure 1

MDPI and ACS Style

Trontelj, Z.; Pirnat, J.; Jazbinšek, V.; Lužnik, J.; Srčič, S.; Lavrič, Z.; Beguš, S.; Apih, T.; Žagar, V.; Seliger, J. Nuclear Quadrupole Resonance (NQR)—A Useful Spectroscopic Tool in Pharmacy for the Study of Polymorphism. Crystals 2020, 10, 450. https://doi.org/10.3390/cryst10060450

AMA Style

Trontelj Z, Pirnat J, Jazbinšek V, Lužnik J, Srčič S, Lavrič Z, Beguš S, Apih T, Žagar V, Seliger J. Nuclear Quadrupole Resonance (NQR)—A Useful Spectroscopic Tool in Pharmacy for the Study of Polymorphism. Crystals. 2020; 10(6):450. https://doi.org/10.3390/cryst10060450

Chicago/Turabian Style

Trontelj, Zvonko, Janez Pirnat, Vojko Jazbinšek, Janko Lužnik, Stane Srčič, Zoran Lavrič, Samo Beguš, Tomaž Apih, Veselko Žagar, and Janez Seliger. 2020. "Nuclear Quadrupole Resonance (NQR)—A Useful Spectroscopic Tool in Pharmacy for the Study of Polymorphism" Crystals 10, no. 6: 450. https://doi.org/10.3390/cryst10060450

Find Other Styles
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop