title: Molecular modeling and infrared and Raman spectroscopy of the crystal structure of the chiral antiparasitic drug Praziquantel.
abstract: Anthelmintic praziquantel (PZQ) and its molecular and crystal lattice structures were studied by means of atomistic calculations based on empirical interatomic potentials and quantum mechanical methods (DFT). This chiral drug presents several crystal polymorphs due to the enantiomers (either R or S) or the racemic crystal, and different molecular conformations. The relative configurations of the carbonyl groups in PZQ define these conformations that produce different polymorphs. The polarity of these conformers is quite different and their relative population can vary in media with different polarity. Crystal structures of PZQ were studied by infrared and Raman spectroscopy and their spectroscopical properties were calculated by quantum mechanical methods, assigning many of their bands, and finding a good agreement with experimental data.
authors.affiliation: Instituto Andaluz de Ciencias de la Tierra (CSIC-University of Granada), Av. de las Palmeras 4, 18100, Armilla, Granada, Spain.|Department of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of Granada, Campus de Cartuja s/n, 18071, Granada, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Borrego-Sánchez
authors.affiliation: Instituto Andaluz de Ciencias de la Tierra (CSIC-University of Granada), Av. de las Palmeras 4, 18100, Armilla, Granada, Spain.
authors.forename: Alfonso
authors.initials: A
authors.lastname: Hernández-Laguna
authors.affiliation: Instituto Andaluz de Ciencias de la Tierra (CSIC-University of Granada), Av. de las Palmeras 4, 18100, Armilla, Granada, Spain. ignacio.sainz@iact.ugr-csic.es.
authors.forename: C Ignacio
authors.initials: CI
authors.lastname: Sainz-Díaz
mesh_terms: D000977:Antiparasitic Agents / Q000737:chemistry; D003460:Crystallization; D008958:Models, Molecular; D015394:Molecular Structure; D011223:Praziquantel / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D013059:Spectrum Analysis, Raman; D013237:Stereoisomerism
chemical_list: D000977:Antiparasitic Agents; D011223:Praziquantel
keywords: Conformers; DFT calculations; IR spectroscopy; Polymorphism; Praziquantel; Raman spectroscopy