title: Influence of atomic bonds on the properties of the laxative drug sodium picosulphate.
abstract: In this work, the influence of the different S═O, S-O, N⋯H, O⋯H, Na⋯O bonds present in the structures of the powerful laxative drug, sodium picosulphate in gas and aqueous solution phases were studied combining the density functional theory (DFT) calculations with the experimental available infrared,1H NMR and UV-visible spectra. The structural, topological, electronic and vibrational properties were investigated in both media by using the hybrid B3LYP/6-31G* method and the integral equation formalism variant polarised continuum model (IEFPCM). Here, the characteristics of the S═O, S-O, N⋯H, O⋯H, Na⋯O bonds were completely revealed by using atomic charges, natural bond orbital (NBO) and atoms in molecules (AIM) studies. The infrared,1H NMR,13C NMR and UV-visible spectra are in reasonable concordance with those experimental available in the literature. The vibrational analysis of sodium picosulphate was performed consideringC3Vsymmetries for both SO42-groups and the complete assignments of the 126 vibration modes were reported in gas phase and aqueous solution together with their corresponding force fields. In addition, the reactivities of sodium picosulfate increase in solution due to their ionic characteristic which probably justifies their behaviour as a stimulant cathartic and their easy metabolic conversion, as reported in the literature.
authors.affiliation: SST, Servicio sanitario della Toscana, Azienda USL 9 di Grosseto, Via Cimabue, 109, 58100 Grosseto, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Romani
authors.affiliation: Cátedra de Química General, Instituto de Química Inorgánica, Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Ayacucho 471,(4000), San Miguel de Tucumán, Tucumán, Argentina.
authors.forename: Isabel Salas
authors.initials: IS
authors.lastname: Tonello
authors.affiliation: Cátedra de Química General, Instituto de Química Inorgánica, Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Ayacucho 471,(4000), San Miguel de Tucumán, Tucumán, Argentina.
authors.forename: Silvia Antonia
authors.initials: SA
authors.lastname: Brandán
keywords: Inorganic chemistry; Pharmaceutical science; Theoretical chemistry