X-Ray diffraction, spectroscopy and thermochemical characterization of the pharmaceutical paroxetine nitrate salt

A comprehensive solid state study of Paroxetine nitrate hydrate, (PRX+·NO3−)H2O, is reported. This salt was characterized by a combination of methods, including Single crystal X-ray diffraction, Thermal analysis, Fourier transform infrared spectroscopy (FTIR) and Solubility measurements. (PRX+·NO3−)H2O crystallizes in the monoclinic C2 space group (Z′ = 1) and its packing was analyzed in details, showing that the main supramolecular motif consists in a C22(4) chain formed by charge-assisted N+-H⋯O− hydrogen bonds. The salt formation and conformation features were also accuracy established via FTIR spectra. In comparison with the pharmaceutical approved (PRX+⋅Cl−)⋅0.5H2O, (PRX+⋅NO3−)⋅H2O showed a decrease of 24 °C in the drug melting peak and a slight reduction in its water solubility value.

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