No abstract

In the present work, the thermal behavior of Lornoxicam drug was studied under oxidizing (air) and pyrolysis (N2) atmospheres using simultaneous thermogravimetry and differential scanning calorimetry (TG-DSC), differential scanning calorimetry (DSC), Hot Stage Microscopy (HSM) and Evolved Gas Analysis (EGA) in the form of thermogravimetry coupled to infrared spectroscopy (TG-FTIR) and mass spectrometry (TG-MS). The thermal degradation product formed at different temperatures were examined using liquid chromatography coupled to mass spectrometry (LC-MS) and Powder X-Ray Diffraction (PXRD). The thermal study showed that the drug does not melt, partially amorphized on heating, it is thermally stable to 205 °C and undergoes thermal decomposition in two overlapping mass loss steps. Furthermore, the DSC and MS techniques suggest that thermal degradation processes are very complex, which occur with the release of gaseous products HCN, SO2, COS, CO2, N2O and CO and formation of three intermediate in the thermal residue.

Lornoxicam metal complexes [M(Lor)2(OH2)2]•nH2O, where M represents the bivalent transition metals (Mn(II) to Zn(II)), Lor is Lornoxicam ligand and n = 2.0 or 2.5 were synthesized. The compounds were characterized by elemental analysis (EA), powder X-ray diffraction (PXRD), infrared spectroscopy (FTIR), simultaneous thermogravimetry and differential scanning calorimetry (TG-DSC) under oxidizing and pyrolysis conditions, differential scanning calorimetry (DSC), hot-stage microscopy (HSM) and evolved gas analysis (EGA) by coupled hot-stage microscopy (HSM-MS) and Fourier transform infrared (TG−FTIR). Regardless of the atmosphere, the thermal stability and thermal behavior up to the first two mass loss steps of the anhydrous compound were similar, only differing significantly in the last steps. The main gaseous products released * Corresponding author.

Solid-state LnL 3 •nH 2 O complexes, where Ln stands for trivalent lanthanides (Tb to Lu) or yttrium(III) and L is oxamate (NH 2 COCO 2-), have been synthesized. The characterization of the complexes was performed by using elemental analysis (EA), complexometric titration with EDTA, thermoanalytical techniques such as simultaneous thermogravimetry and differential scanning calorimetry (TG-DSC), evolved gas analysis (TG-FTIR), infrared spectroscopy (IR) and powder X-ray diffraction (XRPD). The results provided information about thermal behavior, crystallinity, stoichiometry, coordination sites, as well as the products released during thermal degradation of the complexes studied. Theoretical calculation of yttrium oxamate, as representative of all complexes was performed using density functional theory (DFT) for studying the molecular structure and vibrational spectrum of the investigated molecule in the ground state. The optimized geometrical parameters and theoretical vibrational spectrum obtained by DFT calculations are in good agreement with the experimental results.