Thermal behavior of naproxen and ketoprofen nonsteroidal anti-inflammatory drugs

Author(s)

Medeiros, R. S. ; Ferreira, A. P. G. ; Cavalheiro, E. T. G.

• Document type: Journal article
• Source: JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY; v. 142, n. 2, p. 11-pg., 2020-02-08.

Abstract

Nonsteroidal anti-inflammatory drugs naproxen (NAP) ((+)-(S)-2-(6-methoxynaphthalen-2-yl) propionic acid) and ketoprofen (KET) (RS)-(2-(3-benzoylphenyl)-propionic acid) were investigated by thermoanalytical techniques (TG/DTG/DTA, DSC and hot-stage microscopy) and evolved gas analysis (TG-FTIR) for evaluating their thermal behavior. In air, TG curve of NAP presented one mass loss step followed by the burning of carbonaceous material, with final residue of 1.5%, while in nitrogen, a single mass loss step was observed. After melting, if the sample is submitted to an isotherm it evaporates. According to DSC curve, NAP melts at 153.5 degrees C ( increment H-fus = 31.6 kJ mol(-1); increment S-fus = 73.5 J K-1 mol(-1)) and recrystallizes in the cooling step. These events were confirmed by hot-stage microscopy. TG-FTIR studies revealed that NAP decomposes by releasing 2-methoxynaphthalene and propionic acid. Ketoprofen TG curves in both atmospheres presented a single mass loss. When the sample was kept under isotherm, after melting, it evaporated. From DSC data, the melting at 93.3 degrees C ( increment H-fus=28.4 kJ mol(-1), increment S-fus = 76.9 J K-1 mol(-1)) was observed, without crystallization or cooling. (AU)

• FAPESP's process: 17/04211-7 - Development of inks based on metalic nanoparticles and polymers for the preparation of conventional and printed electrodes
• Grantee: Éder Tadeu Gomes Cavalheiro
• Support Opportunities: Regular Research Grants