Thermal behavior of naproxen and ketoprofen nonsteroidal anti-inflammatory drugs
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Thermal behavior of naproxen and ketoprofen nonsteroidal anti‑inflammatory drugs R. S. Medeiros1 · A. P. G. Ferreira1 · E. T. G. Cavalheiro1 Received: 29 August 2019 / Accepted: 24 January 2020 © Akadémiai Kiadó, Budapest, Hungary 2020
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 °C (∆Hfus = 31.6 kJ mol−1; ∆Sfus = 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 °C (∆Hfus=28.4 kJ mol−1, ∆Sfus = 76.9 J K−1 mol−1) was observed, without crystallization or cooling. Keywords Naproxen · Ketoprofen · Anti-inflammatory · Evolved gas analysis · Thermal behavior
Introduction Naproxen (NAP) ((+)-(S)-2-(6-methoxynaphthalen-2-yl) propionic acid) and ketoprofen (KET) (RS)-(2-(3-benzoylphenyl)propionic acid) are nonsteroidal anti-inflammatory (NSAIDs) drugs. Both present anti-inflammatory, anti-thermic and analgesic action, related to the inhibition of the cyclo-oxygenase
enzymes, COX1 and COX2, which catalyze the production of prostaglandins, physiologically active lipids, that induce inflammation. Moreover, they are used in the treatment of rheumatic diseases such as rheumatoid arthritis, osteoarthritis, ankylosing spondylitis, gout, menstrual cramps, pains and inflammations in skeletal muscle tissues [1, 2]. Structural formulas of naproxen and ketoprofen are:
Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10973-020-09389-1) contains supplementary material, which is available to authorized users. * E. T. G. Cavalheiro [email protected] 1
Instituto de Química de São Carlos, Universidade de São Paulo, Av. Trabalhador São‑carlense, 400, São Carlos, SP 13566‑590, Brazil
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In a general sense, the combination of thermal analysis with complementary spectroscopic techniques allows evaluation of the thermal behavior of a variety of materials, including drugs [3], making it possible to study thermal decomposition, thermal stability, solid-state reactions, purity evaluation, physical transformations, polymorphic transitions, melting point, crystallization, evolution of gases and many other transformati
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