Kinetic parameters for thermal decomposition of supramolecular polymers derived from flunixin-meglumine adducts
Meglumine, (2R,3R,4R,5S)-6-methylaminohexane-1,2,3,4,5-pentol, is a carbohydrate derived from sorbitol in which the hydroxyl group in position one is replaced by a methylamine group. It forms binary adducts with substances having carboxyl groups, which have in common the presence of hydrogen bonding as the main force in the stabilization of these species. During melting, adducts of meglumine with flunixin (2-[[2-methyl-3-(trifluoromethyl)phenyl]amino]pyridine-3-carboxylic acid) polymerize or self-assemble in amorphous supramolecular structures with molecular weights around 2.0 × 105 kDa. DSC curves, in a first heating, show isomorphic transitions where the last one at 137 °C for the flunixin-meglumine adduct originated the supramolecular amorphous polymers with glass transition around 49.5 °C. The kinetic parameters for the thermal decomposition step of the polymers were determined by the Capela-Ribeiro non-linear isoconversional method. From data for the TG curves in nitrogen atmosphere and heating rates of 5, 10, 15, and 20 °C min−1, the E α and B α terms could be determined and, consequently, the pre-exponential factor, Aα, as well as the kinetic model, g(α).
KeywordsSupramolecular polymers Flunixin-meglumine Adducts Non-isothermal kinetics Thermal decomposition
The authors acknowledge the FACTE—Fundação de Apoio à Ciência Tecnologia e Educação and CAPES—Coordenação de Aperfeiçoamento de Pessoal de Nível Superior for financial support.
- 1.Armitage BJ. Therapeutic agent. The Boots Company PLC (England). US 4501727, 26 Feb 1985.Google Scholar
- 2.Veronesi PA. Water soluble salts of an NSAID either meglumine/glucamine. Therapicon SRL (Italy). US 4748174, 31 May 1988.Google Scholar
- 3.Motola S. Acid addition salt of ibupofren and meglumine. American Home Products Corporation (United States). US 5028625, 2 Jul 1991.Google Scholar
- 4.Cao XJ, Sun CR, Pan YJ. The complex of flunixin and meglumine. Acta Cryst. 2003;59:1471–3.Google Scholar
- 9.Hulbert SF. Models for solid-state decompositions in powdered compacts. J Br Ceram Soc. 1969;6:11–20.Google Scholar
- 10.Bamdford CH, Tipper CFH, editors. Comprehensive chemical kinetics: reactions in the solid state, vol. 22. Amsterdam: Elsevier; 1980.Google Scholar
- 11.Sestak J. Thermal analysis: thermophysical properties of solid their measurements and theoretical thermal analysis. Amsterdam: Elsevier; 1984. (Part D).Google Scholar
- 12.Gawey AK, Brown ME. Thermal decomposition of ionic solids. Amsterdam: Elsevier; 1999.Google Scholar