Preparation of the Ca–diclofenac complex in solid state
The Ca–diclofenac compound was prepared. Thermogravimetry (TG), derivative thermogravimetry (DTG), differential scanning calorimetry (DSC), X-ray diffraction powder patterns, and microscopy analysis were used to characterize this compound. Details concerning the stages of dehydration, transition phase, and thermal decomposition as well as data of the kinetic parameters of these stages have been described here. The kinetic study of these stages was evaluated from several heating rates with a sample mass of 2 and 5 mg in open crucibles under nitrogen atmosphere. The obtained data were evaluated with the isoconversional kinetic method, where the value of activation energy (E a/kJ mol−1) was evaluated in function of the conversion degree (α). The results show that this compound is hygroscopic. The obtained data lead to a dependence on the sample mass, which results in two kinetic behavior patterns.
KeywordsDiclofenac Dehydration Thermal decomposition Kinetic parameters
We express our deepest gratitude to CAPES Foundation, Brazil, for financial support, and IPT—Instituto de Pesquisas Tecnológicas do Estado de São Paulo for TG curves.
- 1.Moser P, Sallmann A, Wiesenbergt I. Synthesis and quantitative structure-activity relationships of diclofenac analogues. J Med Chem. 1990;33:2358–68.Google Scholar
- 4.Konstandinidou M, Kourounakis A, Yiangou M, Hadjipetrou L, Kovala-Demertzi D, Hadjikakou S, Demertzis M. Anti-inflammatory properties of diclofenac transition metalloelement complexes. J Inorg Biochem. 1998;70:63–9.Google Scholar
- 10.Galwey AK, Brown ME. Thermal decompositions of ionic solids. 1st ed. Amsterdan: Elsevier; 1999.Google Scholar