Characterization of enalapril maleate: An approach using thermoanalytical, thermokinetic and spectroscopic techniques
| Autor: | Augusto Teixeira José, Santos de Souza Adrian, da Silva Laís Mendoza Kardek de Melo, Denck Colman Tiago André |
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| Jazyk: | angličtina |
| Rok vydání: | 2024 |
| Předmět: | |
| Zdroj: | Journal of the Serbian Chemical Society, Vol 89, Iss 10, Pp 1353-1362 (2024) |
| Druh dokumentu: | article |
| ISSN: | 0352-5139 1820-7421 |
| DOI: | 10.2298/JSC231207070A |
| Popis: | Enalapril maleate is a widely used drug for the treatment of cardiovascular diseases. Its mechanism of action is to inhibit the angiotensin-converting enzyme selectively. Therefore, it is metabolized to enalaprilat by liver cells. The thermal behaviour of enalapril maleate was investigated by simultaneous thermogravimetry and differential scanning calorimetry (TG-DSC), as well as with evolved gas analysis by simultaneous thermogravimetry and differential scanning calorimetry coupled infrared spectroscopy (TG-DSC–FTIR). The results provided information on thermal stability, purity, thermal decomposition steps and the main products formed in the heating. The enalapril maleate was found to be stable up to 148 °C. Above this temperature causes thermal degradation of the substance, which occurs in two stages in an inert atmosphere (N2) and three stages in an oxidizing atmosphere (air). Through the TG-DSC–FTIR the released gases were identified as maleic anhydride as a thermal decomposition intermediate. DSC analysis showed that the material obtained 99.5 % purity, which indicates high purity. Employing both the Kissinger and Friedman equations, alongside model fitting methods, the study reveals key insights. The Kissinger method unveils an apparent activation energy of 47.07±15.45 kJ mol-1 for the complete thermal breakdown, a finding corroborated by the Friedman method. Model fitting methods, the article applies them, yielding an apparent activation energy of 55.7±3.4 kJ mol-1 with a three-dimensional diffusion thermal degradation model. |
| Databáze: | Directory of Open Access Journals |
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