Estimation of Transition Temperature of Pharmaceutical Polymorphs by Measuring Heat of Solution and Solubility
| Autor: | Koji Urakami, Kazuichi Umemoto, Yasushi Shono, Atsuya Higashi, Masayuki Godo |
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| Rok vydání: | 2002 |
| Předmět: | |
| Zdroj: | Bulletin of the Chemical Society of Japan. 75:1241-1245 |
| ISSN: | 1348-0634 0009-2673 |
| DOI: | 10.1246/bcsj.75.1241 |
| Popis: | The transition temperature for enantiotropic polymorphs of pharmaceutical drugs was estimated by measuring the heat of solution and solubility at 25 °C. Instead of the conventional estimation method using van’t Hoff plots, a thermodynamic formula was derived with the heat of solution and solubility as variables for calculating the temperature at which the Gibbs free energy difference between two polymorphs in enantiotropic system become zero. The transition temperatures of polymorphic pairs for five model compounds (seratrodast, mefenamic acid, sulfathiazole, acetazolamide, and carbamazepine) calculated by the formula were in good agreement with previous studies. Since this formula requires solubility data at only one arbitrary temperature other than the heat of solution data for both polymorphs in a polymorphic pair, the proposed method is much faster than the conventional method, requiring solubility data at five or more different temperatures for preparing van’t Hoff plots. |
| Databáze: | OpenAIRE |
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