| Autor: |
A. Li Wan Po, Q.N. Masuda, W.J. Irwin |
| Rok vydání: |
1984 |
| Předmět: |
|
| Zdroj: |
International Journal of Pharmaceutics. 21:35-50 |
| ISSN: |
0378-5173 |
| DOI: |
10.1016/0378-5173(84)90201-1 |
| Popis: |
Salicylate esters undergo reversible transesterification in alcoholic solutions in which the ester radical differs from that of the alcohol. The reactions are base-catalyzed and the predominant pathway involves a concerted solvent attack upon the salicylate anion. Competitive hydrolysis of both ester components also follows this mechanism at moderate pH values but rates increase under strongly alkaline conditions as direct hydroxide attack becomes significant. In contrast, transesterification is independent of base concentration once full ionization is accomplished. Equations are presented to model the time-profile of reactant and product concentration. The process may affect the integrity of pharmaceutical formulations and a gel formulation is shown to degrade rapidly. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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