Journal of Clinical & Experimental Pharmacology

Stability studies of lysine acetylsalicylate (aspirin derivative): Mechanisms of hydrolysis

3^rd World Congress on Pharmacology

August 08-10, 2016 Birmingham, UK

Oussama Kamal

University Hassan II, Morocco

Posters & Accepted Abstracts: Clin Exp Pharmacol

Abstract:

To control the stability of the Lysine Acetylsalicylate Compound (LAS) in aqueous solution, some studies of the hydronium ioncatalyzed, hydroxide ion-catalyzed, and spontaneous reactions of this active ingredient in water solutions have been carried out. The pH-rate profile (log kobs=f (pH)), shows that the hydrolysis reaction of the LAS, is conducted by a catalysis of acid-base mechanism, with multiple reaction pathways. The rate constants kH, kOH and k0 of the reaction pathway catalyzed by H3O+ and HO- ions and the spontaneous reaction, for the hydrolysis reaction of the reagent LAS, were determined. The results show that the studied compound (LAS) is unstable in basic medium and the hydrolysis reaction catalyzed by HO- ions is predominant. For a known acidity (pH 10), studies were conducted for different temperatures of the medium, which clearly indicate, that the experimental rate constant kobs, depends on the temperature according to the Arrhenius law. The activation parameters like Ea, �?�H�?� and �?�S�?�, for the transition state were determined. The high negative value obtained for the activation parameter �?�S�?�, first indicates that in the transition state there is a gain and then in the late state it resembles the product that probably is for the mechanism of the lysine acetylsalicylate hydrolysis reaction which is catalyzed by HO- ions, where the rate-determining step is a bimolecular reaction. Finally from all these results, the mechanism for the reaction pathway catalyzed by HO- ions has been elucidated.

Biography :

Email: kamaloussama@hotmail.fr