Study of Immobilization by Esteric Bond of 2-(m-Nitrophenyl)-4-(ОІ- Carboxymethyl)-О”2-Oxazolinone-5 on Gellan

The paper studies the coupling reaction, through ester-type covalent bonds, of an oxazolone derived from the N-(m-nitrobenzoyl)-L-asparagic acid, on gellan (a polysaccharide of microbian synthesis), in conditions of activation with dicyclohexyl carbodiimide. Based on a centered, rotatory, composed, second order experimental program, the regression equation describing the dependence of the amount of active principle, chemically bounded to the support, on the reaction’s  parameters (support/active principle ratio, active principle/activator ratio, duration) is obtained. One may observe that the efficiency of the coupling reaction is maximum when employing the parameters’ highest values, over the variation domain established. The coupling product has been characterized through elemental analysis and IR spectroscopy. For the establishment  of the capacity of the active principle’s controlled release by the polymer-active principle system thus obtained, drug’s release kinetics from the polysaccharidic support is studied in conditions of basic hydrolysis. The oxazolone release from the coupling products, by basic hydrolysis proceeds conformely to a zero order kinetics, proving their retard activity