COMPARATIVE-STUDY OF 2 ETHYLCELLULOSE FORMS (RAW-MATERIAL AND MICROSPHERES) CARRIED OUT THROUGH THERMAL-ANALYSIS

The solvent evaporation method has been applied to ethylcellulose to prepare microspheres. The integrity of the polymer during the formulation has been followed by monitoring the physicochemical properties before and after the making of microspheres. Thermal analysis allowed the investigation of three factors: (i) polymer sorption, (ii) the glass transition and (iii) its aging - the oxidative degrActation process. All the observations are consistent with the view that ethylcellulose microspheres differ mainly from the raw material in their surface state. © 1990.