Testing of adhesive properties of plasticized polyesters using rotational rheometer

Abstract

Title of thesis: Testing of adhesive properties of plasticized polyesters using rotational rheometer Author: Ogadah Chiazor Ugo Department: Pharmaceutical Technology Supervisor: PharmDr. Eva Šnejdrová, Ph.D. In this thesis, the rheological and adhesive properties of three polyesters intended for use as drug carriers in polymeric drug delivery systems were studied. The theoretical section summarizes the polymers used as drug carriers. Plasticizers, mechanism of action, types and uses and finally bioadhesion mechanism, application of the bioadhesive preparations, and methods of testing bioadhesion are reviewed. In the experimental section, ethyl salicylate, ethyl pyruvate and triethyl citrate were selected as the plasticizers to decrease the viscosity of the polyesters for easy processability, and setting of the optimal adhesive properties. Flow properties of the plasticized systems was measured with a rotational rheometer at temperature 37o C and a shear rate range from 0.10 to 100 s-1 . The analysis of the viscosity curves revealed that the resulting plasticized systems are mostly Newtonian. All tested plasticizers decrease the viscosity of the systems. The most effective is ethyl pyruvate. The adhesive properties were determined by the "pull away test" on the rotational rheometer, and evaluated as...