EFFECT OF BIODEGRADABLE CO-POLYMERS AND DIVALENT CATIONS ON THE SUSTAINED RELEASE ABILITY OF PROPRANOLOL HYDROCHLORIDE LOADED BIOMATERIAL MICROSPHERES Journal title: International Journal of Pharmacy and Pharmaceutical Sciences Authors: Shahira F El-menshawe, Rasha M. Kharshoum, Doaa S Hamad, Abdelkhalek Halawa Subject(s):