Conventional and composed promethazine-loaded microspheres
were prepared by spray drying of chitosan solution systems and double water-inoil-
in-water (W/O/W) emulsion systems, respectively. Double emulsions were
prepared in two different feed concentrations, with chitosan dissolved in both
water phases, and ethylcellulose dissolved in oil phase. Swelling and bioadhesive
properties of the microspheres depended on the chitosan content, type
and the feed concentration of spray-dried system. Results obtained suggested
that better ethylcellulose microcapsules with promethazine in the chitosan
matrix were formed when less concentrated emulsion systems were spray-dried.
Thus, in case of such a system, with ethylcellulose/chitosan weight ratio of
1:2, prolonged promethazine release was obtained
