Controlled-release behavior of diphenhydramine hydrochloride loaded neutral microgranules and coated using ethylcellulose water dispersion

The development of a loading method of a water-soluble drug using aqueous b inding solution to produce microgranules that were then coated with an aque ous ethylcellulose dispersion to sustain drug release is described. The res ults, in terms of drug used, showed that besides the fluidized bed paramete rs, the amount;of drug dissolved in the binder solution plays an important role in obtaining a satisfying result during the spraying process. Thus, it seems necessary to determine the critical concentration above which the ma terial started to adhere to the interior of the fluidization column, and th e possibility of drug layering onto carrier material is aggravated. ANOVA o f the time parameter for release of 63.2% of total drug (td) value showed s ignificant influence of ethylcellulose (Aquacoat ECD-SO) and dibutyl sebaca te concentration on diphenhydramine hydrochloride (DPH) release. The dissol ution rate decreased with an increase in polymer concentration. The diffusi onal-exponent n of the Peppas equation indicated that the DPH release kinet ic was non-Fickian but approached Fickian diffusion, particularly at higher coating levels.