Microcapsules of phenylpropanolamine hydrochloride with core: wall ratios of 1:1, 2:1 and 1:2 were prepared by the coacervation-phase separation method, using ethylcellulose as the coating material. Two batches of PPA.HCl powder with different particle sizes ( > 58 mum and < 28 mum) were used as the core material. The different sizes of microcapsules were separated using a range of standard sieves (840-247 mum). The effects of drug particle size, the media pH and the core: wall ratio on the dissolution kinetics were studied, and evaluated kinetically.