ABSTRACT
Various formulations of erythromycin base were designed to be controlled release forms. Tablets were prepared using Avicel as a diluent and both of stearic acid and magnesium stearate as hydrophobic materials to control the release. In addition, a control was prepared by direct compression of erythromycin base powder into tablets. On the other h and, microcapsules [MC] and solid dispersions [SD] of erythromycin base, which were prepared in a previous study, were either directly compressed into tablets or filled into hard gelatin capsules. Then, the formulated products were evaluated for hardness, disintegration time, penetration and dissolution rate testing. Also, the bioavailabilities of these products were investigated on humans. It was found that capsules containing MC or SD revealed higher release rate profiles compared to the corresponding tablets. On the other h and, products containing magnesium stearate were found to depict a reduction in drug release upon increasing magnesium stearate. However, the presence of stearic acid in the product resulted in a reverse effect