Abstract: A series of experiments were performed to investigate the effect of particle size on the dissolution rate of ibuprofen (IBF) powders. Dissolution studies were conducted under nonsink conditions and dissolution rates of six sieved particle size fractions (<65, 65~74, 74~91, 91~125, 125~150, and 150~200 μm) were compared. Dissolution rates of the fractions with particle size >74 μm increased with reduction of particle size. On the other hand, fractions enclosing particles with a size <74 μm demonstrated different profiles and slower initial rates of dissolution. This could be due to the development of electrostatic charge on the particles during micronization. Dissolution measurements of binary systems mixed at various ratios of the sieved samples were also carried out. Simulation of the dissolution process of the mixed binary systems was performed using the dissolution values of the sieved fractions. The simulated dissolution curves coincided well with those measured over almost the whole dissolution process. The evaluation of the dissolution behavior of the mixed binary systems and their simulation appears to be useful in the estimation and prediction of dissolution rates of multiparticulate powder systems.

Key words: Ibuprofen powders, Particle size, Dissolution rate, Mixed binary systems, Simulation of dissolution process