Porous PLGA microparticles formed by "one-step" emulsification for pulmonary drug delivery: The surface morphology and the aerodynamic properties.

In the present study, by using a newly developed one-step emulsification technique, we tried to prepare porous PLGA particles having a proper diameter and surface morphology in order to achieve both a high efficient delivery of the particles to the lungs and a phagocytosis-avoidance ability. We found that our porous particles have the very low tapped density of 0.04g/cm3. Experimental and theoretical studies strongly suggest that the shape factor should not be determined only by the outline of the particles, although previous research assigned a value of 1 to the shape factor for particles regardless of the presence of pores and their distribution. We found the possibility that our porous particles both had specific internal structures induced by spontaneous emulsification and exhibited unusual aerodynamic performance.