Preparation and in vitro evaluation of biodegradable microspheres with narrow size distribution for pulmonary delivery

Abstract

This study was performed to evaluate the feasibility of double emulsion technique combined with membrane emulsification to prepare microspheres for pulmonary delivery. An attempt was made to counter the shortcomings of microspheres; unsuitable size diameters and broad size distribution. Three formulation variables were optimized in order to achieve desired particle size and narrow size distribution. Compared with microspheres prepared by conventional double emulsion technique, the microsphere morphology, aerodynamic particle size, drug encapsulation efficiency and in vitro release were characterized in detail. The particles prepared by double emulsion technique combined with membrane emulsification showed the advantage on controlling the particle size to meet the requirement of respiration, as well as on encapsulation efficiency. Overall, this strategy could be promising for the application of pulmonary delivery.