Preparation and in vitro evaluation of etoposide-loaded PLGA microspheres for pulmonary drug delivery

Pulmonary drug delivery has become a promising route in the treatment of lung diseases because of better local retention and lower systemic penetration. In this study, etoposide-loaded poly(lactic-co-glycolic acid) ( PLGA) microspheres were designed with potential pulmonary delivery properties. The microspheres were prepared via improved emulsion-solvent evaporation method. Physicochemical characteristics, micromeritics properties and in vitro drug release behavior of the microspheres were then evaluated. Results showed that etoposide-loaded PLGA microspheres were spherical in shape with smooth surface with size (11.8 +/- 1.25) mu m. Particles remained stable without any changing in size and morphology after dried by the freeze-drying method. Etoposide was loaded into PLGA microspheres in an amorphous state with high drug loading ((7.7 +/- 0.3)%) and encapsulation efficiency ((84.2 +/- 2.9)%). Results of micromeritics properties also demonstrated that etoposide- loaded PLGA microspheres were very suitable for pulmonary delivery. In addition, in vitro drug release study indicated a sustained release profile fitted with the Ritger-Peppas equation for up to 20 days. In conclusion, the etoposide- loaded PLGA microspheres were promising for pulmonary delivery, and etoposide could be sustained released from the PLGA microspheres.