Trojan microparticles of budesonide palmitate nanoparticles: formulation optimization for lung delivery.

A prodrug of budesonide, budesonide palmitate, was synthesized and formulated into nanoparticles by emulsion-evaporation, using a PEGylated lipid, DSPE-mPEG, as the sole excipient. Spherical nanoparticles of about 200 nm were obtained, with prodrug content between 57-73% by weight. To deliver nanoparticles to the lungs as dry powders, Trojan microparticles containing 5%-20% (w/w) of these prodrug-based nanoparticles were formulated for the first time by spray drying. Results show that the fine particle fraction decreases as the nanoparticle percentage increases. The formulation with 5% nanoparticles is optimal for targeting the alveolar region, with a mean mass aerodynamic diameter of 3.3 μm, a fine particle fraction of 67%, and an alveolar particle fraction of 41%. These Trojan microparticles appear to be promising carriers for the treatment of respiratory diseases via lung delivery.