There are increasing interests to deliver drug nanoparticles to the lungs to achieve superior in vivo efficacy and minimized lung clearance. The rationales to design nanoparticle formulation for inhaled antibiotics include prolonged airway retention by reducing mucociliary clearance, increased solubility and dissolution rate of poorly water-soluble drugs, and superior penetration into biofilm and bacteria cells. Cefuroxime axetil nanoparticles were generated by sonoprecipitation (Dhumal et al. 2008) and high-gravity antisolvent precipitation (Heng et al. 2008) with enhanced dissolution. Polymeric antibiotic nanoparticles made of poly (lactic-co-glycolic) acid and chitosan (Abdelghany et al. 2012, Grumezescu et al. 2013) and solid lipid nanoparticles (Ghaffari et al. 2010, Varshosaz et al. 2012) have shown improved antimicrobial efficiency.
Due to the extremely small mass, there is a concern that nanosized particles may be exhaled. This problem can be solved by either holding the breath postinhalation or forming matrix microparticles. Yamasaki et al. produced a mannitol matrix microparticle containing cyclosporine nanoparticles with enhanced dissolution (Yamasaki et al. 2011). The strategy of forming inhalable matrix microparticles can also be applied to antibiotic nanoparticles.