A hydrogel microparticle with sustained release properties for pulmonary drug delivery

Inhalable hydrogel microparticles are desirable pulmonary drug delivery systems with sustained release properties. In the present study, a hydrogel microparticle composed of Zn2+, carboxymethyl chitosan and hyaluronan aldehyde for pulmonary drug delivery has been constructed by spray drying approach. The optimized microparticles had a mean geometric particle size between 2 and 5 μm. The aerodynamics characteristic determination found the fine particle fraction approximately 40% and average mass median aerodynamic diameter of 5.5 μm. The microparticles loaded with theophylline showed a sustained drug release profile over 24 h in vitro. The formulation avoided the alveolar macrophage clearance, and had substantially longer residence time in vivo. In addition, it showed significant inflammation alleviation in the lung tissues compared with the theophyllinum only group on OVA induced asthmatic mice. In conclusion, the microparticle can be considered as a potential alternative of pulmonary drug delivery system for lung disease therapy.