Pulmonary Anti-inflammatory Effects of Chitosan Microparticles Containing Betamethasone

Chitosan microparticles (CMs) are of potential interest for controlled delivery of therapeutic agents to cells and tissues, especially to mucosal-epithelial surfaces in the body. CM incorporation efficiency and release kinetics for betamethasone (B), an epimeric synthetic glucocorticoid, were investigated. Evidence for mild but significant inflammatory reactions in rat lung exposed to high CM concentrations was observed. Inflammation in the rat lung was significantly decreased by inhalation of B-loaded CMs (BCMs). Decreases in bronchoalveolar lavage fluid protein, content of polymorphonuclear neutrophils, lactate dehydrogenase (LDH) activity, lung tissue myeloperoxidase (MPO) activity, and leukocyte infiltration were observed. For all biochemical parameters tested, CMs loaded with 1.0-1.2mg/kg B decrease the inflammation by 1.63±0.14 fold, to near air-inhalation control levels. Thus, the drug was efficiently delivered and active in the pulmonary tissues by this technique.