Epithelial profiling of antibiotic controlled release respiratory formulations.

PURPOSE: Release profiles of two ciprofloxacin hydrochloride formulations for the treatment of respiratory infection were evaluated using different in vitro methodologies and characterised for aerosol performance and toxicity.
METHODS: Spray-dried ciprofloxacin and ciprofloxacin spray-dried with polyvinyl alcohol as a controlled release (CR) agent at a 50:50 w/w ratio were formulated and physico-chemically characterised. Aerosol performances were assessed in vitro using a liquid impinger. Drug release was performed using a modified Franz cell and a validated air interface Calu-3-modified twin stage impinger (TSI). Ciprofloxacin toxicity was also established in vitro.
RESULTS: Both formulations had a similar size distribution, while CR ciprofloxacin had superior aerosol performance and stability. The release profiles showed the CR formulation to have a higher transport rate compared to ciprofloxacin alone in the cell model. Contrary results were observed using the diffusion cell. Results suggest that the air interface cell model provides a more physiologically relevant model than the modified Franz cell. Toxicity analysis showed that the lung epithelial cells could tolerate a wide range of ciprofloxacin concentrations.
CONCLUSIONS: This study establishes that the in vitro modified TSI air interface Calu-3 model is capable of evaluating the fate of inhaled powder formulations.