Abstract
The long-term efficacy of inhaled aerosol medications depends largely on the uniformity of pulmonary drug deposition. Aerosol antibiotics are currently used for treatment of lunginfections associated with cystic fibrosis (CF). Due to the decreased ventilation caused by airway obstructions associated with CF, drug is not deposited uniformly and certain regions of the lung go untreated. Previous in vitro studies have shown that when the deposited surfactant solution has a surface tension lower than that of the mucin solution, surface tension gradient driven or “Marangoni” flows are created [1]. It has been observed that surfactant enhances aerosol spreading on hydrated mucus surface as compared to saline [2]. We study the spreading of aerosolized aqueous surfactant solutions on entangled, aqueous subphase solutions, used to mimic the airways surface liquid (ASL) of the lung. The goal of this in vitro study is to determine the optimal surfactant and concentration that can be used as a carrier for pulmonary aerosol drug delivery in a future in vivo study. Experiments were carried out to compare the spreading of three surfactants as a function of their concentration on 1 % w/v Polyacrylamide solution. Amongst the three surfactants that were compared, the most effective surfactant as potential aerosol drug carrier, Tyloxapol, was then deposited on a subphase of Porcine Gastric Mucin to study its spreading efficacy as a function of its concentration. The effect of type of subphase on spreading behavior was also studied for Tyloxapol by carrying out experiments keeping all parameters constant except the subphase type.
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