In Vitro Determination of Inhaled Mass and Particle Distribution for Budesonide Nebulizing Suspension

Abstract

ABSTRACT Nebulized delivery of aerosols to the lung is a complex process dependent on the device, the drug preparation, the patient's breathing pattern and other factors. It is difficult to predict drug delivery in advance and most delivery systems are studied empirically on the bench. To standardize the delivery of aerosolized budesonide suspension, we measured the quantity of drug delivered to the patient mouthpiece using a piston pump as a model of patient breathing and absolute filters. The mass of aerosol at the mouthpiece (the "inhaled mass") was determined by high-pressure liquid chromatography (HPLC). The aerodynamic properties of the nebulized budesonide particles were determined by cascade impaction and HPLC. Because the drug is used to treat children, the bench model was based on a "pediatric" breathing pattern, that is, a tidal volume of 200 mL, a breathing frequency of 25 per minute, and a duty cycle of 0.5. Twenty-seven nebulizer/compressor combinations were studied. Inhaled mass varied over...