SINGLE-PARTICLE CHARACTERIZATION OF ALBUTEROL METERED-DOSE INHALER AEROSOL IN NEAR REAL-TIME

Metered dose inhalers produce a fine spray of aerosol particles that a re used as an inhalation drug delivery system for a variety of therape utic purposes. Common analytical methods employed for characterizing t he aerosol dosage are typically off-line analyses for both chemical in formation and particle size distributions, and focus on the bulk aeros ol rather than on single particles. Aerosol time-of-flight mass spectr ometry offers the capability to analyze the aerosol dose in near real- time, providing both size and chemical information for single particle s. Though aerosol time-of-flight mass spectrometry has been used prima rily to characterize environmental samples, this is the first demonstr ation of its bioanalytical capabilities. This paper discusses the char acterization of an albuterol metered dose inhaler using both high and low laser power for the desorption/ionization process in order to cont rol the amount of fragmentation observed in the mass spectral analysis . Using high laser power, significant fragmentation occurs with no maj or ion peaks above mass-to-charge 100 Da. In contrast, lower laser pow er allows for the observation of protonated and deprotonated parent io n in positive and negative ion analysis respectively. Also, high mass daughter ions are apparent in both positive and negative ion analysis. (C) 1998 American Association for Aerosol Research.