Evaluation of a new Aerodynamic Particle Sizer Spectrometer for size distribution measurements of solution metered dose inhalers.

The ability of the Model 3320 and newer Model 3321 Aerodynamic Particle Sizer Spectrometer (APS) to make accurate mass-weighted size distribution measurements of solution metered dose inhalers (MDIs) was evaluated. Measurements of experimental HFA-134a beclomethasone dipropionate MDIs were made with both the APS 3320 and APS 3321 and compared to the Andersen Cascade Impactor (ACI). The mass-weighted size distribution measurements from the ACI and APS 3321 agreed well but were very different than the APS 3320 measurements.

Advances in metered dose inhaler technology with the development of a chlorofluorocarbon-free drug delivery system.

The impending phaseout of chlorofluorocarbon (CFC)-containing metered dose inhalers (MDIs) has challenged the pharmaceutical industry to rethink and redesign many components of the technology involved in delivering asthma medication to the lungs. Along with the emergence of the first formulation using the nonozone-depleting propellant, hydrofluoroalkane (HFA) 134a to replace CFC propellants, advances in drug delivery technology have improved the performance characteristics of the MDI itself. Although MDIs have remained the mainstay of asthma therapy for 40 years, MDI technology still presents challenges.

A new method to evaluate plume characteristics of hydrofluoroalkane and chlorofluorocarbon metered dose inhalers.

Two concerns raised when comparing metered dose inhalers (MDIs) to other inhalation devices are their relatively high throat deposition and the 'cold-Freon' effect seen in a small number of patients. The cold-Freon effect is presumed to be a result of the cold, forceful MDI plume impacting on the back of a patient's throat. This in vitro study uses a new plume characterization method to determine the spray force and plume temperature of various MDIs.