A Clinical Study of a Methacholine Dry Powder for the Bronchial Challenge Test

Methacholine (MCH) is used to perform the bronchial challenge test for the diagnosis of asthma where it is necessary to determine if an individual has hyper-responsive airways. The aim of this work was to develop a new method for MCH challenge test using pre-metered respirable MCH powders at different doses for performing brochial challenge studies. The availability of a series of pre-metered doses gives greater control on aerosolized dose and fine particle dose (respirable dose), improving the accuracy and repeatability of the test. A dosimetric challenge test, comparing MCH dry powder and MCH solution for asthma detection, was performed in eighteen subjects.