Delay Between Shaking and Actuation of a Hydrofluoroalkane Fluticasone Pressurized Metered-Dose Inhaler

Inhaled corticosteroids are used to treat pediatric asthma. The shaking of a pressurized metered-dose inhaler (pMDI) is required to ensure consistency of emitted dose. Delays between shaking and actuating the pMDI are frequent during administration of aerosols to children where a valved holding chamber is used.

In a recent clinical trial, we used a monitoring device to record shaking and actuation of the pMDI and the inhalation profiles of children with asthma while they were inhaling fluticasone hydrofluoroalkane from a valved holding chamber onto an external filter. During the procedure, in vitro and transport samples were generated without a delay between shaking and actuating the pMDI. Emitted dose, expressed as percentage of ex-actuator nominal dose, obtained from the second actuation following a recorded shake-actuation interval for subjects and from in vitro/transport samples (no delay) were compared.

The mean emitted dose was 158.6% (95% CI 150.1-167.2%) (subjects) and 106.8% (95% CI 104.7-108.9%) (in vitro + transport) of the ex-actuator nominal dose (P < .001). The mean delay between shaking and actuating the pMDI was 12.9 s (95% CI 11.9-13.9 s) for the subject samples. A strong correlation was observed between shake and actuation delay and the emitted dose of the second actuation following the delay (Spearman correlation coefficient = 0.61). A 10-, 20-, and 30-s delay resulted in an emitted dose of the second actuation following the delay of 147, 187, and 227% of the ex-actuator nominal dose, respectively.

Delays between shaking and actuating a corticosteroid suspension pMDI resulted in an increase in the emitted dose of the second actuation following the delay. This can be a common occurrence when doses are administered by a caregiver to a patient via a holding chamber. This should be addressed by practitioners educating patients and parents on proper inhaler use. (ClinicalTrials.gov registration NCT01714063.).