Pharmacokinetics of Beclomethasone Dipropionate Delivered by Breath-Actuated Inhaler and Metered-Dose Inhaler in Healthy Subjects

Background: Breath-actuated inhalers (BAIs) eliminate the need for hand-breath coordination required of pressurized metered-dose inhalers (MDIs). This pharmacokinetic study compared systemic exposure following beclomethasone dipropionate delivery through BAI versus MDI.

Methods: This open-label, three-period crossover, single-dose study randomized healthy subjects aged 18-45 years (N = 72) to 1 of 6 treatment sequences containing beclomethasone dipropionate BAI 160 mcg (40 mcg/inhalation, 4 inhalations), beclomethasone dipropionate BAI 320 mcg (80 mcg/inhalation, 4 inhalations), and beclomethasone dipropionate MDI 320 mcg (80 mcg/inhalation, 4 inhalations). Blood samples were collected predose through 24 hours postdose for determination of plasma concentrations of beclomethasone-17-monopropionate (17-BMP), the active metabolite of beclomethasone dipropionate. The primary pharmacokinetic parameters were area under the plasma drug concentration-time curve (AUC) from time 0 (predose) until the last measurable drug concentration (AUC_0-t) and maximum plasma drug concentration (C_max) for 17-BMP. Safety was assessed by adverse events, vital signs, clinical laboratory tests, and physical examinations.

Results: Plasma concentrations of 17-BMP peaked at a median of 10 minutes after the last inhalation of all study treatments and remained measurable for at least 18 hours in most subjects. Mean elimination half-life was ∼4 hours. The AUC_0-t and C_max for 17-BMP were 11% and 14% higher, respectively, when beclomethasone dipropionate 320 mcg was administered through BAI versus MDI, but the 90% confidence intervals of the geometric least squares mean BAI:MDI ratio for each parameter were fully contained within the bioequivalence boundaries of 0.80-1.25. Plasma concentrations of 17-BMP following beclomethasone dipropionate 160 mcg BAI were approximately half those with 320 mcg through BAI or MDI. All treatments were safe and generally well tolerated.

Conclusions: Systemic availability of 17-BMP following administration of beclomethasone dipropionate was bioequivalent between BAI and MDI at the 320-mcg dose, and approximately dose proportional at the 160- and 320-mcg doses using the BAI.