Pharmacokinetics and dose proportionality of beclomethasone from three strengths of a CFC-free beclomethasone dipropionate metered-dose inhaler.
As part of a development program to offer alternatives to chlorofluorocarbon (CFC) containing metered-dose inhalers, beclomethasone dipropionate has been formulated in a CFC-free system at three strengths: 50, 100, and 200 micrograms/actuation ex valve. To measure serum levels and dose proportionality of the beclomethasone derived from beclomethasone dipropionate, 13 mild to moderate asthmatic patients received a single dose of eight inhalations from each strength according to a double-blind crossover design. Seven patients were studied over 4 h and six patients over 12 h. For the total doses of 400, 800, and 1600 micrograms studied over 12 h, Cmax and AUC increased in a ratio of 1:1.8:3.1. A good correlation was seen between the fine-particle mass delivered and the in vivo performance of the three strengths. From a clinical point of view, the predictable increases in serum levels with an increase in dose will permit the clinician to effectively titrate a patient with this product.