Clinical equivalence of a novel non-chlorofluorocarbon-containing salbutamol sulfate metered-dose inhaler and a conventional chlorofluorocarbon inhaler in patients with asthma.

BACKGROUND

New formulations of non-chlorofluorocarbon-containing propellants for pressurized metered-dose inhaler delivery systems must be developed in response to the forthcoming ban on chlorofluorocarbon (CFC) production.

OBJECTIVE

This study compared the bronchodilator effects of 100, 200, and 300 micrograms (base equivalent) of salbutamol in a novel CFC-free propellant system (Airomir in the 3M CFC-Free System; 3M Pharmaceuticals, St. Paul, Minn.; 108 micrograms of salbutamol sulfate or 90 micrograms of salbutamol base equivalent per inhalation) with that of 100 and 200 micrograms of salbutamol base in a conventional CFC propellant system (Ventolin, CFC-11/12; Allen and Hanburys, Division of Glaxo Inc., Research Triangle Park, N.C.; 90 micrograms of salbutamol base per inhalation) and placebo.

METHODS

Twenty-six patients with chronic, stable asthma, who had a forced expiratory volume in 1 second (FEV1) between 50.0% and 75.0% of predicted normal value, entered this randomized, double-blind, double-dummy, 6-period, crossover study. FEV1 was measured before and at multiple time points (ranging from 10 to 480 minutes) after administration of one, two, and three inhalations of salbutamol/CFC-free (100, 200, and 300 micrograms); one and two inhalations of salbutamol/CFC (100 and 200 micrograms); and placebo. Safety parameters included adverse events, heart rate, blood pressure, physical examinations, electrocardiograms, and clinical laboratory tests. Parametric analysis of variance models appropriate for a 6-period crossover design were used, along with multiple comparisons according to Tukey's method.

RESULTS

All active treatments produced significantly (p < 0.0001) greater bronchodilation than placebo. The bronchodilator effect, as measured by FEV1 (peak percent change, peak as a percent of predicted value, duration, and area under the curve) after two inhalations of salbutamol/CFC-free was clinically comprable to two inhalations of salbutamol/CFC, with no clinically meaningful differences in safety parameters between the two delivery systems or between different dose levels.

CONCLUSION

These results suggest that salbutamol/CFC-free may offer a suitable alternative for salbutamol/CFC when the need arises to change from CFC-containing salbutamol products.