Formoterol suspension aerosol. Comparison with formoterol solution aerosol for 12 weeks in asthmatic patients

Formoterol solution aerosol has proved to be a fast and long-acting beta 2-sympathicomimetic drug in many clinical trials. The physical stability, however, was such that storage needed to be at 4 degrees C to 8 degrees C before first use; afterwards, the aerosol could be used for another three months at room temperature. To improve the stability, new ways have been investigated to formulate ann aerosol with improved shelf life and thus more convenient storage conditions, which was reached with a formoterol suspension aerosol. Equivalent single doses between the two formulations revealed no differences in onset or duration of action. In a double-blind, randomized parallel group multicenter study, organized in the Netherlands, 186 patients with stable asthma and reversible airway obstruction were treated either with one puff of 12 micrograms twice daily of formoterol metered dose inhaler (MDI) supension (SP) or a same dose of solution (SL) aerosol for 12 weeks to study the efficacy and tolerability of both presentations after a longer period of use. The following criteria of effectiveness were used: the FEV1 values on the mornings of the control days at 0, +4, +8, and + 12 weeks, the peak flow values (PEF) in the mornings and in the evenings before, and 1/2 to 1 h after treatment, the number of asthma attacks at night and during the day, the number of extra puffs at night and during day, and the subjective impression of patients and investigator.

No statistically significant differences between the two formoterol preparations were found. There was no indication of tachyphylaxis.

The results are consistent with the hypothesis that the biologic effects of formoterol when delivered from MDI containing the two different formulations of the drug are equivalent.