Bronchodilating activity of broxaterol transdermal patch and its protective effect on bronchial constriction induced by inhaled distilled water mist.

The bronchodilating activity and the ability of broxaterol transdermal patch to inhibit bronchial constriction in response to distilled water mist (UNH2O) inhalation were assessed. The study was performed in 10 asthmatic patients in clinical remission according to a placebo-controlled, double-blind, randomized crossover design. Test medications were broxaterol patch (size = 1.75 cm2; programmed delivery = 105 mcg/h) and a matched placebo patch. A spirometric examination was performed before patch application (at 8:30-9:00 a.m.) and 24 hours later. Immediately afterwards, the UNH2O inhalation test was made, consisting of 3 bronchial exposures lasting 30, 60 and 120 s respectively with 3-minute intervals between challenges. Immediately after each exposure, a spirometric examination and specific airway resistance measurements were made. The results obtained show that broxaterol patch exerts a statistically significant bronchodilating effect and has a better protective effect than placebo patch on UNH2O-induced bronchial constriction. The local tolerability of patches was very good. Slight tremors were observed in some subjects.