The present work aimed to investigate whether lung deposition can be improved by using a device that optimizes the breathing pattern through electronic control. The relative lung deposition was estimated by inhalation of the marker substance, sodium cromoglycate (SCG), and measurement of urinary excretion of SCG. Thirteen cystic fibrosis (CF) patients (aged 8-20 years) received 20 mg of SCG as nebulizer solution by means of (a) conventional inhalation (Parimaster + Pari LC Star nebulizer, manual interrupter) and (b) electronically breath-controlled inhalation (AKITA + Pari LC Star nebulizer). Inhalations were trained and supervised by a physiotherapist. Patients were asked to provide answers to a questionnaire about the convenience of electronically breath-controlled inhalation. Urine was collected in five fractions until 12 h p.a., and the excreted SCG was determined by means of high-performance liquid chromatography (HPLC). Following breath-controlled inhalation, the amount of SCG excreted in urine was significantly greater than after conventional inhalation (2.22 +/- 0.61 mg vs. 1.63 +/- 0.59 mg, p < 0.001). The absorption half-life for SCG following breath-controlled inhalation was significantly shorter when compared with conventional inhalation (78 +/- 23 min vs. 107 +/- 29 min; p < 0.01), suggestive of a more peripheral deposition for the former. Ninety-two percent of the patients judged that the electronically breath-controlled inhalation was good or very good. In conclusion, inhalation with an electronically optimized breathing pattern yields a greater and more peripheral lung deposition of SCG compared with the manually triggered conventional nebulizer technique in CF patients with several years of aerosol inhalation experience.