In Vivo Efficacy of Salbutamol (Sandoz) Versus Salbutamol Ventolin (GSK) in Children With Asthma

In this study, the investigators hypothesize that the reference product (SalbR/Ventolin) is more effective than SalbG (Salbutamol Sandoz) at improving the lung function in children with asthma, and that this difference increases alongside the severity of the airway resistance. (Null hypothesis: There is no difference). This could be explained by different properties and deposition of the aerosol. Purpose of this research: Rejecting the null hypothesis. This is based on the answers to the questions below. Research questions: 1. Is there a difference between the increase in FEV1 (and FVC) after 100 μg SalbG versus FEV1 after 100 μg SalbR in children aged 4-14 years with insufficient asthma control? (primary question) 2. Is there a difference in the subjective feeling of the children after inhalation with 100 μg SalbR and after 100 μg SalbG, measured with a VAS score? 3. Is the increase in FEV1 (and FVC) in children with asthma between 4-14 years of age with insufficient asthma control after inhalation of 400 μg SalbR different than after inhalation of 400 μg SalbG? 4. Is there a difference in the subjective feeling of the children after inhalation with 400 μg SalbR and after 400 μg SalbG, measured with a VAS score?