A Study to Investigate How Budesonide and Formoterol Move Through the Body (Pharmacokinetics) When Delivered With Different Devices in Participants Aged 4 to Less Than 12 Years Old With Asthma

This study looks at how two common asthma medications — budesonide (a steroid) and formoterol (a bronchodilator) — are absorbed and processed by the body when delivered by different inhaler devices in children aged 4 to under 12 with asthma. **You may be eligible if...** - Your child is between 4 and under 12 years old - Your child has been diagnosed with asthma by a clinician for at least 3 months - Your child's weight is at least 15 kg and their BMI is at or below the 95th percentile for their age - Your child has been on a stable asthma treatment for at least 4 weeks **You may NOT be eligible if...** - Your child has a severe or unstable asthma condition - Your child has significant other health problems (heart, liver, or immune conditions) - Your child has recently had a chest infection or asthma attack - Your child is unable to use an inhaler correctly Talk to your doctor to see if this trial is right for you.