Sample Collection
Subjects inhaled 2×100 µg salbutamol (nominal dose 200 µg). Salbutamol was delivered via their own MDI device. The inhaler delivered a nominal dose of 100 µg per actuation. Subjects emptied their bladders immediately before drug administration and then urine samples were collected 30 min after the inhaled doses. The collected urine samples were recorded and stored at −20 °C before analysis. A previously validated, sensitive high-performance liquid chromatography (HPLC) method was used to measure urine concentrations of salbutamol.16 Subjects did not drink alcohol or caffeine-containing beverages for 12 h before or 24 h after treatment. Demographic details like age, sex, disease characteristics were collected from each recruited patient. The study was approved by the Institutional Ethics Committee of the University (525/IHEC/3-19).