Levosalbutamol tartrate(levalbuterol) is the R-enantiomer of the short-acting β2-adrenergic receptor agonist salbutamol. IC50 Value: Target: β2-adrenergic receptor Levosalbutamol and salbutamol produced significantly better bronchodilator responses than placebo. Both the drugs showed equivalent time-dependent bronchodilator responses as measured by area under curve for percent change in FEV(1) and FVC over 6h. The time to onset of action, mean maximum bronchodilator response and duration of bronchodilator response were similar between levosalbutamol and salbutamol [1].