Levalbuterol is the (R)-enantiomer of the drug substance racemic albuterol (salbutamol). Binding studies have demonstrated that (R)-albuterol binds to the beta2-adrenergic receptor with a high affinity, whereas (S)-albuterol binds with 100-fold less affinity than (R)-albuterol. Other evaluations have suggested that (R)-albuterol possesses the bronchodilatory, bronchoprotective, and ciliary-stimulatory properties of racemic albuterol, while (S)-albuterol does not contribute beneficially to the therapeutic effects of the racemate and was originally assumed to be inert. Xopenex (levalbuterol HCl) Inhalation Solution is indicated for the treatment or prevention of bronchospasm in adults, adolescents, and children 6 years of age and older with reversible obstructive airway disease.

Tartaric acid is found in many plants such as grapes, tamarinds, pineapples, mulberries and so on. Wine lees (called mud in the US), the sediment collected during the fermentation of grapes, contains potassium bitartrate (potassium hydrogen tartrate) as its major component. L-(+)-tartaric acid is an enantiomer of tartaric acid. Twenty five years before the tetrahedral structure for carbon was proposed in 1874 to explain the optical activity and other properties of organic compounds, Louis Pasteur discovered the existence of enantiomerism in tartaric acid. L-(+)-tartaric acid is widely used in food and beverage as acidity regulator with E number E334.