Salbutamol

Levalbuterol was launched in the US for the treatment or prevention of bronchospasm in patients with reversible obstructive airway disease. It is the single R-enantiomer version of racemic albuterol (salbutamol) marketed for more than 30 years as a mainstay in the treatment of asthma. The R-isomer can be obtained with an excellent optical purity by enantiomeric purification based on the separation of diastereomeric tartrates. This isomer retains solely the desired bronchodilating effect of the racemic mixture due to a potent agonistic effect on β2-adrenoceptors, with a lower incidence of β- mediated side effects such as pulse rate increase, tremor and decrease in blood glucose and potassium levels. A pivotal clinical trial with two doses of levalbuterol and racemic albuterol, given by nebulization, demonstrated a greater improvement in lung function for the pure enantiomer levalbuterol.

(R)-Salbutamol is used in composition and methods to reduce beta-agonist-mediated tachyphylaxis.