Single-isomer beta-agonists

For over a century, beta -agonists have been used for the treatment of asth ma and obstructive airway diseases. The drugs of this class each have a chi ral carbon, thus, when synthesized, contain a 50:50 mixture of R- and S-iso mers. The R-isomerisomer, being an adrenaline analog, possesses bronchodila tor and bronchoprotective properties; the S-isomer has no therapeutic benef its. Studies differentiating the biological activities of R- and S-albutero l have suggested that the S-isomer has properties which are inappropriate f or an asthma medication. Recently, R-albuterol (levalbuterol) has become av ailable and seminal studies have demonstrated that the removal of S-albuter ol from racemic albuterol creates a more efficacious therapeutic for mild p ersistent to acute asthma.