Some observations on the -adrenoceptor agonist properties of the isomers of salbutamol.

1. The pharmacological activities of the optical isomers of salbutamol have been examined. (-)-Salbutamol was much more potent than (+)-salbutamol on beta-adrenoceptors.2. Both (-)- and (+)-salbutamol showed high selectivity for beta-adrenoceptors in bronchial muscle compared to cardiac muscle, in this way resembling racemic salbutamol.3. The use of isomeric activity ratio to detect differences between receptors was examined in the light of the results obtained with the isomers of salbutamol.