QSAR in a series of muscarinic agents

The results of a pharmacological investigation on a series of 3-substituted benzyltrimethylammonium salts possessing muscarinic activity are reported. Correlative analysis shows that the pharmacodynamic activity is a function of the hydrophobic-lipophilic and steric parameters associated with the substituents. In particular, it is revealed that a lipophilic pocket of limited size is present in the muscarinic receptor at an optimal distance from the electron--rich site with which the cationic termination interacts.