Structure-activity relationships local anaesthetics

Broadly speaking, it has been observed critically amongst all the known local anaesthetics , which are invariably employed in clinical practice, that there exists no clear-cut and obvious structure activity relationship in them. Besides, a plethora of these clinically prevalent and useful local anaesthetics are importantly tertiary amines , such as Butacaine, Bupivacaine, Dibucaine, Lidocaine, Mepivacaine, Prilocaine, Pramoxine, Proxymetacaine, Tetracaine etc. 

Bean et rz/.(1983) assumed it to be true as a logical basis for reasoning the structure activity relationships amongst the known local anaesthetics as per the following specific structural characteristic features put forward under Lofgren s classification as illustrated below in Table 4.1. 

It will be now worthwhile to elaborate and discuss the structure-activity relationship of certain specific examples of local anaesthetics vis-a-vis the aforesaid three separate zones imbeded into the drug molecule. 

A large number of new tropanyl esters and other related compounds have been prepared, with the purpose of contributing further structure-pharmacological activity relationships. Inter alia, para-substituted tropanyl benzoates (for studies of the substrate specificity of atropine esterase), benzazocines (narcotic antagonists) from 6-hydroxytropinone, 5-aryl-furan-2-carboxylic esters of pseudotropine (local anaesthetics), 2,4,5-trimethylpyrrole-3-carboxylic acid... 

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