A STUDY OF TWO SERIES OF PROCAINE DERIVATIVES WITH REFERENCE TO THE RELATIONSHIP BETWEEN THEIR PHARMACOLOGICAL ACTION AND CHEMICAL CONSTITUTION

¹ From the Pharmacological Laboratory of the University of Wisconsin

Two series of local anesthetics, (a) amino ethanol esters of para amino benzoic acid, and (b) the corresponding trimethylene derivatives, were investigated with respect to the relationship of constitution to action.

In these series there is an increase in anesthetic activity on the rabbit's cornea and an increase in toxicity to mice with the substitution of higher alkyl groups. The increase in activity is proportional to the increase in toxicity.

The iso-propyl compounds are more efficient and more toxic than the normal propyl compounds. Again the increase in anesthetic activity is proportional to the increase in toxicity.

Each trimethylene compound produces anesthesia of longer duration and is more toxic than the corresponding dimethylene derivative. Here the increase in toxicity is greater than the increase in anesthetic power and as a result the therapeutic indices of the dimethylene compounds are greater than those of the trimethylene compounds.