THE TOXICITY AND LOCAL ANESTHETIC ACTIVITY OF THREE NEW BIPHENYL DERIVATIVES

¹ From the Department of Pharmacology, Temple University School of Medicine, Philadelphia

1. The hydrochlorides of -diethylaminoethyl-4-amino-4'-biphenyl carboxylate (compound V), di-(-diethylaminoethyl)-2-2'-diamino-5-5'-biphenylcarboxylate (compound VI) and di-(-diethylaminoethyl)-5-5'-diaminodiphenate (compound VII) were found to have marked local anesthetic properties.

2. The anesthetic activity of V after intradermal injection is slightly greater than that of the hydrochloride of p-amino-benzoyl-diethylamino ethanol (procaine) but it is also more toxic subcutaneously and produces tissue damage. While the anesthetic potency of VI is somewhat greater it is also more than twice as toxic subcutaneously as procaine. The marked anesthetic activity of VII as compared with procaine is offset by a five fold increase in subcutaneous toxicity.

3. The irritant properties of V and the poor depth of anesthesia produced by VI and VII make the present biphenyl compounds inferior to cocaine as topical anesthetics.

4. Comparison of V with closely related substances discloses that position of the substituent groups on the biphenyl nucleus alters local anesthetic activity. This also was observed in the case of compounds VI and VII.