Etofenamate fatty acid asters. An example of a new route of drug metabolism.

Etofenamate [2-(2-hydroxyethoxy)ethyl-N-(alpha, alpha, alpha-trifluoro-m-tolyl)-anthranilate] was administered to dogs by the oral route. Minor amounts of etofenamate (Eto) and its glucuronide were found in urine and feces. The main portion of metabolites was eliminated as flufenamic acid (Flu) and hydroxy derivatives of Eto and Flu. Furthermore, a highly lipophilic fraction was isolated (extraction and TLC) and further separated into several compounds (HPLC, GLC). These metabolites were identified as Eto oleate, palmitate, linoleate, stearate, palmitoleate, myristate, and laurate by NMR and MS. The structures were confirmed by comparison with authentic material. The conjugation of etofenamate with fatty acids is an example of a new route of drug metabolism.