SYNTHESIS AND ANALGESIC ACTIVITIES OF UREA DERIVATIVES OF ALPHA-AMINO-N-PYRIDYL BENZENE PROPANAMIDE

New urea L-phenyl alanine derivatives of 4-aminopyridine have been syn thesized and evaluated for analgesic activity with the PBQ writhing te st in mice and the Randall-Selitto test in rats. Potent oral activity (ID50 < 10 mg/kg) and good tolerance were found in alkyl, arylalkyl an d carboxyalkyl urea derivatives. The analgesic activity was found to b e totally dependent on the pyridine moiety and was at least partly inh ibited by pretreatment with (alpha) methyltyrosine, as was the case fo r 4-aminopyridine. These compounds are therefore pharmacologically int eresting as new analgesic derivatives of 4-aminopyridine. They have a higher oral activity and a better activity/tolerance profile.