Stability, absorption, excretion, and distribution of nafiverine

The stability of a new antispasmodic, nafiverine, in an aqueous solution and in rabbit plasma was investigated. Metabolites of nafiverine in blood, bile, and urine were determined quantitatively. The effectiveness of an intramuscular administration of nafiverine was comparable to that of an intravenous administration. One metabolite of nafiverine, N-(2-hydroxyethyl)-N'-[alpha-(naphthyl)propionyloxy-2-ethyl]piperazine, is a new compound and its synthesis is described.