Quantitative estimation of Eflornithine by Nitrite (Diazotization) titration

Eflornithine hydrochloride (DFMO) being a primary aliphatic amine reacts with the nitrous acid (in situ liberation by the reaction of ice cold sodium nitrite and hydrochloric acid) and gets converted to diazonium salt. At the end point an excess drop of titrant sodium nitrite from the burette liberates nitrous acid; this free acid is determined by the starch-mucilage paper, used as an external indicator. The free nitrous acid reacts with potassium iodide and reduces the iodide to free iodine, which produces intense blue color with the alpha-amylose portion of the starch indicating the end point. The Eflornithine hydrochloride (DFMO, Difluoromethylornithine) determined by Diazotization Titration (DAT M-01). Here the amino group of Eflornithine is diazotized with sodium nitrite solution in cold acid solution. The nitrous acid formed diazotizes the compound. The iodine formed reacts with starch mucilage to give the blue color. The end point can be determined by using starch iodide paper as external indicator. The percentage of purity in DFMO is found 99.74%.