Fenfluramine compositions and methods of preparing the same

A method of treating epilepsy, comprising administering to a patient a therapeutically effective amount of a formulation comprising a fenfluramine active pharmaceutical ingredient produced by a process comprising the steps of:

• (a) hydrolyzing a 2-(3-(trifluoromethyl)phenyl)acetonitrile composition to produce a 2-(3-(trifluoromethyl)phenyl)acetic acid composition;
• (b) purifying the 2-(3-(trifluoromethyl)phenyl)acetic acid composition via crystallization to produce a purified 2-(3-(trifluoromethyl)phenyl)acetic acid having less than 0.2% by weight in total of trifluoromethyl-phenyl regioisomers;
• (c) reacting the purified 2-(3-(trifluoromethyl)phenyl)acetic acid composition with acetic anhydride and a catalyst to produce a 1-(3-(trifluoromethyl)phenyl)propan-2-one composition;
• and
• (d) reductively aminating the 1-(3-(trifluoromethyl)phenyl)propan-2-one composition with ethylamine using a borohydride reducing agent to produce a fenfluramine active pharmaceutical ingredient comprising at least one trifluoromethyl-phenyl regioisomer of fenfluramine, wherein the at least one trifluoromethyl-phenyl regioisomer of fenfluramine is present in some amount;
• wherein the fenfluramine active pharmaceutical ingredient has the following profile:
• at least 80% by weight of fenfluramine or a salt thereof
• at least 0.01% by weight of 2-fenfluramine or a salt thereof;
• at least 0.01% by weight of 4-fenfluramine or a salt thereof;
• and
• less than 10% by weight of fenfluramine reduced alcohol side product.