Abstract: Process for the preparation of pure allylamine pharmaceutical terbinafine of formula I in free base form or acid addition salt form, by distilling crude terbinafine base, preferably by short path distillation, e.g. at a temperature above 100° C. and reduced pressure, e.g. 0.2 mbar, and recovering the purified product in free base or acid addition salt form. The process is indicated for use in removal of metal or non-metal contaminants, optionally together with salt formation under simultaneous precipitation of pure trans isomer. Detection of non-metal contaminants such as substance A of formula preferably is effected by RP HPLC analysis with UV detection.

Abstract: Process for the preparation of pure allylamine pharmaceutical terbinafine of formula I in free base form or acid addition salt form, by distilling crude terbinafine base, preferably by short path distillation, e.g. at a temperature above 100° C. and reduced pressure, e.g. 0.2 mbar, and recovering the purified product in free base or acid addition salt form. The process is indicated for use in removal of metal or non-metal contaminants, optionally together with salt formation under simultaneous precipitation of pure trans isomer. Detection of non-metal contaminants such as substance A of formula preferably is effected by RP HPLC analysis with UV detection.