Ziroxin-12 was a poison with a precise delivery mechanism that existed by the time of the Galactic Civil War. Between 3 ABY and 4 ABY, the poison was sold by Zlarb on the planet Coruscant. The assassin Ochi of Bestoon visited Zlarb's to acquire poisons for a job he was to pull off for Lady Qi'ra of Crimson Dawn. The job, which was the assassination of Emperor Palpatine's Royal Guard, required Ochi to use a poison with precise timing which, after the assassin mentioned the fact to Zlarb, prompted Zlarb to suggest Ziroxin-12.
Ochi later traveled to the The Works District where he had an use the Ziroxin-12 to poison the breakfast of the Royal Guards, though he noticed that one of the guards were not present at the time. The assassin later found the guard, Major Erstin Deez, and due to the difference in timing with the poison he had given to the other guards, was forced to use Yurfloo.