009127-PX
From Halopedia, the Halo wiki
009127-PX was the serial number for cyclodexione-4, a drug synthesized and used by the UNSC. It was a bipolar-integration drug.
It was one of three drugs injected into the Spartan-III Gamma Company illegally.[1] Cyclodexione-4, along with miso-olanzapine, were injected to counter the effects of the mutagen drug 009762-OO. However, this drug has to be administered regularly to prevent the mutagen from permanently affecting higher brain functions of the Spartans.[2] If it was not administered regularly, the Spartans would eventually break down mentally, becoming aggresive, irrational, and even psychotic.