U-47700, also known as U4, U4100, and “pink,” is a synthetic opioid analgesic substance that was first developed in the 1970s by chemical and pharmaceutical company Upjohn.
U-47700, also known as U4, U4100, and “pink,” is a synthetic opioid analgesic substance that was first developed in the 1970s by chemical and pharmaceutical company Upjohn.