USP propylene glycol
Propylene glycol — liquid of slightly viscous consistence.
It is colourless, has a characteristic weak smell.
Chemical formula of CH2(OH)-CH(OH)-CH3 propylene glycol. Also this substance is known under other names — a propane-1,2-diol, 1,2 pro-pan-diol, 1,2 dioxypropane. In a short form write so: PG, PG, PG 12, PGI.