Propylene glycol (PG), chemical formula C₃H₈O₂, CAS number 57-55-6, is a colorless, odorless, transparent liquid with a slightly sweet taste.
It is highly hygroscopic, readily soluble, and has low toxicity; it is miscible with water, alcohols, and many organic solvents.

Xanthan gum is a natural high-molecular-weight polysaccharide obtained by fermenting glucose or sucrose using Xanthomonas campestris.
It possesses excellent thickening, stability, suspending, and emulsifying properties. It dissolves rapidly in water to form a high-viscosity solution, making it a highly efficient and widely used natural biocolloid.