Polyethylene glycol 400 (PEG 400) is a low-molecular-weight grade of polyethylene glycol. It is a clear, colorless, viscous liquid .It is very hydrophilic and can augment the solubility and bioavailability of weakly water-soluble drugs. It finds applications in various industries, including pharmaceuticals, cosmetics. P.E.G 400 is commonly used as a solvent, emulsifier, and lubricant in formulations such as ointments, creams, lotions, and oral suspensions.