PEG300

Polyethylene glycol 300 (PEG300) is a low-molecular-weight polyethylene glycol with an average molecular weight of ~300. It is a colorless, viscous liquid, strongly hydrophilic, and miscible with water and a variety of organic solvents. In biomedicine, it is mainly used as a pharmaceutical excipient: commonly used as a solvent/co-solvent, vehicle, viscosity enhancer, and humectant in oral, injectable, and topical formulations, and can significantly improve the solubility and stability of hydrophobic small molecules and some peptides (e.g., a common dosing system of 10% DMSO + 40% PEG300 + 5% Tween‑80 + 45% saline, as described in the instructions of multiple reagent companies). Animal and human toxicology data indicate relatively low systemic toxicity and immunogenicity; after oral or intravenous administration, it is mainly excreted unchanged in urine. In some eye drops, PEG300 serves as a nonionic lubricant to improve wetting of the corneal surface.