Polyethylene Glycol (PEG): Applications and Selection from Pharmaceutical Excipients to Industrial Lubrication

Polyethylene glycol (PEG) is a water-soluble polyether produced by polymerisation of ethylene oxide. It is graded by average molecular weight from 200 to over 20,000, with appearance changing continuously from a colourless transparent liquid (low MW) to a white waxy solid (high MW). Its combination of tunable molecular weight, excellent water solubility and low toxicity makes it a universal material across pharmaceutical, daily-chemical and industrial sectors.

Low-Molecular-Weight PEG (200–600): Liquids for Pharma and Lubrication

PEG200/300/400/600 are liquids, commonly used as suppository and ointment bases, soft capsule plasticisers and taste-masking solvents for oral liquids, and also as industrial lubricants, textile auxiliaries and paper dispersants. PEG400, with moderate viscosity and low irritation, is the most common grade in pharmaceutical and cosmetic applications.

Medium- and High-Molecular-Weight PEG (1000–20000): Solids for Bases and Sustained Release

PEG1000/4000/6000/8000 are solids, used as cream bases, suppository scaffolds, tablet binders and coatings, drug release carriers and hydrogels. The higher the molecular weight, the slower the water solubility and the stronger the film-forming ability, so selection must follow the process temperature and release curve.

Grades and Compliance: Pharmaceutical vs Industrial

Pharmaceutical excipients must comply with the Chinese Pharmacopoeia or EP/USP standards, with strict limits on heavy metals, ethylene glycol/diethylene glycol impurities and peroxides; industrial grades follow corporate standards focused on viscosity and hydroxyl value. When procuring, always state the grade, molecular weight range (nominal value ± tolerance) and intended use to avoid the compliance risk of substituting industrial grade for pharmaceutical grade.

Procurement Advice

Confirm the application (pharmaceutical / daily chemical / industrial), target molecular weight range and viscosity indicators, and require the supplier to provide the corresponding grade COA and batch stability data. Haiyu Zhonglong can provide specification sheets for PEG and other products with samples from 1kg/25kg. Submit an Online Inquiry or Contact Us; more products in the Product Centre.