Polyethylene Glycol (PEG): A Versatile Polymer for Industry, Medicine, and Cosmetics

Technical Introduction

Polyethylene Glycol (PEG) is a polyether compound formed by the polymerization of ethylene oxide with water or ethylene glycol as an initiator. It is available in a wide range of molecular weights (e.g., PEG 200, PEG 400, PEG 6000), each with unique physical and chemical properties. PEG is highly valued for its water solubility, chemical inertness, lubricating properties, and biocompatibility.

• Chemical Name: Polyethylene Glycol

• Synonyms: PEG, Macrogol

• General Formula: H(OCH₂CH₂)ₙOH

• Molecular Weight Range: ~200 – 20,000+ g/mol (depending on grade)

• Appearance: Colorless liquid (low MW) or white waxy solid (high MW)

• Solubility: Freely soluble in water, ethanol, and many polar solvents

• Nature: Non-ionic, hydrophilic polymer

Applications

1. Pharmaceuticals & Medicine

• Used as solvents, ointment bases, and tablet binders.

• PEGylation: Attaching PEG chains to therapeutic proteins and drugs improves solubility, bioavailability, and stability.

• Acts as an osmotic laxative (PEG 3350).

2. Cosmetics & Personal Care

• Functions as an emollient, humectant, thickener, and solvent in creams, lotions, shampoos, and toothpaste.

• Improves texture and spreadability of formulations.

3. Food Industry

• Used as a solvent, anti-foaming agent, and food additive in certain regulated applications.

4. Industrial Uses

• Serves as a lubricant, dispersing agent, plasticizer, and humectant.

• Plays a role in ceramics, textiles, paints, and coatings.

• Used as a precursor in chemical syntheses.

5. Laboratory & Biotechnology

• Widely used in protein crystallization, DNA precipitation, and cell fusion experiments.

• PEGylated lipids are used in liposomal drug delivery systems.

✅ Advantages

• Highly water-soluble and miscible with many solvents.

• Non-toxic and biocompatible, suitable for medical use.

• Chemically stable and inert under most conditions.

• Customizable properties depending on molecular weight.

• Acts as a stabilizer, carrier, or excipient in formulations.

• Broad regulatory acceptance across pharmaceutical, cosmetic, and industrial applications.

⚙️ Technical Specifications (Typical Parameters)

⚠️ Safety & Regulations

• Generally Recognized as Safe (GRAS) by FDA for food and pharma use.

• Pharmaceutical grade (Macrogol) widely used in medicine.

• Toxicity: Very low; excessive ingestion may cause osmotic diarrhea or GI discomfort.

• Skin & Eye Contact: Generally safe; mild irritation possible at high concentrations.

• Environmental Safety: Biodegradable but should be disposed of according to regulations.

❓ FAQ

Q1: What’s the difference between PEG 400 and PEG 6000?
The number refers to average molecular weight. PEG 400 is a low-MW liquid, while PEG 6000 is a high-MW waxy solid with different solubility and thickening properties.

Q2: Is PEG safe in cosmetics?
Yes, PEGs are widely used in creams, shampoos, and skincare products. However, formulations must meet purity standards to avoid contamination with ethylene oxide or dioxane residues.

Q3: How does PEGylation improve drug performance?
PEGylation increases circulation time, stability, and solubility of therapeutic proteins and reduces immunogenicity.

Q4: Is PEG biodegradable?
Yes, PEG is biodegradable under aerobic conditions and is considered environmentally safe.

Q5: Can PEG be taken orally?
Yes. Certain grades (PEG 3350) are approved as laxatives for short-term constipation relief.