Polyethylene Glycol (PEG): Properties, Applications Across Multiple Fields, and Product Selection Guide

I. Overview

Polyethylene glycol (PEG) is a family of linear polyether polymers produced by the stepwise addition polymerization of ethylene oxide with water or ethylene glycol. Its general formula is:

HO–(CH₂CH₂O)ₙ–H

PEG typically appears as a colorless or slightly yellow liquid, paste, or solid, and has the following characteristics:

1. Excellent water solubility and hydrophilicity:

Highly soluble in water and readily miscible or compatible with many organic solvents.

2. Good compatibility:

Shows good miscibility with a wide range of organic ingredients, active pharmaceutical ingredients (APIs), and formulation systems.

3. Low toxicity and mild irritation:

When used within compliant dose ranges and under appropriate application conditions, PEG is generally regarded as having good biocompatibility.

4. Excellent lubricating, moisturizing, dispersing and adhesive properties.

5. Nonionic nature:

PEG is nonionic and has minimal impact on system pH, allowing formulation pH to be adjusted over a relatively broad range.

Thanks to these properties, PEG is used extensively in pharmaceuticals, cosmetics, chemical fibers, rubber, plastics, papermaking, paints, electroplating, agrochemicals, metalworking, food processing and many other fields.

II. Applications of PEG in the Pharmaceutical Field

In many dosage forms, PEG can serve not only as a base and excipient, but also as a solvent, solubilizer, or process aid.

2.1 Ointment and Gel Bases

Mixtures of PEGs with suitable molecular weights and ratios can form semi-solid bases with ointment-like consistency. For example, a 1:1 mixture of PEG 300 and PEG 1500 is a commonly used hydrophilic ointment base. Its main characteristics include:

1. Good water solubility and drug compatibility:

Readily miscible with many APIs and suitable for preparing hydrophilic ointments, gels and related dosage forms.

2. Light color and stable appearance:

Intrinsically light in color, exerting little influence on product appearance, and not prone to spoilage or rancidity.

3. Easy to wash off:

Ointments formulated with PEG bases can be easily removed from skin, hair, and fabrics due to their good solubility in water.

4. Does not impede perspiration:

When relatively soft PEG bases are applied to the skin surface, they generally do not significantly interfere with normal sweating.

5. Moderate water absorption:

PEG products have some water absorption and surface-drying capability, making them useful for treating exudative inflammatory conditions, eczema and dermatitis.

6. Good compatibility with actives:

Compatible with a wide variety of topical drugs, antimicrobial agents and anti-inflammatory ingredients. Even when certain drugs have limited solubility, performance can often be optimized by adjusting the drug-to-base ratio.

7. Nonionic characteristics:

PEG itself does not ionize, so the pH of the formulation can be adjusted as needed.

8. Good storage stability:

PEG-based ointment vehicles are generally stable during long-term storage under appropriate conditions.

2.2 Suppository Bases

When used alone or in combination, PEG 1000–4000 can serve as suppository bases with stable melting points and good storage properties, owing to their good water solubility and tunable melting/softening ranges. Compared with conventional fatty bases:

1. Their melting points are more stable and they are less likely to soften or deform with changes in ambient temperature.

2. Their dissolution behavior is adjustable, which is advantageous for controlling drug release.

3. They are suitable for drugs that are poorly released from fatty bases.

The irritancy of suppositories to mucosal tissue depends on the overall formulation. The actual level of irritation needs to be evaluated comprehensively with respect to the drug type, dose and site of administration.

2.3 Solvent and Solubilizer in Liquid Preparations

PEG is an excellent solvent and solubilizer and can be used in:

1. Oral liquid preparations and oral drops.

2. Certain topical drops and sprays.

3. Situations where vegetable oils are not suitable as carriers for active ingredients, in which case PEG is often selected as an alternative solvent.

Parenteral preparations containing PEG typically exhibit good stability and safety under conventional steam sterilization conditions (e.g., about 121 °C), which underpins its use in injections and certain specialized dosage forms.

2.4 Tablets and Film-Coated Preparations

High-molecular-weight PEGs (e.g., PEG 4000, PEG 6000) have multiple functions in solid dosage forms:

1. Tablet binder and processing aid:

a) Provide a certain degree of plasticity, facilitating granulation and tablet compression.

b) Improve the mechanical strength of tablets, making them less prone to chipping and breakage.

2. Modulation of drug release and disintegration:

a) PEGs are highly soluble in water, and high-molecular-weight PEGs can have water solubility above 50%, promoting water penetration into the tablet core and facilitating drug release.

3. Film coating and coating systems:

a) Finely milled pharmaceutical-grade PEG (e.g., 100–300 mesh) is suitable for film-coating processes and can be used as part of the film-forming system or as a plasticizer.

b) It imparts a smooth, glossy surface to tablets, improving both appearance and swallowability.

4. Anti-tacking effect:

a) Small amounts of PEG 4000 or PEG 6000 can reduce sticking between sugar-coated or film-coated tablets, and between tablets and the inner wall of the container.

III. Applications of PEG in Personal Care and Cosmetics

In cosmetic formulations, PEG (particularly PEG 4000, PEG 6000, etc.) is used as a neutral component. Its main advantages include:

(1) Excellent water solubility and hydrophilicity;

(2) Non-volatile, non-oily, with a light, non-greasy skin feel;

(3) Good affinity for the skin;

(4) Light color and mild odor;

(5) Low toxicity and relatively low irritation.

By varying the molecular weight, the consistency (viscosity) and hygroscopicity of PEG can be adjusted, making it suitable for a wide range of creams, lotions and cleansing products. Typical uses include:

1. Carrier and Solubilizer

(a) As a non-volatile carrier for deodorants and fragrances;

(b) As a neutral fragrance fixative, helping slow down fragrance evaporation and prolong fragrance longevity;

(c) As an evaporation retardant in nail polish removers;

(d) As a solubilizer or lubricant in lipsticks and other solid/semi-solid color cosmetics.

2. Rheology and Skin-feel Modulation

(a) As a consistency modifier in toothpaste formulations, helping to improve extrudability and storage stability;

(b) Used in shampoos, facial cleansers, shaving foams, depilatory products, etc., to adjust system viscosity and enhance lubricity and slip during use.

3. Non-oily Lubrication and Antistatic Performance

(a) Used in pre- and post-shave care products as a non-oily lubricant;

(b) Used in hair sprays and other hair-care products, where it provides both softening and antistatic effects.

4. Soap Making and Solid Cleansing Products

(a) In soap-making processes, PEG can be used as an auxiliary additive, acting as an emulsification aid and plasticity promoter to improve molding performance and help maintain sharp, well-defined bar shapes;

(b) It helps retain fragrance, reduces cracking and breakage of soap, and improves foam fineness and skin feel;

(c) It can also be used as a binder and excipient in tablet-type bathroom cleaners, shampoo bars, denture cleaning tablets and similar solid products.

IV. Applications of PEG in Functional Materials and Industrial Formulations

4.1 Coatings and Inks

In coating systems:

(1) Low-molecular-weight PEG can act as an effective dispersant and wetting agent, promoting the dispersion of pigments and fillers;

(2) High-molecular-weight PEG contributes to improved film-forming properties and can enhance the flexibility and gloss of the coating film to a certain extent;

(3) Coatings formulated with PEG as a base component or auxiliary often show improved water resistance and application properties compared with purely water-based systems;

(4) High-molecular-weight PEG can also be used as an evaporation-retarding component in paint strippers, helping to control evaporation rate.

In inks, PEG and its fatty acid esters are widely used because of their good solubility and lubricity, and are commonly found in various ink formulations, particularly those for stencil duplicating paper, stamp pad inks and ballpoint pen inks.

4.2 Textile Industry

PEG and PEG esters are mainly used in the textile industry as:

(a) Lubricants and softeners in spinning and weaving processes;

(b) Antistatic agents to reduce static buildup during processing and wearing;

(c) Dispersants and dye carriers in dyeing processes, helping to promote dye uptake and level dyeing;

(d) Components of air-conditioning and finishing formulations, improving the hand feel and appearance of fabrics.

4.3 Rubber and Cork Products

PEG has strong affinity for rubber without readily causing rubber degradation, and it has low volatility and a relatively high flash point. As a result, it is widely used in rubber and cork products:

(1) As a mold-release and loosening agent for rubber and polyurethane products (such as soles, heels, radiator hoses, etc.), helping products to be released from molds quickly;

(2) As a lubricant during latex application to fiber surfaces and during latex coagulation;

(3) In SBR (styrene–butadiene rubber) and similar systems, addition of an appropriate amount of PEG can improve processing performance and slow down aging to some extent;

(4) In cork and sponge, the low volatility and water-holding capacity of PEG make it an effective plasticizer/humectant, helping to maintain elasticity and softness.

4.4 Resins and Plastics

Because of its good water solubility and compatibility, incorporation of PEG into many resin systems can significantly improve performance:

(1) Applicable to alkyd resins, methacrylic resins, polyurethane resins and certain natural resin systems;

(2) Partial replacement of polyols (such as glycerol) with PEG can increase resin toughness and flexibility;

(3) For natural resins such as shellac, introducing PEG can yield modified resins with better water solubility or water dispersibility;

(4) In polyurethane resins, adding PEG can enhance material strength and elasticity and impart higher surface gloss;

(5) In resin coatings, low-molecular-weight PEG readily dissolves resins, while high-molecular-weight PEG helps improve dry-film properties.

In the plastics industry, PEG is mostly used as an auxiliary additive, for example:

(1) As an internal or external lubricant in extrusion and injection-molding processes;

(2) As a mold-release agent during molding;

(3) PEG fatty acid esters are effective plasticizers and antistatic agents in PVC and other plastic products.

The high-temperature stability, low toxicity and good miscibility of PEG with PVC products make it highly valuable in many plastic formulations.

4.5 Metalworking

Due to its good water solubility, lubricity and low volatility, PEG also has multiple uses in metalworking:

(1) As a key component of metal cooling and lubricating fluids for cutting, stamping, drawing and other operations;

(2) Suitable for water-soluble lubrication systems used in machining hollow castings or workpieces with complex geometries;

(3) As a component of auxiliary solvents or fluxes in low-temperature soldering;

(4) High-molecular-weight PEG can be used as a binder and forming aid in powder metallurgy, lapping pastes and polishing materials.

4.6 Papermaking and Packaging Industry

(1) PEG 300 can be used as a special plasticizer and softener in the production of cellulosic tape materials;

(2) In paper grades requiring low moisture content but needing a certain level of softness and lubricity, PEG can increase the softness and smoothness of the paper;

(3) It can be used as a plasticizer for packaging boards and can partially replace traditional plasticizers in certain adhesive systems to improve flexibility and workability.

V. PEG as a Chemical Intermediate and Its Other Uses

5.1 Intermediate for Nonionic Surfactants

PEG of all molecular-weight ranges is an important chemical raw material and intermediate, particularly in the manufacture of nonionic surfactants:

(a) PEG fatty acid esters, obtained by reaction of PEG with fatty acids, constitute a major class of nonionic surfactants;

(b) PEG copolymers (e.g., copolymers with propylene oxide) are also widely used in products such as emulsifiers, wetting agents, and defoamers.

Applications of these PEG derivatives include:

1. Emulsifiers in the food industry (subject to relevant regulations and safety assessments);

2. Emulsifiers and wetting agents in textile oils;

3. Emulsifiers and dispersants in agrochemical, pharmaceutical and cosmetic formulations;

4. Dispersants, wetting agents and antistatic agents in the plastics industry;

5. Dispersants, wetting agents and anti-redeposition agents in cleaning formulations.

5.2 Other Typical Uses

PEG and its derivatives also have a variety of uses in other fields, for example:

(a) Functional components in dust removers and specialty cleaners;

(b) Components of heat-transfer fluids used at temperatures below approximately 200 °C;

(c) Performance modifiers in ultra-soft polyurethane foams;

(d) Plasticizers and forming aids in ceramic slurries and ceramic molds;

(e) Carriers and solvents for agricultural insecticides, improving application properties and dispersibility;

(f) Complexing agents or solubilizing aids for polyhydroxy phenols and similar substances in certain systems.

VI. Summary

Polyethylene glycol (PEG), a family of structurally simple yet highly versatile hydrophilic polymers, plays an indispensable role in numerous fields, including pharmaceutical formulations, personal care and cosmetics, coatings and inks, textiles, rubber and plastics, metalworking, papermaking and packaging, as well as surfactant production.

Overall, PEG offers:

(1) Excellent water solubility and compatibility

(2) Outstanding lubricating, moisturizing, dispersing and adhesive properties

(3) Nonionic character and relatively low toxicity

(4) Tunable physicochemical properties via molecular-weight selection

PEG and its derivatives are not only important functional additives, but also key chemical intermediates. In practical applications, the molecular weight and dosage should be selected rationally based on the intended use, target user population and regulatory requirements, so as to maximize performance benefits while ensuring product safety and regulatory compliance.

Aladdin Polyethylene Glycol (PEG) Product Recommendations

Molecular weight / type & grade overview	Aladdin catalog No.	Recommended key application areas
PEG 200, synthetic grade / UltraBio grade	P615517 (for synthesis, 200), P103718 (Mn ≈ 200), P615490 (UltraBio™, 200)	Low-viscosity hydrophilic solvent and solubilizer; suitable as a carrier in liquid formulations, cosmetic solvent, and in coatings/inks and metalworking fluids; UltraBio grade is suitable for biological and pharmaceutical R&D systems.
PEG 300 (pharmaceutical grade, synthetic grade, Kollisolv brand)	K432453 (Kollisolv® PEG E 300), P774683 (PharmPure™, GMP pharmaceutical grade), P432446 (PharmPure™ pharmaceutical grade), P615502 (for synthesis, 300), P103728 (Mn ≈ 300)	Pharmaceutical grade: for ointment base blends, adjusting melting point in suppositories, and as a solubilizer in oral/topical liquid formulations; in personal care, used as humectant, lubricant and solvent; synthetic grade is suitable for industrial formulations (coatings, inks, metalworking fluids, etc.).
PEG 400 (pharmaceutical grade, synthetic grade, Kollisolv)	K432452 (Kollisolv® PEG E 400), P774684 (PharmPure™ pharmaceutical grade), P432449 (PharmPure™ pharmaceutical grade), P615526 (for synthesis, 400), P103737 (Mn ≈ 400), P615470 (UltraBio™, 400)	A classic hydrophilic solvent/solubilizer: suitable for suppositories, oral liquids and topical preparations; widely used in cosmetics (creams, shampoos, facial cleansers, toothpaste). Synthetic/UltraBio grades are used in coatings, inks, metalworking fluids, polyurethane formulations and biological experiments.
PEG 600 (synthetic grade / UltraBio)	P615532 (for synthesis, 600), P103727 (Mn ≈ 600), P615496 (UltraBio™, 600)	Slightly higher viscosity; suitable as part of hydrophilic ointment/gel bases, humectant in cosmetic creams, textile lubricant/softener, and resin plasticizer. UltraBio grade is suitable for biological and pharmaceutical R&D.
PEG 800 (general grade)	P103726 (Mn ≈ 800)	Intermediate between 600–1000; can be used in ointments, creams and cosmetic emulsions, and as an excipient in certain suppositories and tablets; also suitable as plasticizer/lubricant in industrial formulations.
PEG 1000 (pharmaceutical grade, synthetic grade, UltraBio)	P615506 (for synthesis, 1000), P103719 (Mn ≈ 1000), P432422 (UltraBio™, 1000), P432421 (PEG solution 50% in H₂O, 1000, UltraBio™, molecular biology grade), P615477 (UltraBio™, 2000; often used in the same application range)	In pharmaceuticals and cosmetics: used in ointments, suppository bases (in combination with lower-MW PEGs), as tablet binder and film-coating excipient. UltraBio/molecular biology grades are suitable for cell fusion, PEG precipitation and biotherapeutic R&D.
PEG 1450–1500 (pharmaceutical grade, synthetic grade, solution grade)	P432442 (PEG 1500, PharmPure™ pharmaceutical grade), P615460 (PEG 1500 solution), P615515 (synthetic grade 1500), P103721 (Mn ≈ 1500), P615455 (average mol wt 1,450), P615500 (UltraBio™ 1500), P615453 (50 % (w/v), average mol wt 1,450, sterile-filtered, BioReagent, suitable for hybridoma)	Typical molecular-weight range for ointment/suppository bases and for tablet binders and film coatings. Pharmaceutical grade is suitable for commercial formulation manufacture; BioReagent/UltraBio grades are suited to pharmaceutical and biological R&D; also useful in cosmetic creams and resin plasticization.
PEG 2000 (synthetic grade, UltraBio)	P615519 (for synthesis, 2000), P103723 (Mn ≈ 2000), P615477 (UltraBio™, 2000)	Widely used in tablet film coatings, certain controlled-/sustained-release formulations, cosmetic creams and lotions, and as a plasticizer/film-forming aid in coatings and resins. UltraBio grade is suitable for biopolymer modification and PEGylation R&D.
PEG 3000 / 3350 (pharmaceutical grade, synthetic grade, BioReagent / UltraBio)	P432448 (PEG 3000, PharmPure™ pharmaceutical grade), P615522 (synthetic grade 3000), P432429 (Mn ≈ 3350), P432418 (BioReagent Plus, Mn ≈ 3350), P432424 (UltraBio™, 3350)	Pharmaceutical grade: used in tablet film coatings, suppository and ointment bases, and as a binder in granulated formulations. High-purity grades are commonly used for biological sample precipitation (e.g. PEG 3350 for protein/nucleic acid precipitation) and as buffer additives. In industry, used as resin plasticizer and film-forming aid in coatings/inks.
PEG 4000 (pharmaceutical grade, synthetic grade, UltraBio)	P432443 (PharmPure™ pharmaceutical grade 4000), P615530 (synthetic grade 4000), P103724 (Mn ≈ 4000), P103724-MGI (Mn ≈ 4000, high-conductivity specification), P615468 (UltraBio™, 4000)	The typical molecular weight discussed above for tablet binders/film-formers, suppository bases and ointment bases. Also used to improve dry-film properties in coatings, as plasticizer and antistatic agent in resins, and for lubrication and toughening in rubber/plastics. UltraBio grade is suitable for biomolecule precipitation and buffer preparation.
PEG 6000 (pharmaceutical grade, synthetic grade, UltraBio)	P432444 (GMP, PharmPure™, pharmaceutical grade 6000), P103725 (Mn ≈ 6000), P615504 (synthetic grade Mn 6000), P615486 (UltraBio™, 6000), P432426 (UltraBio™, 6000)	In pharmaceuticals: used for tablet film coatings, sustained-release layers, suppository and ointment bases. In industry: enhances coating film durability and resin toughness, and is used as a paper strength agent and in textile sizing/softening. UltraBio grade is suitable for protein/nucleic acid precipitation, crystallization and as a buffer additive.
PEG 8000 (BioReagent / UltraBio / solution)	P274350 (BioReagent 8000), P103734 (Mn ≈ 8000), P432417 (40% in H₂O, 8000), P615464 (UltraBio™, 8000), P748949 (BioReagent DNase, RNase free Protease Free ≥99% 50%) P432427 (UltraBio™, molecular biology grade, 8000)	High-molecular-weight PEG commonly used in sustained-release/gel-type formulations, tablet matrix systems, film formation and thickening in coatings and resins, plasticization of rubber and cork, and as papermaking/textile auxiliary. BioReagent/UltraBio/RNase-free grades are classic choices for protein and nucleic acid precipitation, cell fusion and PEG-mediated transformation.
PEG 10000 (synthetic grade / UltraBio / BioReagent)	P615512 (synthetic grade 10000), P103731 (Mn ≈ 10000), P598941 (UltraBio™, Mn ≈ 10000)	Higher-molecular-weight PEG suitable as thickener and film-forming aid in resins, coatings and inks, and as a plasticizer in plastics. In pharmaceutical R&D and biological fields, it is often used for PEG precipitation, sustained-release formulations and high-polymer material modification.
PEG 20000 / 35000 (high-molecular-weight PEG)	P103730 (Mn ≈ 20000), P615480 (UltraBio™, 20000), P432416 (35000), P432425 (UltraBio™, 35000)	Mainly targeted at high-polymer materials and industrial formulations: used in resins, coatings, inks, adhesives, as thickeners and paper strength enhancers. Can also be used to prepare high-gel-strength pharmaceutical excipient systems or sustained-release matrix materials.
Medium- to high-molecular-weight PEG range (general Mn products 800–6000)	P103726 (800), P103727 (600), P103719 (1000). P103721 (1500), P103723 (2000), P103725 (6000), P615457 (Mn ≈ 2050 chips), etc.	This series of Mn products without specially designated grades can be used flexibly for: excipient screening in pharmaceutical R&D, cosmetic formulation development, modification of resins/plastics/rubber, and lab-to-pilot scale-up work.
BioReagent / UltraBio™ PEG series	P748949, P274350, P432421, P615453, P598941, P615477, P615496, P432424, P432427, P615480, P615486, P615470, P615464, P615490, P432426, P615494, P615468, P432422, P615500, P432425, P432418, etc.	Common features: high purity, low impurity levels; some grades are RNase/DNase-free or molecular biology grade. Very suitable for drug discovery, molecular biology, cell fusion, PEG precipitation, protein/nucleic acid purification, etc. These can be broadly classified as “PEG for pharmaceutical and high-end industrial formulations.”
Tetraethylene glycol	T595684 (tetraethylene glycol ≥ 96%)	Low-molecular-weight polyether solvent: suitable as a solvent for organic synthesis, as a cosolvent in coatings and inks, and as a component of metalworking fluids.
Poly(ethylene oxide) (high-Mv PEO)	P432436 (Mv ≈ 8,000,000), P432437 (Mv ≈ 900,000), P615493 (viscosity 65–115 cps), P432440 (Mv ≈ 400,000)	Essentially ultra-high-molecular-weight polyethylene glycol/poly(ethylene oxide). Suitable as thickener, film-forming agent, adhesive, paper strength enhancer, textile sizing and softening agent, and as a tackifier/anti-sagging aid in coatings and inks. These are ideal companion products for the “Resins and Plastics,” “Papermaking and Packaging,” “Textiles,” and “Coatings and Inks” application sections described in this article.

Aladdin: https://www.aladdinsci.com/