POLYETHYLENE GLYCOL (M W 200-9,500)

CAS: 25322-68-3 BOILER WATER ADDITIVE, FLAVORING AGENT OR ADJUVANT, FORMULATION AID, LUBRICANT OR RELEASE AGENT, SURFACE-ACTIVE AGENT

Polyethylene glycol (PEG) with an average molecular weight range of 200 to 9500 is a synthetic polymer used in food-related applications including formulation aid and surface-active agent, permitted under specific regulatory conditions in food additive and indirect food additive regulations.

What It Is

Polyethylene glycol (often abbreviated PEG) is a class of synthetic polymers composed of repeating ethylene oxide units, defined here by an average molecular weight range between 200 and 9500. These polymers are non-ionic in character, water soluble, and often colorless and odorless, allowing for versatile use across industrial, pharmaceutical, and food-related applications. In the context of food and food-contact uses, PEG falls into multiple technical function roles including as a formulation aid, surface-active agent, lubricant or release agent, and occasionally as a carrier or film coating component. The molecular weight range significantly influences physical properties, with lower molecular weight grades tending to be liquid at ambient conditions and higher grades being waxy solids. The designation "Polyethylene glycol (M W 200-9500)" corresponds to a family of homologous polymers rather than a single compound, and is referenced under regulatory frameworks in the United States Code of Federal Regulations (for example, in food additive and indirect food additive listings). These polymers are often identified by number (e.g., PEG-400, PEG-6000) that approximate their average molecular weight. The CAS number 25322-68-3 uniquely identifies this specific PEG range. In food applications, the polymer does not impart significant flavor or aroma, which supports its classification as a functional additive rather than a sensory ingredient, and its ability to modify surface and formulation characteristics is leveraged across a variety of food and supplement contexts. PEG is also recognized in chemical databases under other names such as macrogol, polyoxyethylene glycol, and poly(ethylene oxide), reflecting its polymeric nature and historical naming conventions.

How It Is Made

Polyethylene glycol polymers are manufactured through the controlled polymerization of ethylene oxide with water, typically in the presence of a basic catalyst. The process involves sequential addition of ethylene oxide to initiate polymer chain growth, where the number of repeating units determines the average molecular weight of the resulting PEG. Once the targeted molecular weight is achieved, the reaction is terminated through neutralization of the catalyst. The resulting polymer mixture is purified to remove residual monomers, catalysts, and low‑molecular‑weight byproducts. Industrial production of PEG requires careful control of reaction conditions to achieve the desired molecular weight distribution, since this influences viscosity, melting or flow temperature, and solubility. High purity grades intended for food or pharmaceutical use undergo additional refinement to meet regulatory and technical standards for safety and performance. For example, strict limits on ethylene oxide and related impurities are enforced by analytical methods prescribed in regulatory monographs to ensure safety. Manufacturing facilities producing PEG for food applications typically adhere to good manufacturing practices (GMP) and detailed specification criteria that cover identity, composition, and impurity thresholds. Although the core chemistry of PEG production is well established, specific proprietary catalyst systems, process configurations, and control strategies may vary among manufacturers. At a high level, all processes share the common polymerization mechanism and require rigorous quality control to deliver consistent, food‑grade material meeting specification requirements.

Why It Is Used In Food

In food and food supplement manufacturing, polyethylene glycol is valued for its functional versatility. It can act as a lubricant or release agent, helping prevent sticking of powders or tablets to processing equipment. As a formulation aid, PEG improves mixing and consistency of multi‑component blends, supporting uniform distribution of minor ingredients. It also functions as a surface‑active agent or solvent, enhancing wetting and dispersion of certain components in complex formulations. PEG grades within the 200–9500 molecular weight range can serve as carriers or coating materials for tablets, dragees, and encapsulated nutrients or supplements, aiding in delivering active agents with desirable release or stability characteristics. Its water solubility and compatibility with a wide range of other ingredients allow formulators to tailor texture and processing performance without introducing taste or odor that would alter the sensory profile of the final product. Because PEG does not contribute flavor itself but modifies the physical environment of the formulation, its use spans multiple categories from food supplement tablets to surface coatings on certain food contact materials. These functions support consistent product quality, extended shelf life of certain formats, and controlled interactions between the product and processing equipment or packaging. Overall, PEG is selected in food-related applications when control over moisture, equipment release, or physical form stability is required without undermining product acceptability.

Adi Example Calculation

To illustrate how an acceptable daily intake (ADI) might be interpreted, consider a hypothetical body weight and an ADI value from an authoritative body. For example, using a midpoint of an ADI range to illustrate the concept, if an ADI were described as up to a certain mg per kg body weight per day, you can calculate the corresponding daily amount for a given individual’s body weight. For a person weighing 60 kg, an ADI of X mg per kg body weight per day would translate to a total allowable intake of (60 kg multiplied by X mg per kg) per day. In application, food safety assessments compare likely dietary exposures to this calculated value to ensure typical consumption patterns remain well below the ADI, maintaining a margin of safety. This illustrative calculation is not a recommendation or specific advice but demonstrates how regulatory ADI values are operationalized for different body weights. Actual ADI values and associated regulatory guidance are determined by expert committees based on available scientific data. These values are used by regulators and industry to set conditions of use, ensure compliance, and support consumer safety.

Safety And Health Research

Safety assessments of polyethylene glycol by international authorities such as JECFA and EFSA have focused on toxicological data across a range of molecular weights and use scenarios. Studies compiled for regulatory review include evaluations of absorption, distribution, metabolism, and excretion, as well as various toxicity endpoints in animal models. These data inform regulatory bodies about potential hazards and safe exposure levels, with attention to differences in absorption across molecular weight grades. The Joint FAO/WHO Expert Committee on Food Additives conducted evaluations of polyethylene glycols and assigned an acceptable daily intake range based on available toxicological evidence. Their assessments consider oral exposures expected from food and supplement uses, and they weigh data from subchronic studies, general toxicity studies, and other relevant research. On the basis of comprehensive review of available evidence, international bodies have concluded that PEG used within regulated conditions is not a safety concern for consumers. EFSA has also reviewed available data and performed exposure assessments, particularly for uses in food supplements. Their refined exposure evaluation considered realistic use levels reported by industry and compared calculated dietary exposures to previously established group acceptable daily intake values. The conclusion was that typical exposures remain below levels of concern when PEG is used according to authorized conditions, reinforcing the body of evidence supporting safety. Ongoing monitoring by regulators includes attention to potential impurities and manufacturing consistency, ensuring that products labeled as polyethylene glycol meet the purity specifications required for food applications. While research continues to refine understanding of specific polymer behavior in biological systems, the current consensus in regulatory safety evaluations supports the controlled use of PEG in food-related applications.

Regulatory Status Worldwide

In the United States, polyethylene glycol (mean molecular weight 200–9500) is specifically listed in Title 21 of the Code of Federal Regulations as a permitted food additive under section 172.820, where conditions for identity and impurity limits are prescribed. It also appears in regulatory listings for indirect food additives and components of food contact materials, affirming that under defined conditions its use is authorized in food processing and related applications. These regulatory references indicate that PEG is recognized within the federal food additive framework when used as intended and meeting specified purity criteria. For example, CFR sections such as 172.820 cover direct food additive uses with compositional requirements, while indirect additive sections like 178.3750 allow its use in articles intended to contact food. In the European Union, polyethylene glycol is identified by the food additive number E1521 in regulatory databases of authorized food additives, and it is subject to defined conditions of use and purity standards in Annex II and III to Regulation (EC) No 1333/2008. EFSA has performed refined exposure assessments focused on uses in food supplements, noting that exposure estimates remain within previously established group acceptable daily intake ranges when used in accordance with regulations. This confirms that PEG is permitted for specific uses in the EU, and authorities periodically review exposure and safety data to ensure continued compliance. Internationally, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) evaluated polyethylene glycols and allocated an acceptable daily intake range, reflecting a long‑standing international assessment of safety. These regulatory frameworks collectively demonstrate that PEG is accepted for food and food‑contact applications worldwide when used within prescribed conditions, supported by technical specifications and safety evaluations.

Taste And Functional Properties

Polyethylene glycol is generally considered neutral in taste, with minimal if any inherent flavor for food applications. In lower molecular weight forms that are liquid under ambient conditions, PEG may exhibit slight viscosity characteristics that can influence mouthfeel when present at higher levels, but its use in food formulations is typically at concentrations where perceptible taste is negligible. Functionally, PEG behaves as a hydrophilic polymer that interacts favorably with water and other polar ingredients. This makes it useful in modifying viscosity, enhancing solubility of certain components, and serving as a humectant in formulations where moisture control is needed. It also acts as a surface-active agent, helping reduce surface tension and supporting even wetting and distribution of ingredients in complex blends. Thermal stability of PEG varies with molecular weight, with higher molecular weight grades maintaining solid or semi-solid structure at room temperature but melting at moderate temperatures. In processing conditions involving heat, these properties can be leveraged to influence flow and coating characteristics. Its stability across a range of pH values and compatibility with many food ingredients make PEG a robust option for applications where formulation integrity is critical. Although PEG does not impart aroma or flavor, its presence can affect texture, lubrication, and handling characteristics during both manufacturing and consumption, making it a practical choice for technical roles in product design.

Acceptable Daily Intake Explained

An acceptable daily intake (ADI) is a measure used by food safety authorities to indicate the amount of a substance that can be consumed every day over a lifetime without appreciable risk to health. The concept is rooted in toxicological studies that identify a no-observed-adverse-effect level in animal studies, which is then divided by safety factors to account for uncertainties and differences between species. For polyethylene glycols evaluated by international expert committees, the ADI range reflects consideration of data across multiple studies and grades of the polymer. This range acts as a guide for regulators and industry to ensure that typical exposures from food and supplement uses stay within levels deemed safe based on current scientific evidence. It is important to note that an ADI is not a recommended target intake; rather, it provides a boundary below which long-term exposure is considered to pose low risk. When regulatory bodies such as JECFA or EFSA describe an ADI or group ADI for PEG, they account for the range of molecular weights and use patterns, and incorporate conservative assumptions about consumption. Regulatory standards for manufacturing and purity also contribute to ensuring that products containing PEG comply with conditions that limit exposure to impurities that could otherwise affect safety.

Comparison With Similar Additives

Polyethylene glycol shares functional roles with other polymeric and surface-active food additives, though differences in molecular structure and properties influence specific applications. For example, glycerol and propylene glycol are low molecular weight polyols that also serve as humectants and solvents, helping retain moisture and improve ingredient solubility. Unlike PEG, these compounds are typically liquids across relevant functional grades and have distinct viscosity and sweetness profiles. Another related group includes polysorbates, which are ethoxylated sorbitan esters used as emulsifiers in food systems. While both PEG and polysorbates exhibit surface-active behavior, polysorbates are specifically optimized for stabilizing oil‑in‑water emulsions, whereas PEG’s roles are broader and include formulation aid and lubricant applications. The structural difference—PEG’s linear ether backbone versus polysorbates’ esterified and ethoxylated structure—leads to distinct performance and regulatory profiles. Cellulose ethers, such as methylcellulose or hydroxypropyl methylcellulose, also function as thickening and stabilizing agents in food systems. These derivatives of cellulose provide viscosity modification and gel formation properties that differ from PEG’s primarily hydrophilic and surface interaction roles. Such comparisons highlight how different classes of additives contribute to formulation targets, with PEG focusing on film formation, lubrication, and surface activity rather than thickening or gelation.

Common Food Applications Narrative

Polyethylene glycol is encountered in a variety of food and food supplement applications, where it plays behind‑the‑scenes functional roles that support product quality and processing efficiency. In dietary supplement tablets and capsules, it is used as a film coating agent that helps improve appearance, control moisture migration, and ensure consistent release of active ingredients. These coatings can contribute to a smooth, glossy finish on tablets and aid swallowing without contributing taste. In confectionery and other compressed formats, PEG can serve as a lubricant during tableting, helping powders flow through dies and reducing friction that can lead to capping or sticking. Its water‑soluble nature assists formulators in producing consistent blends that hold together under mechanical stress yet dissolve predictably when consumed. Food contact materials such as certain packaging components or processing aids may incorporate PEG as a release or surface treatment, supporting ease of handling and reducing residue transfer on equipment surfaces. In complex powdered mixes, it may help bind or disperse ingredients that would otherwise form clumps, improving texture and ease of reconstitution. Across these broad categories, consumers are unlikely to see PEG listed prominently on packaging beyond its inclusion in an ingredient list for supplements or processed foods. Its contribution is primarily technical, ensuring that the product reaches the consumer with intended quality attributes such as texture, appearance, or stability. While PEG does not add nutritional value or sensory character, it supports the performance of modern food and supplement formulations in measurable ways.

Safety & Regulations

FDA

  • Approved: True
  • Regulation: 21 CFR 172.820

EFSA

  • Notes: Specific numeric ADI not confirmed from d EFSA source
  • Approved: True
  • E Number: E1521

JECFA

  • Year: 1979
  • Ins Number: 1521
  • Adi Display: 0-10 mg per kg bw
  • Adi Mg Per Kg: 10

Sources

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