PEG 400

CAS Number:

25322-68-3 (covers the PEG polymer series; specific grades like PEG 400 are often referenced by this number)

Chemical Name: 

Polyethylene Glycol (Average Molecular Weight 400). Also known as Macrogol 400

Molecular Formula:

H(OCH2CH2)nOH, where n averages 8-9 for PEG 400

Molecular Weight:

380 - 420 g/mol

Common Form:

Clear, colorless or slightly yellow, viscous, hygroscopic liquid. Odorless or with a faint, characteristic odor

Uses:

PEG 400 is prized for its excellent solvent properties, miscibility with water and many organics, low toxicity, and humectancy.

Primary Applications:

· Pharmaceuticals: A versatile solvent, co-solvent, and liquid vehicle for oral, topical, and parenteral (injectable) formulations. Used in elixirs, soft gelatin capsules, ointments, and as a laxative.

· Cosmetics & Personal Care: Acts as a humectant, solvent, and viscosity modifier in creams, lotions, toothpastes, and deodorants. Helps carry active ingredients and retain moisture.

· Chemical & Industrial: Used as a plasticizer, lubricant, and reaction medium in chemical synthesis. Also found in inks, dyes, and as a hydraulic fluid.

· Food Industry: Occasionally used as a humectant, dispersant, or carrier for flavors and colors.

What does PEG 400 do in a formulation?

• Solvent & Co-solvent: Its core function. Dissolves a wide range of both hydrophilic and moderately lipophilic substances, improving the solubility and stability of active ingredients.
• Humectant: Attracts and retains moisture from the air, preventing formulations from drying out.
• Plasticizer & Viscosity Modifier: Softens and adds flexibility to films (e.g., in capsule shells) and adjusts the flow properties of liquids and creams.
• Vehicle & Carrier: Provides a liquid base for delivering drugs or actives in a uniform dose.
• Lubricant: Reduces friction in mechanical applications and can provide a smooth feel on skin.

Safety Profile:

· Hazard Classification: Generally recognized as safe (GRAS) for specific uses but can be harmful if swallowed in large quantities (laxative effect). Classified as causing serious eye irritation.

· Toxicity: Low acute oral toxicity (LD?? > 30,000 mg/kg in rats). However, significant ingestion leads to osmotic diarrhea (its mechanism as a laxative).

· Skin/Eye Contact: Can cause eye irritation. Prolonged skin contact may lead to mild irritation due to its hygroscopic nature (drying effect).

· Metabolism & Impurities: The primary safety concern relates to potential impurities (ethylene oxide, 1,4-dioxane) from production and the metabolism of high doses. High-purity pharmaceutical grades minimize this.

· Required PPE: Safety glasses and gloves are recommended for routine handling to prevent eye contact and prolonged skin exposure.

· Storage: Store in airtight containers in a cool, dry place due to its hygroscopic nature.

Technical profile: