Polyglyceryl-2 Monoisostearate

Polyglyceryl-2 Monoisostearate – Balanced Non-Ionic Emulsifier for Stable Cosmetic and Pharmaceutical Emulsions

Basic Information

• INCI Name: Polyglyceryl-2 Isostearate (Monoisostearate)

• CAS Number: 73296-86-3 (general for polyglyceryl isostearates; specific grade may vary)

• Synonyms: Diglyceryl monoisostearate, Polyglycerol-2 monoisostearate, PG-2 Monoisostearate

• Appearance: Pale yellow to amber viscous liquid or waxy solid

• HLB Value: Low to medium (suitable for W/O and O/W emulsions)

• Solubility: Soluble in oils and organic solvents; dispersible in water

• Storage: Store in tightly sealed containers in a cool, dry place, protected from light and moisture

Overview
Polyglyceryl-2 monoisostearate is a non-ionic monoester produced by the selective esterification of polyglycerin-2 (diglycerin) with one molecule of isostearic acid. This structure provides an optimal balance between hydrophilic (remaining hydroxyl groups) and lipophilic (isostearyl chain) fractions, making it an effective emulsifier and stabilizer for both water-in-oil (W/O) and oil-in-water (O/W) emulsions. It is mild, biocompatible, and biodegradable, derived from renewable plant-based sources.

Chemical Structure and Synthesis
The synthesis involves the reaction of one equivalent of isostearic acid with polyglycerin-2:
PG₂ + Isostearic Acid → Polyglyceryl-2 Monoisostearate + H₂O
where PG₂ denotes polyglycerin-2 (diglycerin). The retention of free hydroxyl groups ensures water compatibility, while the isostearyl chain provides lipophilicity, enabling effective interfacial activity.

Key Properties

• Non-ionic – compatible with a wide range of ingredients and pH levels.

• Amphiphilic – reduces interfacial tension, stabilizing both W/O and O/W emulsions.

• Balanced hydrophilic-lipophilic profile – ensures emulsion stability and uniformity.

• Good skin compatibility and mildness – suitable for sensitive skin.

• Excellent emulsifying and dispersing properties.

• Thermal and chemical stability – resistant to hydrolysis and oxidation.

• Biocompatible and low toxicity – safe for topical applications.

• Biodegradable and derived from renewable plant-based sources.

• Provides smooth, elegant textures and enhances skin feel.

Applications

• Cosmetics and personal care: Used as a primary or co-emulsifier, emollient, thickener, and stabilizer in W/O and O/W creams, lotions, serums, sunscreens, makeup removers, lip cosmetics, and hair care products. Provides stable, elegant textures with good spreadability, moisturizing properties, and skin conditioning.

• Pharmaceuticals: Employed as an emulsifier, solubilizer, and penetration enhancer in topical ointments, creams, and suppositories for uniform distribution of active ingredients.

• Industrial: Applied as a dispersant, lubricant, and stabilizer in specialty chemical formulations.

Key Benefits

• Effective emulsification for both W/O and O/W systems.

• Mild and non-irritating – suitable for sensitive skin and baby products.

• Emollient properties – softens and conditions skin and hair.

• Excellent spreading and moisturization.

• Thermal and chemical stability – reliable performance over time.

• Biocompatible, biodegradable, and of natural origin.

• Compatible with a wide range of cosmetic, pharmaceutical, and industrial ingredients.

• Acts as a co-emulsifier, thickener, and stabilizer in complex formulations.

Recommended Use
Typical usage levels range from 1–5% of the formulation, depending on the desired emulsion stability, viscosity, and texture. For optimal performance, dissolve in the oil phase at elevated temperatures (60–70°C) before emulsification. Can be combined with co-emulsifiers and thickeners for tailored rheology.

Safety and Handling

• Generally recognized as safe for use in cosmetics and personal care at recommended concentrations.

• Low irritation potential; well-tolerated by skin and mucous membranes.

• Avoid contact with strong oxidizers and acids.

• Store in a cool, dry place, away from direct sunlight.

• Use appropriate personal protective equipment (gloves, safety goggles) when handling.

Quality Assurance
Each batch is tested for acid value, saponification value, and emulsification performance to ensure consistent quality.