Polyglyceryl-4 caprate
[CAS 160391-93-5]

Identification

• Classification: Organic raw materials >> Carboxylic compounds and derivatives >> Carboxylic esters and their derivatives
• Name: Polyglyceryl-4 caprate
• CAS Registry Number: 160391-93-5
• EC Number: 640-993-3

Safety Data

• Hazard Symbols: GHS05 Warning
• Risk Statements: H302-H315-H319-H335
• Safety Statements: P280-P305+P351+P338

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319

chemBlink Chemical Story

A molecule does not need an ionic charge to behave like a surfactant. Polyglyceryl-4 caprate, CAS 160391-93-5, uses a different strategy: several glycerol units provide a highly polar, hydrogen-bonding head group, while a capric-acid-derived C10 chain supplies the hydrophobic tail. The result is a nonionic polyglycerol fatty acid ester used mainly in emulsifying and cleansing formulations.

The name again describes an average family rather than one perfectly monodisperse compound. Polyglycerol is produced by linking glycerol units, creating a distribution of oligomers. Esterification with capric acid then yields products with related degrees of polymerization and esterification. Regulatory and ingredient databases therefore treat polyglyceryl-4 caprate as a polymeric or oligomeric substance, not as one small molecule whose exact formula captures every commercial sample.

Its surface chemistry is nevertheless easy to visualize. The caprate chain prefers oil; the polyglycerol portion forms many hydrogen bonds with water. At an oil-water interface, those two preferences pull in opposite directions and anchor the molecule at the boundary. This can lower interfacial tension, stabilize droplets, solubilize oily ingredients, and help water-based cleansers pick up hydrophobic material.

Polyglycerol fatty acid esters have become important because their hydrophilic-lipophilic balance can be tuned by both the polyglycerol chain length and the fatty-acid component. Reviews describe a remarkably broad design space: different members can stabilize oil-in-water or water-in-oil emulsions, form self-assembled structures, modify fat crystallization, solubilize flavors, and function in cosmetic and pharmaceutical systems. Polyglyceryl-4 caprate occupies the shorter-head, medium-chain region of that family, giving it useful balance between water compatibility and oil affinity.

There is also a sustainability-related reason formulators pay attention to polyglycerol esters. They provide nonionic surfactant functionality without requiring a polyethylene glycol chain. That does not automatically make every formulation "green," but it creates another molecular toolkit based on glycerol and fatty acids, both of which can be sourced from renewable feedstocks. Modern reviews discuss PGFEs as potential alternatives to PEG-based nonionic surfactants in some applications.

The memorable idea is that emulsification can be designed with a modular head and tail. Glycerol units determine how strongly the molecule interacts with water; the C10 fatty chain determines how strongly it interacts with oil. Change either side and the balance moves. Polyglyceryl-4 caprate is therefore less a single magic emulsifier than one coordinate in a large map of tunable amphiphiles.

References:
1. FDA Global Substance Registration System, Polyglyceryl-4 Caprate, CAS 160391-93-5.
2. Recent Advances in the Properties and Applications of Polyglycerol Fatty Acid Esters. Polymers. 2025, 17, 879.
3. Higuchi T. Emulsification and solubilization characteristics of polyglycerol fatty acid esters. Oleoscience. 2019, 19, 405-410.
4. Cosmetic ingredient databases and regulatory records for Polyglyceryl-4 Caprate.

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