Span 60
[CAS# 1338-41-6]

Identification

• Classification: Surfactant >> Nonionic surfactant >> Polyol ester type
• Name: Span 60
• Synonyms: Sorbitan monooctadecanoate; Sorbitan stearate
• Molecular Formula: C₂₄H₄₆O₆
• Molecular Weight: 430.62
• CAS Registry Number: 1338-41-6
• EC Number: 215-664-9
• FEMA: 3028
• SMILES: CCCCCCCCCCCCCCCCCC(=O)OC[C@H]([C@@H]1[C@@H]([C@H](CO1)O)O)O

Properties

• Density: 1.1±0.1 g/cm³, Calc.^*
• Melting point: 54-57 °C (Expl.)
• Index of Refraction: 1.497, Calc.^*
• Boiling Point: 579.0±45.0 °C (760 mmHg), Calc.^*
• Flash Point: 185.3±22.2 °C, Calc.^*, 150 °C (Expl.)

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H412-H315
• Safety Statements: P273

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412

Discovery and Applications

Span 60, also known as Sorbitan monostearate, is a nonionic surfactant derived from the esterification of sorbitol and stearic acid. It appears as an off-white to yellowish solid with a waxy texture and is widely used in various industrial applications due to its emulsifying, stabilizing, and dispersing properties. The compound belongs to the sorbitan ester family, which includes surfactants with different fatty acid chains, each exhibiting distinct functionalities in formulation chemistry.

The development of sorbitan esters, including Span 60, can be traced back to early research in emulsification technology, where scientists explored the role of nonionic surfactants in stabilizing oil-in-water and water-in-oil emulsions. As industrial and commercial needs expanded, Span 60 was identified as a valuable emulsifier due to its hydrophilic-lipophilic balance (HLB) value of approximately 4.7, making it particularly suitable for water-in-oil emulsions. Its discovery and characterization have been well documented in surfactant chemistry literature, leading to its widespread adoption in various industries.

Span 60 is extensively used in the food industry as an emulsifier, where it helps maintain the stability and texture of products such as margarine, creams, and baked goods. It prevents phase separation in emulsified food formulations and enhances the consistency of fat-containing products. Due to its nonionic nature, it is compatible with other emulsifiers, allowing for synergistic effects in complex formulations. Regulatory authorities have evaluated its safety, permitting its use within specified limits in food applications.

In the pharmaceutical industry, Span 60 plays a crucial role as an excipient in drug formulations. It is commonly used in topical creams, lotions, and ointments, where it aids in emulsification and enhances the stability of active pharmaceutical ingredients. It also contributes to controlled drug release by modifying the solubility and dispersion of certain drug compounds. In some cases, it is employed in liposomal drug delivery systems, where its amphiphilic nature facilitates the formation of stable vesicles.

The cosmetic and personal care industry also benefits from Span 60's emulsifying and stabilizing properties. It is frequently incorporated into creams, lotions, and other skincare products to improve texture and consistency. In combination with other surfactants, it helps create smooth, homogeneous formulations that enhance product performance. Its ability to form stable emulsions ensures that active ingredients are evenly distributed, improving the overall efficacy of cosmetic products.

In industrial applications, Span 60 is utilized in the production of lubricants, coatings, and textile processing agents. It serves as a dispersing agent in pigment formulations, aiding in the uniform distribution of colorants in paints and coatings. Additionally, it is used in agricultural formulations to improve the dispersion and stability of pesticide and herbicide mixtures. Its compatibility with both hydrophilic and lipophilic components makes it a versatile additive in various manufacturing processes.

Span 60's safety and regulatory status have been extensively studied, with evaluations indicating its low toxicity and biodegradability. It is generally recognized as safe for use in food, pharmaceuticals, and cosmetics, provided it is used within recommended concentrations. Studies on its environmental impact suggest that it undergoes degradation under standard conditions, minimizing long-term ecological concerns.

Overall, Span 60 is a well-established nonionic surfactant with broad applications in multiple industries. Its emulsifying, stabilizing, and dispersing properties make it an essential component in food, pharmaceuticals, cosmetics, and industrial formulations. Its continued use is supported by extensive research and regulatory approvals, ensuring its role as a reliable and effective ingredient in diverse applications.

References

2021. Metformin hydrochloride entrapment in sorbitan monostearate for intestinal permeability enhancement and pharmacodynamics. Scientific Reports, 11(1).
DOI: 10.1038/s41598-021-99649-3

2024. Unveiling the formation capacity of multicomponent oleogels: Performance of lecithin interacting with monostearate derivatives. Food research international (Ottawa, Ont.), 189.
DOI: 10.1016/j.foodres.2024.114430

2023. The effect of polyethylene glycol sorbitan monostearate on the morphological characteristics and performance of thermoplastic starch/biodegradable polyester blend films. International Journal of Biological Macromolecules, 233.
DOI: 10.1016/j.ijbiomac.2023.123332