Buyers most often ask which PEG-40 hydrogenated castor oil grades are appropriate for pharmaceutical versus cosmetic or industrial formulation: pharmaceutical work generally calls for USP-NF or Ph. Eur. compliant material (commonly marketed under names such as Cremophor RH 40, with catalog references like COH 40 denoting the same PEG-40 hydrogenated castor oil chemistry), while cosmetic and technical formulations can use a cosmetic-grade or technical-grade version with looser hydroxyl-value and color tolerances. The three grades differ mainly in purity control, water content, and documentation, not in the base chemistry.
What PEG-40 Hydrogenated Castor Oil Is
PEG-40 hydrogenated castor oil (CAS 61788-85-0) is a nonionic surfactant produced by reacting hydrogenated castor oil with ethylene oxide (approximately 40 moles). The result is an amphiphilic molecule with an HLB value typically in the 14-16 range, making it an effective oil-in-water emulsifier and a solubilizer for lipophilic actives — fat-soluble vitamins, essential oils, flavor and fragrance oils, and poorly water-soluble drug substances — in aqueous or hydro-alcoholic systems. It is chemically related to, but distinct from, the non-hydrogenated PEG-35 castor oil (Cremophor EL type) used in different applications.
Grades and Standards
Not every supplier grade carries a pharmacopeial monograph, so buyers should confirm which standard, if any, applies before specifying a grade for a given use.
| Grade | Reference standard | Typical appearance | Common use |
|---|---|---|---|
| Pharma / NF grade | USP-NF monograph: Polyoxyl 40 Hydrogenated Castor Oil | Pale yellow waxy solid to soft paste | Oral liquids, topical and parenteral-adjacent formulation aids where a compendial excipient is required |
| Ph. Eur. grade | Macrogolglycerol Hydroxystearate monograph | Pale yellow paste | EU-registered pharmaceutical and dermatological products |
| Cosmetic / technical grade | Supplier specification (no compendial monograph required) | Yellow to amber paste or flakes | Creams, lotions, hair care solubilizers, industrial cleaning and degreasing formulations |
Physical Form, Packaging & Handling
At room temperature the material is typically a waxy solid or soft paste with a melting range around 26-30°C, meaning it can appear semi-liquid in warm climates and firm up in cooler storage. It is commonly supplied in fiber or steel drums (often in the 25 kg to 190 kg range) rather than bags, reflecting its paste-like consistency; larger-volume users may source in heated IBCs for pumpable handling. Gentle warming (typically below 50°C) is standard practice to liquefy the material for dosing without degrading the ethoxylate chain.
Formulation Notes: Solubility, HLB & Stability
PEG-40 hydrogenated castor oil is soluble in water, ethanol, and most polar organic solvents, forming clear to slightly hazy micellar solutions at use concentrations — a property widely exploited to solubilize oil-soluble actives in aqueous vehicles. It is stable across a broad pH range under normal storage and processing conditions, but like other PEG-ester surfactants it can undergo slow hydrolysis under prolonged exposure to strong acid or alkaline conditions combined with heat, and it is susceptible to oxidative degradation over long-term storage, which is why many commercial batches include a small antioxidant addition. Compatibility testing with the specific active and other excipients in a formulation is standard practice before scale-up.
Applications by Industry
In pharmaceutical manufacturing, the material functions as a solubilizer and emulsification aid in oral and topical dosage forms. In cosmetics and personal care, it is used as an emulsifier and solubilizer in creams, lotions, hair conditioners, and clear or translucent aqueous formulations containing oils or fragrance. In industrial and household formulation, its surfactant properties support degreasing and cleaning blends. Across all three, the underlying function is the same — bridging oil and water phases — with grade selection driven by the regulatory category of the finished product.
QA Documentation to Request
Regardless of grade, buyers should request a current Certificate of Analysis showing appearance, hydroxyl value, saponification value, water content (Karl Fischer), and pH of an aqueous solution; a full specification sheet referencing the applicable pharmacopeial monograph where one is claimed; and lot-level traceability documentation. For pharmaceutical and sensitive cosmetic applications, confirmation of dedicated or validated-clean manufacturing lines and stability data relevant to the intended shelf life are commonly requested as part of supplier qualification.
FAQ
What is the difference between Cremophor RH 40 and Cremophor EL?
Cremophor RH 40 (PEG-40 hydrogenated castor oil) is made from hydrogenated castor oil and is typically a waxy solid, while Cremophor EL (PEG-35 castor oil) uses non-hydrogenated castor oil and is a liquid at room temperature; they are used for similar solubilizing functions but are not interchangeable without reformulation testing.
Which PEG-40 hydrogenated castor oil grade is used in pharmaceutical formulation?
Formulators generally specify material meeting the USP-NF monograph for Polyoxyl 40 Hydrogenated Castor Oil or, for EU-registered products, the Ph. Eur. Macrogolglycerol Hydroxystearate monograph, rather than a technical or cosmetic-grade material.
How should PEG-40 hydrogenated castor oil be stored?
It should be stored in tightly closed original containers in a cool, dry area away from direct heat and strong oxidizers; gentle warming is used only at the point of dosing to liquefy the material for processing.
How DIC supports this
DIC stocks PEG-40 hydrogenated castor oil regionally across pharma-grade and technical-grade options, with documentation packages aligned to the standard the buyer's application requires. Sensitive pharmaceutical-grade lots are handled through dedicated, controlled-condition warehousing, and vendor-managed inventory arrangements are available for formulators running continuous production schedules.
