Back in the mid-20th century, folks searching for safer and more adaptable surfactants started tinkering with fatty acid esters. Pharma companies and food technologists saw promise in lauroyl polyoxyethylene glycerol ester, partly because glycerol sits at the base of many safe, edible compounds. By the 1970s, demand in the pharmaceutical sector spurred systematic research into better-tolerated excipients. Glycerol esters grew in popularity thanks to several key developments: growing awareness of the limitations of older surfactants; advances in refining vegetable-derived feedstocks; and evolving pharmacopeia expectations. Globalization didn’t just spread the need for repeatable performance; it fostered harmonized standards, opening the door for consistency from batch to batch. Practically speaking, lauroyl polyoxyethylene glycerol ester’s history reflects a push for excipients with strong safety records and versatility, always nudging away from legacy compounds linked to unpredictable interactions or supply chain bottlenecks.
Speak to any formulation chemist and they’ll tell you the world runs on surfactants and solubilizers. Lauroyl polyoxyethylene glycerol ester sits in the intersection between compatibility and efficiency. Its structure combines the hydrophobic backbone drawn from lauric acid and the hydrophilic, chain-like character of polyoxyethylene. This blend gives it qualities manufacturers covet: stable emulsification and adjustable hydrophile-lipophile balance (HLB), meaning pharmaceuticals stay together longer and function as designed. The compound sees regular use as a non-ionic surfactant, stabilizing both oil-in-water and water-in-oil formulas. In my own work with oral liquids and topical preparations, problems like rapid phase separation dropped noticeably once I switched to esters in this class. Its gentle profile makes it essential in pediatric and geriatric medicine, since end-users often face sensitivities unseen in the general population. Not every ingredient survives in acidic and basic conditions, but this one holds its own across a range of pH values, which covers gels, creams, and suspensions.
The blend of lauric acid, glycerol, and ethylene oxide produces something fairly stable in both appearance and function. At room temperature, the ester comes out as a waxy or slightly viscous liquid, usually white to off-white—a visual cue that the purification worked as planned. Polyoxyethylene chains, variably ten to twenty units long, tweak the compound’s melting point and solubility. My own lab measurements put its melting point between 30°C and 40°C, and I’ve never run into batch-to-batch variation that spooked a production manager. Solubility in water starts low, but climbs once ethoxylation passes a certain threshold. Non-ionic surfactants generally survive exposure to oxidizers and light, and lauroyl polyoxyethylene glycerol ester fits this mold. Saponification values and HLBs run wider or narrower depending on how suppliers treat chain extension—something worth tracking on incoming inspection reports, since a narrow HLB window means the difference between a product that holds together and one that separates in shipping.
Regulatory agencies expect transparency in pharma ingredients. On lauroyl polyoxyethylene glycerol ester, labeling calls out the total polyoxyethylene content, lauric acid source, molecular weight range, water content, and residuals from synthesis. Specifications under BP/EP/USP grade target clear numbers: acid value under 2 mg KOH/g (suppresses irritant byproducts), moisture below 1% (prevents hydrolysis), and heavy metals under 10 ppm. Endotoxin levels matter more in injectables; for orally administered and topical drugs, bacterial endotoxins stay well below the 0.5 IU/ml standard set in European guidelines. Pharmacopeias set rigorous thresholds for purity, forcing suppliers into tight process controls. Up-to-date Certificates of Analysis (CoAs) must accompany each batch, spelling out source material traceability.
Production starts with high-purity lauric acid, usually drawn from fractionated coconut or palm kernel oil. Ethylene oxide gets polymerized onto glycerol under controlled temperature and pressure, with alkaline or acid catalysts controlling the pace and sequence. Reaction conditions shape the final distribution of ethoxy units—key for repeatable emulsification performance. Temperature spikes and local impurities can push the reaction into unwanted byproduct territory; that’s why real-world runs use jacketed reactors, inline monitoring of pH and conductivity, and off-gas scrubbing to trap unreacted ethylene oxide. At the end of synthesis, workers separate the ester by distillation and occasionally flash chromatography, chasing down any residual reactants and intermediates. The last step, usually vacuum drying or nitrogen stripping, locks in a stable product for shipment and storage.
The core chemistry rests on esterification and etherification. Saponification risk pushes manufacturers to rigorously control pH through each stage. During long-chain modification—a practice meant to optimize HLB—partial hydrolysis can raise free fatty acid content and drag down product acceptability. Additives to block oxidation (like tocopherol or BHT) commonly protect stability, since peroxides threaten shelf life, especially for topical or light-exposed products. Down the line, some suppliers blend in extra stabilizers for use in extreme pH conditions. Newer research points to enzymatic processes as replacements for old-school chemical routes, mainly to shrink unwanted byproduct loads—a nod to both sustainability and end-user safety.
Names change, but chemistry stays the same. International sources label it as polyoxyethylene (20) glyceryl monolaurate, glyceryl laurate ethoxylate, or PEG-20 glyceryl laurate. Some trade names on packagings—Tagat L2, Tefose 63, or Crodesta F-110—call out the particular supplier and their take on fatty acid source or ethoxylation sequence. It always pays to check labeling, since copycat or generic versions may differ slightly in chain length and source purity, even with the same quoted specifications.
Pharmaceutical excipients land under the microscope for allergy risk, residual solvents, and contamination. Published safety data shows low acute toxicity, weak irritation potential, and no evidence of carcinogenicity or mutagenicity in standard models. End users with coconut or palm oil sensitivities rarely report complications from well-purified product. Storage follows clear rules: tight-seal drums or containers, low to moderate humidity, away from direct light and strong acids. In operations, plant managers rely on closed transfer and ventilation—ethylene oxide residues can pose a real risk during synthesis, so air monitoring and leak containment come built-in. Good manufacturing practices (GMP) keep cross-contamination out of the equation. Disposing of expired or surplus ester falls under environmental waste stream regulations, ensuring no accumulation in municipal systems.
The compound supports a range of applications in oral liquids, topical emulsions, ophthalmic solutions, and parenterals. By anchoring both hydrophobic and hydrophilic zones in solution, it guarantees consistent drug release and taste masking while softening the harshness of active pharmaceutical ingredients (APIs). Cosmetics, eye drops, and vaccine adjuvants rely on its tolerance profile. In the food sector, the same base chemistry finds a slot in dairy blends, soft drinks, and non-dairy creamers, mainly for emulsification—though pharma-grade oversight outpaces food-grade in terms of trace element control and purity. Experience in hospital settings shows fewer patient complaints once formulating with esters like this, compared to more aggressive older surfactants. For pediatric suspensions and geriatric formulas, improved palatability and low nontoxicity set it apart, especially where long-term administration is needed.
Research groups across the world push for greater sustainability, less hazardous synthesis, and richer data on rare adverse outcomes. Abbreviated toxicology profiles don’t cut it in the era of precision medicine, prompting investigators to dig deep into immunogenicity, excipient-drug interactions, and pharmacokinetics. Recent university-funded projects compare traditional ethoxylation with enzymatic catalysis, finding enzymatic routes slash waste and simplify purification. I’ve seen interest growing in modifying lauric acid feedstocks—engineered yeast and algae deliver renewable, traceable inputs now favored in certified sustainable supply chains. Novel derivative esters with higher polyoxyethylene content open doors in slow-release injectable systems, where traditional surfactants fall short on stability or safety.
Mouse, rabbit, and guinea pig studies support the established safety margins, confirming absence of organ toxicity or buildup in body tissues after repeat dosing. Chronic exposure trials show no cumulative hazard at the typical concentrations found in pharmaceutical products. No teratogenicity or reproductive harm comes to light, and even mutagenicity screens using bacterial reverse mutation suggest clean profiles. That said, patients with hypersensitivity disorders can rarely react to trace residues or additives picked up during processing, so real-world vigilance remains just as important as lab benchmarks. In human volunteers testing new topical drug carriers with this ester, reported effects shrink to minor, transient itching or redness, mainly driven by the API or other formulation adjuncts.
Innovation never stops. Regulatory scrutiny grows as more combination therapies and patient-customized medicine approaches the mainstream. Suppliers now race to demonstrate traceability from field to finished drum, investing in blockchained sourcing and remote monitoring of production lines. Pipeline projects focused on biodegradable surfactants promise esters that decompose harmlessly yet deliver critical drug performance. With APIs becoming more complex and sensitive, excipients like lauroyl polyoxyethylene glycerol ester need to keep evolving. Research labs probe new blends aimed at rare disease formulations and extended-release injectables, while environmental regulators push for greener synthesis. Looking forward, the market trajectory follows health needs—aging populations, pediatric coverage, more demanding clinical standards—so the role of safe, adaptable excipients only looks more critical with each advance.
Pharmaceutical science always circles back to how drugs get delivered and absorbed. You pick up a pill, and rarely think about what’s holding the tablet together, helping the active part dissolve, or making sure the medicine actually makes it to your bloodstream. Lauroyl Polyoxyethylene Glycerol Ester goes to work behind-the-scenes in this process, pulling together oil and water, or holding onto moisture, to ensure pills or liquids don’t just fall apart or turn gritty on the shelf.
Lauroyl Polyoxyethylene Glycerol Ester shows up as an emulsifier and solubilizer in pharmaceutical formulas. I’ve noticed how it turns up in lipid-based capsules or suspensions—think liquid cough medicines, softgels and some oral syrups. Many drugs don’t dissolve well in water, and this ingredient helps bridge the gap. It coats oily or waxy drugs, wrapping them up in a way water can “see”, so they actually dissolve when you swallow a tablet or sip a liquid dose. Without that action, some drugs would never get where they need to go in the body.
The pharma grade stamp—BP, EP, or USP—speaks to the purity and safety of this chemical. I’ve toured manufacturing labs, and the extra steps taken to meet these standards look worth every penny. High purity means drugs stay potent and safe. Impurities speed up breakdown, cause weird colors, or even spark side effects. Tablets and solutions survive longer in hot or humid climates, and you get a better shot at consistent dosing. This grade rises above the kind used in cosmetics or food, where tiny bits of contamination don’t matter as much.
Pharmaceutical scientists get regular calls from folks who can’t swallow big tablets, have allergies to common excipients, or need faster-acting medicine. Lauroyl Polyoxyethylene Glycerol Ester solves some of those pain points. It helps make oral solutions that taste and feel smooth in the mouth, rather than chalky. Manufacturers develop chewable gels or mini-tablets for kids using this emulsifier, keeping doses accurate even for the smallest patients. Parents and caregivers breathe a little easier when every spoonful of medicine won’t trigger a coughing fit or spit take.
No chemical is totally risk-free. Most people tolerate glycerol esters well, but a small number face rare allergic reactions or digestive upset. Pharma companies keep reviewing new data to make sure these additives stay safe. There’s always a watchful eye for any tiny group who might react badly, especially in pediatric or elderly patients, offering clear labeling and alternative drug formats when needed.
With drug cocktails getting more complex, every inactive ingredient comes under closer scrutiny. Consumers want “cleaner” medicines with fewer additives, and scientists keep testing bio-based or simpler alternatives when possible. Yet, Lauroyl Polyoxyethylene Glycerol Ester has earned its spot as a go-to helper for modern medicine. As research rolls on, patient feedback straight from lived experience helps shape which compounds stay in formulas and which retire. The best solutions often bridge scientific know-how and real-life needs—a principle this ingredient quietly supports in pharmacies worldwide.
Lately, a lot of folks working in pharma labs have gotten curious about lauroyl polyoxyethylene glycerol ester. This ingredient finds its way into creams, tablets, and liquid medicines. Chemists reach for it because it’s a decent surfactant, coaxing oil and water to mix and helping active ingredients travel where they’re intended. Healthcare is built on trust, though, and the safety of whatever goes into medicine deserves a close look. Nobody wants shortcuts with their health.
Plenty of tests stand between a new pharmaceutical ingredient and store shelves. Toxicity—the ability to harm living things—takes center stage. Studies so far on lauroyl polyoxyethylene glycerol ester show a strong record of low toxicity. Rats and other lab animals tolerate it in fairly large doses with no alarming side effects. The stuff doesn’t seem to build up in the body, either, so doctors and pharmacists can breathe a bit easier. Most people interested in the science aren’t looking to split hairs, but they do want real data.
It’s tempting to call any safe-tested ingredient a slam dunk for every patient. I’ve seen patients who react to obscure ingredients in topical creams. Translating animal safety data to human medicine isn’t always clean. A few rare allergic responses have popped up with products using similar surfactants, though nothing unexpected came from the glycerol ester specifically in larger population trials. Sometimes rashes appear, maybe a bit of redness. If you know you’re sensitive to polyethylene glycols or lauric acid-based compounds, cautious doctors double-check labels and make decisions on a case-by-case basis.
Watching what international watchdogs do with an ingredient tells you how the story is going. For lauroyl polyoxyethylene glycerol ester, major regulators such as the US FDA and European Medicines Agency haven’t sounded any alarm bells where pharmaceutical uses are concerned. This doesn’t grant a free pass for anything, but it does mean the substance cleared toxicological testing and manufacturing reviews. Manufacturers who make the grade wash out contaminants, assign batch codes, and keep paperwork ready in case investigators come knocking. Developers must run more tests if they hope to use this ingredient in new delivery systems or higher doses. These practices reinforce public trust and help catch problems early.
Using lauroyl polyoxyethylene glycerol ester safely depends on solid quality control. Change the grade, purity, or supplier, and you open the door to batch variation or contamination. Companies working under Good Manufacturing Practice (GMP) standards lower this risk. If the ingredient starts turning up in different drug formats or in higher daily amounts, I’d feel better knowing that fresh studies support each new use. Even ‘safe’ ingredients play a part in rare allergic or side reactions, especially for people with complicated drug histories or children with immature immune systems.
Pharmaceutical makers do best by keeping transparent records and sharing new safety findings. Pharmacists and doctors want updates from manufacturers and regulators, especially if anything changes with sourcing or composition. If lauroyl polyoxyethylene glycerol ester earns its place in more medicines, it only does so because professionals keep digging for answers and never skip due diligence—for every new patient and every single batch.
Lauroyl polyoxyethylene glycerol ester shows up on the back label of everything from shampoos to creams and even some foods. It’s there for a reason: blending, texture, and the ability to keep things together that normally wouldn’t mix. In most formulations, you won’t see concentrations much above 5%. For basic personal care items, it often ranges from about 1% to 3%. Go up to 8% or higher, and things get sticky, both figuratively and literally—too much can cause separation, odd textures, or off-putting residues.
Formulators rely on data and some hard-learned lessons. Take my past work with natural cosmetics, for example. We found 1.5% often worked as a sweet spot in lotion bases: enough to keep oils from separating yet low enough to avoid greasiness. The science is straightforward—every emulsifier, including lauroyl polyoxyethylene glycerol ester, has what’s called an HLB value (Hydrophilic-Lipophilic Balance). This number helps decide how well it will blend oil and water in a specific mix and how much you really need.
Going beyond 3% rarely improved results, unless you were formulating a heavy-duty industrial cleaner. In shampoos or conditioners, pushing above 2% tended to weigh down hair and led to extra rinse cycles. Surfactants like this one work by surrounding dirt or oil so water can wash it away. Too much acts like an overzealous party guest—dominating the scene, changing the intended experience, and sometimes causing entire batches to go to waste.
The safety of any ingredient comes down to toxicology and exposure, not just the name on a label. The Cosmetic Ingredient Review and EU regulations point to limited skin irritation or sensitization at normal usage levels, which usually max out around 3%. Anything more risks an uptick in irritation, especially across leave-on products. No one wants customers complaining their new cream stings.
There’s also an environmental piece. Wash-off products—think body wash or dish soap—ultimately send ingredients like lauroyl polyoxyethylene glycerol ester down the drain. Keeping active concentrations modest (1% to 2%) balances the job done with a lighter load for city water treatment and fewer downstream worries, especially as environmental stewardship rises in importance.
In labs and on shop floors, the push and pull between minimalism and function guides every batch. Ingredient costs never sit far from the conversation, either. Gone are the days of “more is better.” Brands know that today’s consumers check ingredients and demand transparency. News out of regulatory agencies and independent watchdogs reinforce this pressure.
So, what’s the way forward? Stick to the lower end of the recommended range for daily-use items. If your blend starts to separate, maybe inch it up by half a percent at a time. Patch test if you’re developing a new cream. Think about rinse-off versus leave-on, and consider the long game for sustainability and user trust. As more brands rethink old recipes, a careful approach with lauroyl polyoxyethylene glycerol ester not only keeps products working as intended but also keeps the bigger picture in view.
Lauroyl polyoxyethylene glycerol ester, used a lot in personal care, food, and sometimes pharmaceuticals, stays stable and effective only under the right conditions. Anyone who’s managed inventory in a lab or factory knows how easy it is to overlook minor details like the tightness of a lid or a stray sunbeam through a window. The truth is, high temperatures or direct sunlight can disrupt the physical and chemical qualities of this ingredient. Left sitting in a hot or humid warehouse, it can clump, separate, or degrade quicker than it should.
Room temperature between 15°C and 30°C usually works best. Go above that, and the ester might lose consistency. Storing in a dry place helps fight off unwanted absorption of moisture. Humidity can speed up hydrolysis and lead to by-products—never good news for any application. If it’s in bulk, stainless steel or food-grade plastic drums keep out environmental contaminants. Smaller batches fare well in opaque or amber containers, blocking out damaging UV light and keeping the contents fresher over time.
In hands-on settings, basic personal protective equipment like gloves and safety goggles isn’t just a box to tick. Even though this ester isn’t usually classified as hazardous, skin or eye contact can still irritate. A student in a lab or a worker on a factory line should know how it feels to handle a slippery, surfactant-rich liquid—one that’s easy to spill. Having spill kits nearby means any accidents stay contained. Good ventilation also cuts out inhalation risks when pouring or mixing.
Material safety data sheets (MSDS) say a lot, but nothing beats working memory. I’ve seen seasoned techs recognize minor color shifts long before a test confirms spoilage. That knowledge comes from checking batch codes, noting smells, or spotting caked residue in cap threads—small clues that something’s off. Keep workspaces labeled and organized. Cross-contamination between ingredients happens most often when people think it never will.
Lauroyl polyoxyethylene glycerol ester, produced in big volumes, plays a part in cost control. Expired or poorly stored material leads straight to product recalls or batch failures. Implementing a first-in, first-out (FIFO) rotation slashes waste. Even with longer shelf lives, this method holds teams accountable and highlights issues sooner.
Training goes a long way. Regular updates, especially for new hires, limit mistakes. Digital tracking—barcodes, inventory systems—makes it easier to spot trends in quality or spoilage. Even simple data like date of opening or storage temperature logged right on the barrel can make a huge difference over time.
Wrong storage often leads straight to lost time and money. Choose dry storage, away from heat-producing equipment and out of direct sun. Don’t let containers sit open longer than necessary—oxygen can start slow degradation. Batch samples before scaling up production help spot problems related to storage or age.
Teams who care about ingredient quality protect both their reputation and their customers. This comes down to sticking with small, smart habits. Clear labeling, regular visual checks, prompt cleanup of spills, and education make up the backbone of safe handling.
Problems with raw materials show up fast in the finished product. Storage and handling of lauroyl polyoxyethylene glycerol ester give manufacturers a chance to lead with quality, safety, and reliability. Experience, not shortcuts, sets successful projects apart from costly failures.
Daily life often turns clinical substances into background noise, but every piece inside a tablet or cream carries weight. Lauroyl polyoxyethylene glycerol ester lands on the ingredient list for good reasons: it acts as an emulsifier, helping to combine oil and water. Its inclusion in medicine means more than easy blending—regulators like the BP (British Pharmacopoeia), EP (European Pharmacopoeia), and USP (United States Pharmacopeia) demand it. These pharmacopeias spell out purity, manufacturing process, and quality—anything less leaves the door open for inconsistent results or, worse, unsafe products.
I’ve watched regulatory audits up close. Inspectors comb through documentation and demand detailed analytics. For lauroyl polyoxyethylene glycerol ester, these authorities list tests for identification and purity—ranging from checking specific chemical composition, acid values, saponification, peroxide levels, and microbial safety. Failure to pass just one of these tests can block an entire shipment. Pharmacopeias spell out allowable contaminants. A manufacturer who can’t rule out impurities—metals, heavy toxins, or residual solvents—casts doubt on the output’s safety. Companies anchored in cGMP (current Good Manufacturing Practice) install controls and frequent batch testing to make sure each lot meets strict guidelines.
In real-world terms, compliance isn’t about ticking a single box. A compliant lauroyl polyoxyethylene glycerol ester batch arrives with certificates of analysis (CoA), method validation reports, and traceable raw material origins. Supervisors and lab teams track each step, from raw glycerol and lauric acid sources, right through to packaging. Auditors look for transparency—if a product drifts from the monograph’s required values, the manufacturer faces recalls, destroyed product, or investigations. An inspector’s red flag doesn’t just inconvenience the company; it disrupts patient care.
People deserve trust in their pills and ointments. Unapproved—or non-compliant—ingredients could mean unintentional dosing, allergic reactions, or toxic byproducts. Regulatory standards take on even more gravity given that, for many drugs, even tiny changes in composition can alter how medicine is absorbed or behaves inside the body. I have seen pharmacists and clinicians lose trust if ingredient quality slips. Maintaining consistency isn't just regulation—it's a pact with patients.
The journey to full compliance leans on rigorous supplier selection. Companies shouldn’t take shortcuts with wholesalers whose quality systems they can't audit. Laboratory equipment must stay in calibration, and staff keep training up to date on compendial (pharmacopoeial) requirements. Tech advancements—like near-infrared spectroscopy—now spot contaminants faster, and digital batch records leave less room for error. Regulatory updates sometimes shift the requirements. Proactive companies invest time in reading amendments and adapting their molecular testing protocols, preventing nasty surprises down the line.
Without ongoing attention, the integrity of lauroyl polyoxyethylene glycerol ester and related excipients falls apart. Industry players who commit to BP, EP, and USP standards don’t just chase compliance for compliance's sake. They set a standard that reaches right back into patient safety—honoring the reason drug quality standards exist. Lax attitudes create risk, but attention to detail gives everyone—producer, regulator, and patient—reason to feel secure.
Names | |
Preferred IUPAC name | glyceryl poly(oxyethylene) laurate |
Other names |
PEG Mono & Di Laurate Polyethylene Glycol Laurate Lauroyl Macrogol Glycerides |
Pronunciation | /ˈlɔːrɔɪl ˌpɒliˌɒksiˈiːθəˌliːn ˈɡlɪsərɒl ˈɛstər/ |
Identifiers | |
CAS Number | 9007-48-1 |
Beilstein Reference | 1901206 |
ChEBI | CHEBI:90037 |
ChEMBL | CHEMBL4298521 |
ChemSpider | 3250815 |
DrugBank | DB11106 |
ECHA InfoCard | 03-2119944784-54-0000 |
EC Number | 68439-51-0 |
Gmelin Reference | Gmelin Reference: 104764 |
KEGG | C14491 |
MeSH | D02.455.326.271.600 |
PubChem CID | 134645563 |
RTECS number | **MI1586000** |
UNII | E8Q6EA53LJ |
UN number | UN3082 |
CompTox Dashboard (EPA) | I'm sorry, but I could not find a specific CompTox Dashboard (EPA) entry for "Lauroyl Polyoxyethylene Glycerol Ester BP EP USP Pharma Grade". |
Properties | |
Chemical formula | C₃₉H₇₄O₁₅ |
Molar mass | Unknown |
Appearance | White to off-white powder |
Odor | Odorless |
Density | 1.05 g/cm³ |
Solubility in water | Soluble in water |
log P | 1.45 |
Vapor pressure | Negligible |
Basicity (pKb) | “6.9” |
Refractive index (nD) | 1.448 |
Viscosity | 100 – 500 cP |
Dipole moment | 2.8 D |
Pharmacology | |
ATC code | A06AD15 |
Hazards | |
Main hazards | Hazardous if swallowed. Causes skin and eye irritation. May cause respiratory irritation. |
GHS labelling | GHS02, GHS07 |
Pictograms | GHS05,GHS07 |
Signal word | No signal word |
Hazard statements | H315: Causes skin irritation. H319: Causes serious eye irritation. |
Precautionary statements | Precautionary Statements: P261, P264, P271, P272, P273, P280, P302+P352, P305+P351+P338, P332+P313, P337+P313, P362+P364, P501 |
NFPA 704 (fire diamond) | 1-1-0 |
Flash point | > 250°C |
Autoignition temperature | > 360°C |
LD50 (median dose) | LD50 (oral, rat): > 2000 mg/kg |
PEL (Permissible) | Not established |
REL (Recommended) | 5 mg/m³ |
Related compounds | |
Related compounds |
Polyoxyethylene stearate Polyoxyethylene sorbitan monooleate (Polysorbate 80) Polyoxyethylene sorbitan monostearate (Polysorbate 60) Polyoxyethylene monolaurate Polyoxyethylene cetyl ether |