Name: Cetyl Alcohol
CAS No: Hexadecan-1-ol [36653-82-4]
BP: Cetyl Alcohol JP: Cetanol PhEur: Cetyl Alcohol USP-NF: Cetyl Alcohol
Alcohol cetylicus; Avol; Cachalot; Crodacol C70; Crodacol C90; Crodacol C95; ethal; ethol; HallStar CO-1695; 1-hexadecanol; nhexadecyl alcohol; Hyfatol 16-95; Hyfatol 16-98; Kessco CA; Lanette 16; Lipocol C; Nacol 16-95; palmityl alcohol; Rita CA; Speziol C16 Pharma; Tego Alkanol 16; Vegarol 1695.
Hexadecan-1-ol [36653-82-4]
C16H34O 242.44 (for pure material) Cetyl alcohol, used in pharmaceutical preparations, is a mixture of solid aliphatic alcohols comprising mainly 1-hexadecanol (C16H34O). The USP32–NF27 specifies not less than 90.0% of cetyl alcohol, the remainder consisting chiefly of related alcohols. Commercially, many grades of cetyl alcohol are available as mixtures of cetyl alcohol (60–70%) and stearyl alcohol (20–30%), the remainder being related alcohols.
Cetyl alcohol is widely used in cosmetics and pharmaceutical formulations such as suppositories, modified-release solid dosage forms, emulsions, lotions, creams, and ointments. In suppositories cetyl alcohol is used to raise the melting point of the base, and in modified-release dosage forms it may be used to form a permeable barrier coating. In lotions, creams, and ointments cetyl alcohol is used because of its emollient, water-absorptive, and emulsifying properties. It enhances stability, improves texture, and increases consistency. The emollient properties are due to absorption and retention of cetyl alcohol in the epidermis, where it lubricates and softens the skin while imparting a characteristic ‘velvety’ texture. Cetyl alcohol is also used for its water absorption properties in water-in-oil emulsions. For example, a mixture of petrolatum and cetyl alcohol (19 : 1) will absorb 40–50% of its weight of water. Cetyl alcohol acts as a weak emulsifier of the water-in-oil type, thus allowing a reduction of the quantity of other emulsifying agents used in a formulation. Cetyl alcohol has also been reported to increase the consistency of water-in-oil emulsions. In oil-in-water emulsions, cetyl alcohol is reported to improve stability by combining with the water-soluble emulsifying agent. The combined mixed emulsifier produces a close packed, monomolecular barrier at the oil–water interface which forms a mechanical barrier against droplet coalescence. In semisolid emulsions, excess cetyl alcohol combines with the aqueous emulsifier solution to form a viscoelastic continuous phase that imparts semisolid properties to the emulsion and also prevents droplet coalescence. Therefore, cetyl alcohol is sometimes referred to as a ‘consistency improver’ or a ‘bodying agent’, although it may be necessary to mix cetyl alcohol with a hydrophilic emulsifier to impart this property. It should be noted that pure or pharmacopeial grades of cetyl alcohol may not form stable semisolid emulsions and may not show the same physical properties as grades of cetyl alcohol that contain significant amounts of other similar alcohols. See Section 4. See Table I.
Cetyl alcohol occurs as waxy, white flakes, granules, cubes, or castings. It has a faint characteristic odor and bland taste.
See Table II.
Boiling point 316–3448C; 300–3208C for Nacol 16-95; 310–3608C for Speziol C16 Pharma; 3448C for pure material. Density 0.908 g/cm3 ; 0.805-0.815 g/cm3 for Speziol C16 Pharma. Flash point 1658C Melting point 45–528C; 498C for pure material. Refractive index n D 79 = 1.4283 for pure material. Solubility Freely soluble in ethanol (95%) and ether, solubility increasing with increasing temperature; practically insoluble in water. Miscible when melted with fats, liquid and solid paraffins, and isopropyl myristate. Specific gravity 0.81 at 508C Viscosity (dynamic) 7 mPa s (7 cP) at 508C; 8 mPa s (8 cP) at 608C for Nacol 16-95
Cetyl alcohol is stable in the presence of acids, alkalis, light, and air; it does not become rancid. It should be stored in a well-closed container in a cool, dry place.
Incompatible with strong oxidizing agents. Cetyl alcohol is responsible for lowering the melting point of ibuprofen, which results in sticking tendencies during the process of film coating ibuprofen crystals.(1)
Cetyl alcohol may be manufactured by a number of methods such as esterification and hydrogenolysis of fatty acids or by catalytic hydrogenation of the triglycerides obtained from coconut oil or tallow. Cetyl alcohol may be purified by crystallization and distillation.
Cetyl alcohol is mainly used in topical formulations, although it has also been used in oral and rectal preparations. Cetyl alcohol has been associated with allergic delayed-type hypersensitivity reactions in patients with stasis dermatitis.(2) Crosssensitization with cetostearyl alcohol, lanolin, and stearyl alcohol has also been reported.(3,4) It has been suggested that hypersensitivity may be caused by impurities in commercial grades of cetyl alcohol since highly refined cetyl alcohol (99.5%) has not been associated with hypersensitivity reactions.(5) LD50 (mouse, IP): 1.6 g/kg(6) LD50 (mouse, oral): 3.2 g/kg LD50 (rat, IP): 1.6 g/kg LD50 (rat, oral): 5 g/kg
Observe normal precautions appropriate to the circumstances and quantity of material handled. Eye protection and gloves are recommended
Included in the FDA Inactive Ingredients Database (ophthalmic preparations, oral capsules and tablets, otic and rectal preparations, topical aerosols, creams, emulsions, ointments and solutions, and vaginal preparations). Included in nonparenteral medicines licensed in the UK. Included in the Canadian List of Acceptable Nonmedicinal Ingredients.
Cetostearyl alcohol; stearyl alcohol.
The EINECS number for cetyl alcohol is 253-149-0. The PubChem Compound ID (CID) for cetyl alcohol is 2682.