Cetyl Alcohol, Cetanol

Category

Coating Agents; Emulsifying Agents; Stiffening Agents

Molecular Formula

C16H34O

Molecular Weight

242.44

Grade

Pharmceutical Excipients

Description

Cetyl alcohol occurs as waxy, white flakes, granules, cubes, or castings. It has a faint characteristic odor and bland taste.

UNII

936JST6JCN

Chemical Name

Hexadecan-1-ol

CAS Number

36653-82-4

Synonyms

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

Administration route

Ophthalmic, oral, otic and rectal, topical aerosols, vaginal

Dosage Form

Ophthalmic preparations, oral capsules and tablets, otic and rectal preparations, topical aerosols, creams, emulsions, ointments and solutions, and vaginal preparations

Stability and Storage Conditions

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.

Source and Preparation

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.

Applications

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, mono molecular 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.

Safety

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.Crosssensitization with cetostearyl alcohol, lanolin, and stearyl alcohol has also been reported.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. LD50 (mouse, IP): 1.6 g/kg LD50 (mouse, oral): 3.2 g/kg LD50 (rat, IP): 1.6 g/kg LD50 (rat, oral): 5 g/kg

Incompatibilities

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.