Stearyl Alcohol

Basic Information

Name: Stearyl Alcohol

CAS No: 1-Octadecanol [112-92-5

Functional Categories

Stiffening agent

1. Nonproprietary Names

BP: Stearyl Alcohol JP: Stearyl Alcohol PhEur: Stearyl Alcohol USP-NF: Stearyl Alcoho

2. Synonyms

Alcohol stearylicus; Cachalot; Crodacol S95; Hyfatol 18-95; Hyfatol 18-98; Lanette 18; Lipocol S; Lipocol S-DEO; Nacol 18- 98; Nacol 18-98P; n-octadecanol; octadecyl alcohol; Rita SA; Speziol C18 Pharma; Stearol; Stenol; Tego Alkanol 18; Vegarol 1898.

3. Chemical Name & CAS Registry

1-Octadecanol [112-92-5

4. Empirical Formula & Molecular Weight

C18H38O 270.48 (for pure material)

5. Structural Formula

6. Applications

Stearyl alcohol is used in cosmetics(1,2) and topical pharmaceutical creams and ointments as a stiffening agent. By increasing the viscosity of an emulsion, stearyl alcohol increases its stability. Stearyl alcohol also has some emollient and weak emulsifying properties, and is used to increase the water-holding capacity of ointments, e.g. petrolatum. In addition, stearyl alcohol has been used in controlled-release tablets,(3,4) suppositories,(5,6) and microspheres.(7,8) It has also been investigated for use as a transdermal penetration enhancer.(9)

7. Description

Stearyl alcohol occurs as hard, white, waxy pieces, flakes, or granules with a slight characteristic odor and bland taste

8. Pharmacopeial Specifications

See Table I

9. Typical Properties

Autoignition temperature 4508C Boiling point 210.58C at 2 kPa (15 mmHg) Density (true) 0.884–0.906 g/cm3 (10) Flash point 1918C (open cup) Freezing point 55–578C Melting point 59.4–59.88C for the pure material. Refractive index nD 60 = 1.4388 at 608C Solidification point 56–598C for Nacol 18-98; 55–588C for Speziol C18 Pharma. Solubility Soluble in chloroform, ethanol (95%), ether, hexane, propylene glycol, benzene, acetone, and vegetable oils; practically insoluble in water. Vapor pressure 133.3 Pa (1 mmHg) at 150.38C Viscosity (dynamic) 9.82 mPa s at 648C(10) (results of a laboratory project for the third edition)

10. Stability & Storage

Stearyl alcohol is stable to acids and alkalis and does not usually become rancid. It should be stored in a well-closed container in a cool, dry place.

11. Incompatibilities

Incompatible with strong oxidizing agents and strong acids.

12. Method of Manufacture

Historically, stearyl alcohol was prepared from sperm whale oil but is now largely prepared synthetically by reduction of ethyl stearate with lithium aluminum hydride

13. Safety

Stearyl alcohol is generally considered to be an innocuous, nontoxic material. However, adverse reactions to stearyl alcohol present in topical preparations have been reported. These include contact urticaria and hypersensitivity reactions, which are possibly due to impurities contained in stearyl alcohol rather than stearyl alcohol itself.(11–15) The probable lethal oral human dose is greater than 15 g/kg. LD50 (rat, oral): 20 g/kg(16

14. Handling Precautions

Observe normal precautions appropriate to the circumstances and quantity of material handled. Eye protection and gloves are recommended. Stearyl alcohol is not a fire hazard, although it will burn and may give off noxious fumes containing carbon monoxide

15. Regulatory Status

Included in the FDA Inactive Ingredients Database (oral tablets, rectal topical, and vaginal preparations). Included in nonparenteral medicines licensed in the UK. Included in the Canadian List of Acceptable Non-medicinal Ingredients.

16. Related Substances

Cetostearyl alcohol; cetyl alcohol.

17. Comments

The EINECS number for stearyl alcohol is 204-017-6. The PubChem Compound ID (CID) for stearyl alcohol is 8221.