Shellac

Scientific Name(s): Laccifer lacca
Common Name(s): Gommelaque, Lac, Lacca, Shellac

Medically reviewed by Drugs.com. Last updated on Sep 13, 2021.

Clinical Overview

Use

The most common use is as a furniture finish, but it has also been used in the pharmaceutical industry, in dentistry, and in cosmetics.

Dosing

There is no clinical evidence to support specific doses of shellac for therapeutic purposes.

Contraindications

Contraindications have not yet been identified.

Pregnancy/Lactation

Information regarding safety and efficacy in pregnancy and lactation is lacking.

Interactions

None well documented.

Adverse Reactions

Little data are available. Several cases of allergic contact dermatitis of the eyelids due to shellac in mascara and one report of contact cheilitis have been documented.

Toxicology

Shellac NF is food grade and is listed as Generally Recognized as Safe (GRAS) by the FDA.

Scientific Family

• Coccidae

Source

Shellac is the purified product of lac, the red, hardened secretion of the insect Laccifer (Tachardia) lacca Kerr. This tiny insect sucks the sap of selected trees and bushes, and secretes lac as a protective covering. The name lac is said to derive from lakh, the Sanskrit word for one hundred thousand, a reference to the very large number of insects involved in producing appreciable amounts of the product.1

Lac is cultivated in India, Thailand, and Burma. The whitest lac is produced by insects infesting the kusum tree (Schleichera trijuga). The harvester cuts twigs coated with lac into small pieces called sticklac. The crude material is ground and soaked in water to remove debris and insect bodies. The remaining material is soaked in sodium carbonate, which removes laccaic acid, a complex mixture of at least four structurally related pigments. The resulting granules retain the yellow pigment erythrolaccin and are dried to form seedlac. Further treatment by melting, evaporating, or filtering yields shellac.2

History

Shellac is most often used as a finish for fine furnitures. Further, the material has been used for almost 100 years by the pharmaceutical industry. Examples of shellac's role in this field include: Tablet coating formulations,3, 4, 5, 6 microencapsulation,7, 8, 9, 10, 11 matrix formation,12 enteric coating,13 humidity tolerance,14 and binding ability.15

Shellac is used in dentistry, as a binding agents for dentures, restorations, and mouldings, and for training purposes in dental schools.16, 17, 18, 19, 20, 21, 22

Shellac has also been used as an ingredient in hair spray and in other cosmetics23, 24 However, shellac undergoes an aging effect upon storage and thus has fallen into disfavor as an ingredient in some preparations.2

Chemistry

The National Formulary XV recognizes 4 grades of shellac: Orange, dewaxed orange, regular bleached and refined wax-free bleac...