💊 Chemical information
E904; Goma laca; Gomme Laque; Gommes laques; Lacca; Lacca in Tabulis; Schellack; Šelak; Šelakas; Sellak; Shellack; Shellakka.
CAS — 9000-59-3.
Pharmacopoeias.In Eur.. Also in USNF. Jpn includes Purified Shellac and White Shellac (Bleached).
Ph. Eur. 6.2(Shellac). It is obtained by purification of the resinous secretion of the female insect Kerria lacca (Kerr) Lindinger (Laccifer lacca Kerr). There are 4 types of shellac depending on the nature of the treatment of crude secretion (seedlac): Waxcontaining Shellac; Bleached Shellac; Dewaxed Shellac; and Bleached, Dewaxed Shellac. Brownish-orange or yellow, shining, translucent, hard or brittle more or less thin flakes (Wax-containing Shellac; Dewaxed Shellac), or a creamy-white or brownish-yellow powder (Bleached Shellac; Bleached, Dewaxed Shellac). Practically insoluble in water. With dehydrated alcohol it gives a more or less opalescent solution (Wax-containing Shellac; Bleached Shellac) or a clear solution (Dewaxed Shellac; Bleached, Dewaxed Shellac). When warmed, it is sparingly soluble or soluble in alkaline solutions. Protect from light. Store Bleached Shellac and Bleached, Dewaxed Shellac at a temperature not exceeding 15°.
USNF 26(Shellac). It is obtained by purification of lac, the resinous secretion of the insect Laccifer lacca kerr (Coccidae). There are 4 varieties: Orange Shellac, Dewaxed Orange Shellac, Regular Bleached (White) Shellac, and Refined Bleached Shellac. Orange Shellac occurs as thin, hard, brittle, transparent, pale lemon-yellow to brownish-orange flakes, having little or no odour. Bleached Shellac occurs as opaque, amorphous, cream to yellow granules or coarse powder, having little or no odour. Insoluble in water; very slowly soluble in alcohol, 85 to 95% (w/w); soluble in ether, 13 to 15%, in petroleum spirit, 2 to 6%, in benzene, 10 to 20%, and in aqueous solutions of ethanolamines, alkalis, and borax; sparingly soluble in turpentine oil. Store preferably at a temperature not exceeding 8°.
Shellac is used as an enteric coating for pills and tablets, but disintegration time has been reported to increase markedly on storage.
USNF 26: Pharmaceutical Glaze.
Published May 08, 2019.