Pharmaceutical glaze is an alcohol based solution of various types of food grade shellac. When used in food and confections, it is also known as confectioner's glaze, resinous glaze, pure food glaze and natural glaze. It is also known colloquially in the manufacturing world as beetle juice due to shellac's derivation from the lac insect Kerria lacca (which is not a beetle, but a scale insect).
Pharmaceutical glaze may contain denatured alcoholic solution of 20-51% shellac, waxes and titanium dioxide as an opacifying agent.
Pharmaceutical glaze is used by the drug and nutritional supplement industry as a coating material for tablets and capsules. It serves to improve the product's appearance, extend shelf life and protect it from moisture, as well as provide a solid finishing film for pre-print coatings. It also serves to mask unpleasant odors and aid in the swallowing of the tablet.
The shellac coating is insoluble in stomach acid and may make the tablet difficult for the body to break down or assimilate. For this reason it can also be used as an ingredient in time-released, sustained or delayed action pills. The product is listed on the U.S. Food and Drug Administration's inactive ingredient list.
A competitive non-animal-based product is zein, a corn protein.