Literatus: Glaze of the ‘lac’ bug-A A +A
Tuesday, March 12, 2013
AMERICAN poet William Carlos Williams wrote: “Old age is a flight of small cheeping birds skimming bare trees above a snow glaze.”
Many Filipinos may not know how a snow glaze looks like; but one common glaze that Filipinos are familiar with can be seen in furniture. And we call that glaze “shellac.”
What most Filipinos, even those who have actually seen a snow glaze, may not know is this: the glaze of shellac has been fairly used in pharmaceutical products. The flakes come from the resin that the female Laccifer bug (Kerria lacca or just lac) secrete on trees in the forests of India, Thailand and Burma (now Mynmar). It takes about 100,000 lac bugs to make 500 grams of shellac flakes.
Shellac is a natural bioadhesive, chemically similar to the synthetic polymers we call “plastic.” In a sense, shellac is a natural form of plastic. And it is used as a glazing agent on tablets and capsules. It contains denatured alcohol, which dissolves the 20-51 percent shellac component.
It has acidic properties that make it resistant to stomach acids, and is a useful coating for controlled-release tablets. It protects the tablet from moisture, extends its shelf life, among others.
The United States Food and Drug Administration classified shellac as "generally recognized as safe" (Gras). However, a study conducted by the Food and Drug Research Laboratories in 1984 noted enlargement of cecum or swelling of proximal colon, in rats fed with 13.2 gram shellac per day for 90 days. A study in 1979 also observed more pus-formation in the moist lining of the gastrointestinal tract. A forensic autopsy of a 55-year old male cabinet maker found a hardened mass of shellac in his stomach. Such mass can cause anorexia, weight loss, bleeding or perforation.
The shellac chemistry seems to show no toxicity in human consumption level. But long-term intake or exposure may accumulate in the stomach. How? It is still not known; so few studies are available on this.
In-Pharma Technologist.com, an online reference website, reported shellac as hardly used in drugs as early as 2003 in the United States. By 1996, only 73 products used it from 278 listings 10 years prior. In the Philippines certain tablets still contain it, though; just check the literature inserts for information (some manufacturers disclose this inactive ingredient).
Perhaps, amidst the uncertainty, old age may not be unattainable, after all, despite the intake of shellac. As American poet Allen Tate wrote in one of his poem:
The young men who watch us from the curbs:
They hold the glaze of wonder in their stare.
Published in the Sun.Star Cebu newspaper on March 13, 2013.