Washington DC
CRITICS of the tobacco industry who argue that cigarettes are manufactured to
enhance the addictive effect of nicotine have received a boost. New research has
confirmed that adding ammonia to tobacco鈥攁 technique similar to that of
鈥渇reebasing鈥� cocaine鈥攇reatly increases the ability of nicotine to enter a
smoker鈥檚 bloodstream.
James Pankow, of the Oregon Graduate Institute of Science and Technology in
Beaverton, says his research, published in this month鈥檚 issue of
Environmental Science and Technology (vol 31, p 2428), was inspired by
Congressional hearings into the American tobacco industry held in 1994. At these
hearings, the Food and Drug Administration quoted from one company鈥檚
鈥渓eaf-blender鈥檚 manual鈥� which described how ammonia would boost the 鈥渋mpact鈥� of
nicotine in the leaf. However, the companies have insisted that ammonia is used
to reduce the total amount of nicotine in the tobacco.
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Nicotine in tobacco is mostly in the form of nonvolatile salts. Pankow says
that ammonia liberates pure nicotine from these salts, allowing it to evaporate
more easily, disperse through the lungs and be easily absorbed into the blood.
Even if it remains as solid particles in the smoke, he says, the 鈥渓iberated鈥�
nicotine dissolves better in fats, allowing it to pass more easily through the
membranes lining the lungs.
Pankow collected particles from cigarette smoke on filter papers. He then
added varying quantities of ammonia to the papers and measured how much nicotine
evaporated. The greater the level of ammonia, the more gaseous nicotine was
given off.
The tobacco in a typical cigarette contains about 3 per cent ammonia. From
his data, Pankow calculates that this would force about 25 per cent of the
nicotine in inhaled smoke into the gaseous form. This is a hundred times the
amount that would evaporate without the addition of ammonia.
The effect, Pankow says, is similar to what happens with freebase forms of
cocaine. Powdered cocaine is also a salt, cocaine hydrochloride. In one method
of freebasing, ammonia is added to liberate the pure drug. In another, the
powder is mixed with sodium bicarbonate, forming the white solid known as
crack.