Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

OHSU researcher publishes first measurements of "free-base" nicotine in cigarette smoke

25.07.2003


James F. Pankow, Ph.D., professor of environmental and biomolecular systems at OHSU’s OGI School of Science & Engineering in Hillsboro, Ore., and a member of the OHSU Cancer Institute


Thought to be the most addictive form of nicotine in tobacco smoke, free-base nicotine is found at a wide range of levels in popular brands

When it comes to nicotine content, all cigarettes are not created equal, according to a new study by researchers at Oregon Health & Science University. In fact, the study finds that some commercial cigarette brands contain 10 to 20 times higher percentages of nicotine in the so-called "free-base" form -- the form thought to be most addictive -- than believed up to now. The study, published today in the online edition of the American Chemical Society´s journal Chemical Research in Toxicology, documents the first reliable measurements of free-base nicotine in tobacco smoke.

"We believe that this study is a major step forward in understanding how addictive nicotine is delivered by tobacco smoke," said James F. Pankow, Ph.D., professor of environmental and biomolecular systems at OHSU´s OGI School of Science & Engineering in Hillsboro, Ore., and a member of the OHSU Cancer Institute. "We found big differences in the percentages of free-base nicotine among 11 commercial cigarette brands."



Nicotine enters a smoker´s body mostly carried on the billions of particles in cigarette smoke, Pankow said. In common with street drugs like cocaine, he said, nicotine´s molecular structure can appear in both free-base ("unprotonated") and non-free-base ("monoprotonated") forms. The difference is that the free-base form is missing a hydrogen ion, and this allows it to vaporize easily into a gas during smoking. "During smoking, only the free-base form can volatize from a particle into the air in the respiratory tract. Gaseous nicotine is known to deposit super-quickly in the lungs. From there, it´s transported rapidly to the brain.

"Since scientists have shown that a drug becomes more addictive when it is delivered to the brain more rapidly," Pankow continued, "free-base nicotine levels in cigarette smoke thus are at the heart of the controversy regarding the tobacco industry´s use of additives like ammonia and urea, as well as blending choices in cigarette design." A 1997 Pankow study resulted in the first public-domain report linking ammonia additives with increased free-base nicotine levels.

In the new study, Pankow analyzed the smoke of popular cigarette brands under controlled conditions to measure what percentage of the nicotine is in the more addictive free-base form. It employed a laboratory smoking device and a gas chromatograph-mass spectrometer (GC-MS) to collect and analyze smoke from 11 brands of cigarettes purchased at various U.S. retail outlets. These cigarettes were tested against a "reference" cigarette -- a standardized cigarette used only by scientists in tobacco and smoking research. The researchers made brand-to-brand comparisons, measuring the first three puffs of smoke from each brand separately from the remaining smoke. The first few puffs, Pankow said, "are in some cases much higher in this free-base nicotine fraction."

Measurements ranged from about 1 percent free-base nicotine in the first few puffs of the reference cigarette to 36 percent for a specialty U.S. brand. One type of Marlboro, the leading U.S. brand of king-sized filter cigarettes, contained about 10 percent free-base nicotine, Pankow said.

The study found a wide range of free-base nicotine levels among other brands such as Camel, Winston, Doral, GPC, Kamel Red, Virginia Slims, American Spirit and the French brand Gauloises. (A copy of the complete study is available upon request; see the last page for details).

Neal Benowitz, M.D., a nicotine addiction expert at the University of California at San Francisco School of Medicine, provided a scientific perspective of this study´s impact:

"The rate of absorption of nicotine from a tobacco product into the blood stream influences the addictiveness of the product, and the rate of absorption of nicotine from cigarette smoke is dependent on how much of the nicotine is in the free-base form. Free-base nicotine levels are determined by the pH (acid-base balance) of the smoke, which is difficult to measure accurately and which can be influenced by various additives. Pankow and colleagues have analyzed free-base nicotine and pH in a number of popular cigarette brands, using a novel method that is much more accurate than methods used previously. They found more than 10-fold variation in levels of free-base nicotine among American cigarette brands. This is the first research to make such observations and will certainly help to guide future research into differences in the addictiveness of different brands of cigarettes."

Internal documents made public through the 1999 tobacco settlement show that some industry scientists have long been aware of the role of free-base nicotine in cigarette smoke. For example, one report in the Legacy Tobacco Documents Library states:

"In essence, a cigarette is a system for delivery of nicotine to the smoker in attractive, useful form. At `normal´ smoke pH, at or below about 6.0, essentially all of the smoke nicotine is ... relatively slowly absorbed by the smoker. As the smoke pH increases above about 6.0, an increasing proportion of the total smoke nicotine occurs in "free" form, which is volatile, rapidly absorbed by the smoker, and believed to be instantly perceived as nicotine "kick," R. J. Reynolds Tobacco Company, 1974.

Pankow notes that most addiction researchers believe that chemicals like nicotine, cocaine and methamphetamine become increasingly addictive the more rapidly they are delivered to the brain. Addiction expert Jack Henningfield, Ph.D., a professor at the Johns Hopkins University School of Medicine and former adviser to past FDA Commissioner David Kessler, M.D., J.D., said Pankow has shown that " cigarettes deliver much higher levels of free-base nicotine than previously thought, thus helping to explain their enormous addictive potential. In fact, the study shows that the modern cigarette does to nicotine what crack does to cocaine. It appears likely that ingredients used in modern cigarette manufacture such as ammonia and urea account for this addiction-enhancing effect."

According to Greg Connolly, D.M.D., M.P.M., director of the Massachusetts Tobacco Control Program, the study "will allow a consideration of the regulation of the addictive properties of cigarettes in a way that has never before been possible."

Coincidentally, the study comes on the heels of a recent controversy in Europe over the disclosure of tobacco ingredients. Last week, Dutch Health Minister Han Hoogervorst ordered tobacco manufacturers to make public all ingredients used in cigarettes, cigars and loose tobacco sold in the Netherlands, and to reveal which ingredients are addictive. The new rule -- which also applies to foreign-based companies -- was issued over the protests of tobacco companies concerned about the disclosure of proprietary product information. According to an April 25 Reuters report, BAT Netherlands, a subsidiary of the tobacco giant British American Tobacco, objected to the disclosure of additives used in cigarettes sold in the Dutch market. A spokesman for the company stated:

"... to our understanding this requirement goes beyond what was required by the EU directive and it is most detrimental to our position vis-a-vis our competitors, and certain information cannot be declared . . . ."

Dutch officials stated that the government would not reveal specific tobacco formulations, preventing competitors from copying a specific brand of cigarette. In the United States, there are no formal tobacco industry or FDA guidelines covering the appropriate levels of free-base nicotine in cigarettes, Pankow said. "But the `conventional wisdom´ put forth by the industry in the past suggested small percentages of free-base nicotine," he said.

"Cigarette smoking is the single most preventable cause of morbidity and mortality in the United States," said Grover C. Bagby, Jr., M.D., director of the OHSU Cancer Institute. "Understanding the chemical elements that form the basis of addiction is an important step forward in developing ways of conquering this problem in our society today."

Mike MacRae | EurekAlert!
Further information:
http://legacy.library.ucsf.edu/tid/rte53d00

More articles from Health and Medicine:

nachricht New High-Performance Center Translational Medical Engineering
26.04.2017 | Fraunhofer ITEM

nachricht A promising target for kidney fibrosis
21.04.2017 | Brigham and Women's Hospital

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

Scientist invents way to trigger artificial photosynthesis to clean air

26.04.2017 | Materials Sciences

Ammonium nitrogen input increases the synthesis of anticarcinogenic compounds in broccoli

26.04.2017 | Agricultural and Forestry Science

SwRI-led team discovers lull in Mars' giant impact history

26.04.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>