Overview Of Program, 1967

Robert J. Johnson, a senior scientist with B&W research and development, summarizes a June 20, 1967, meeting at which BAT's past and present research on nicotine was discussed. Johnson described six separate areas of research on nicotine that members of the BAT R&D group at Southampton had on their agenda:

Project ARIEL —This is dormant for the moment. The first samples tried gave a tremendous kick, even though the nicotine delivery was quite small. It would appear that the project will be reinitiated within a few months.

Dr. S. R. Evelyn is presently investigating the absorption of extractable and non-extractable nicotine in the mouth, albeit with a mechanical mouth.

Dr. J. D. Backhurst is setting up an analysis for pH of whole smoke on a puff-by-puff basis. This correlates with his previous interest in extractable nicotine[.]

Mr. H. G. Horsewell continues to work with alkaline filter additives which selectively increase nicotine delivery.

Dr. R. E. Thornton will be synthesizing ring-labeled nicotine as his first project in the new radiochemical facilities. This will initially be to determine the percentage of nicotine which is destroyed during smoking.

Dr. D. J. Wood will be assigning the new physiologist to a study into the organoleptic [sensory, especially irritation] effects of nicotine. {1201.01, pp. 10–11}

The research program was concerned with understanding the delivery of nicotine in smoke and its absorption. The organoleptic work described comes closer than anything else in the documents to suggesting an interest in the taste and flavor of nicotine, but it actually seems to be more concerned with understanding the irritating properties of nicotine on mucous membranes. This is an important problem in cigarette design, since alkaline nicotine, which is readily absorbed in the mouth, is also irritating to the throat (13).

Some of the internal research reports for the work in progress mentioned by Dr. Johnson were available to us in summary form. These reports deal mainly with the absorption of nicotine.

A 1966 report describes "Further Work on 'Extractable' Nicotine" {1205.10}. Nicotine that is "extractable" (more soluble in chloroform than water) proved to be a better gauge of perceived "strength" by the smoker than whole nicotine content. Most "extractable" nicotine was recognized to be nicotine base, so the "nonextractable" nicotine was the acidic salt. The report speculates on why "extractable" nicotine has a greater perceived strength:

The reasons for the relationship between smoker response and "extractable" nicotine content of the smoke remain obscure. Several possible explanations have been considered and, at the present time, it would appear that the increased smoker response is associated with nicotine reaching the brain more quickly. {1205.01, p. 1}

It is now widely recognized that what BAT scientists were calling "extractable nicotine," nicotine base (also called free nicotine or unionized nicotine), is readily absorbed in the mouth and nose, while the ionized form that exists in acidic environments is hardly absorbed at all in the mouth (3). The internal research reports indicate that BAT had a sophisticated understanding of this distinction thirty years ago.

A series of reports from 1968 and 1969 document the interest of the research scientists at BAT in the variables that account for nicotine absorption in the mouth, as from pipe and cigar smoke {1214.01; 1205.05; 1205.06}. Nicotine retention in the mouth was found to be a function of the pH (acidity) of the smoke, while absorption was a function of the pH of saliva. "Extractable nicotine content" was directly related to pH. The design criterion for the membrane used in the artificial mouth was that it permit the passage of unionized (free-base) nicotine but not that of ionized nicotine (salt) {1214.01, p. 12}. An appropriate imitation of the way an actual mouth works, absorbing unionized but not ionized nicotine, was an explicit feature for the model system. This is yet another indication that the scientists at BAT knew the importance of nicotine absorption. The last report in this series notes that, in contrast to pipe and cigar smokers, cigarette smokers usually inhale {1205.06}.

These research reports put flesh on Dr. Johnson's brief summary and demonstrate that in the late 1960s BAT's R&DE had a tremendous interest in achieving a better understanding of how nicotine is best absorbed into the body from pipes, cigars, and cigarettes.