The influence of the tobacco additives diammonium hydrogen phosphate (DAP) and urea on the delivery and respiratory tract retention of nicotine and solanesol and on the uptake of nicotine into venous blood was investigated in 10 smokers under mouth-hold and 75 and 500 mL inhalation conditions. Three cigarettes with identical physical specifications were produced from a common lamina tobacco blend. The control cigarette contained nonammoniated reconstituted tobacco sheet (RTS), whereas DAP and other ammonia compounds were added to the RTS of the second cigarette. Urea was added to the tobacco of the third cigarette. The presence of DAP or urea in the test cigarettes did not significantly influence solanesol retention within the mouth during the mouth-hold condition. Nicotine retention within the mouth during the mouth-hold condition was, however, significantly higher for the DAP cigarette (64.3 +/- 10.5%) than for the urea (53.3 +/- 11.3%) or control cigarette (46.3 +/- 8.6%), but this did not result in an increase in nicotine uptake into venous blood. Solanesol retentions during the 75 and 500 mL inhalation volume conditions and nicotine retentions during the 75 mL inhalation volume condition were not significantly different for the three cigarette types. Although the nicotine retention approached 100% with each cigarette type during the 500 mL inhalation condition, the nicotine retention for the urea-treated cigarette (99.6 +/- 0.2%) was marginally, but statistically, significant, higher than for the control (99.1 +/- 0.5%) and DAP-treated cigarettes (98.8 +/- 0.6%). There were no statistically significant differences between the indices of nicotine uptake into venous blood for the three cigarette types in any of the inhalation conditions.

Abstract The influence of inhalation depth and breath-hold duration on the retention of nicotine and solanesol in the human respiratory tract and on nicotine uptake was studied in ten cigarette smokers. In a first series of experiments, the subjects took seven puffs from a 10 mg ‘tar’ yield, test cigarette and a fixed volume of air (0, 75, 250, 500 or 1000 mL, as required by the protocol) was inhaled after each puff in order to give a controlled ‘depth’ of inhalation. The inhalation was drawn from a bag containing the required volume of air. Following a 2 s breath-hold, subjects exhaled normally, with the first exhalation after each puff passing through a single acidified filter pad for collection of the non-retained nicotine and solanesol. Blood samples were taken before and at intervals during and after smoking for the sessions with 0, 75 and 500 mL inhalation volumes for determination of plasma nicotine and carboxyhaemoglobin levels. Another series of experiments was conducted with a fixed inhalation volume (500 mL) and two further breath-hold durations (0 and 10 s) in addition to 2 s from above. Nicotine and solanesol retentions were measured for each breath-hold condition. The amounts of nicotine retained within the respiratory system, expressed as a percentage of the amount taken into the mouth, were consistently higher than the corresponding values for solanesol in all five inhalation conditions (0-1000 mL, 2 s breath-hold). Nicotine retention increased from 46.5% at zero inhalation to 99.5% at 1000 mL inhalation (2 s breath-hold) and from 98.0% at zero breath-hold to 99.9% at 10 s breath-hold (500 mL inhalation). Solanesol retention increased from 34.2% at zero inhalation volume to 71.9% at 1000 mL inhalation (2 s breath-hold) and from 51.8% at zero breath-hold to 87.6% at 10 s breath-hold (500 mL inhalation). Plasma nicotine decreased from pre-smoking levels after zero inhalation indicating that the nicotine retained within the mouth was poorly absorbed into the systemic circulation. After 75 mL inhalation, plasma nicotine levels were significantly greater than for zero inhalation but not significantly less than after 500 mL inhalation except at the time of maximum nicotine concentration. As in every experimental condition, a higher percentage of nicotine than solanesol was retained within the respiratory tract, it was concluded that the difference in retention of the moderately volatile nicotine and the non-volatile solanesol is consistent with the concept of nicotine evaporation from smoke particles and the subsequent efficient retention in the airways of gaseous nicotine. The retention of solanesol followed the expected pattern of particulate deposition i.e., an increase with both increasing depth of inhalation and breath-hold duration. However, nicotine retention was almost complete even at shallow inhalations and short breath-hold durations.

Abstract The Smoking Behaviour Sub Group of the Cooperation Centre for Scientific Research Relative to Tobacco (CORESTA) was set up in 1996 with the aims of reviewing information relevant to smoking behaviour, publishing the reviews, identifying gaps in information and suggesting suitable studies. So far three reviews have been published by members of the sub group (1-3) and other reviews are in progress. One aspect of the subject that has become apparent to the sub group is that terms are used inconsistently in various papers on smoking behaviour. We therefore propose that the following terms and their definitions are used in the future.

Exposure to tobacco smoke is measured by a variety of invasive and noninvasive techniques. Our purpose was to examine how well some of these measures correlated when obtained simultaneously from the same subjects. On three occasions, six subjects were studied while they were smoking a single cigarette after 24 hr of abstinence. There were positive correlations between increases in heart rate and plasma nicotine concentrations and between percentage carboxyhemoglobin and exhaled carbon monoxide. Although residual cotinine was readily detected in samples of plasma before the subjects smoked, there was an increase in mean levels, with a peak approximately 1 hr after smoking. Urinary concentrations of nicotine, cotinine, and nicotine-1'-N-oxide and thiocyanate levels in plasma and saliva were essentially unchanged by smoking a single cigarette. Data on smoke generation and nicotine retention in cigarette butts correlated poorly with all other measures of smoke uptake.

A method is described for the rapid determination of benzo[a]pyrene in the particulate phase of cigarette smoke. The particulate matter from five cigarettes is fractionated on Florisil and a concentrated fraction injected on to a high-performance liquid chromatography column of Partisil. Benzo[a]pyrene is detected in the eluate fluorimetrically. Quantification is achieved by means of a standard-additions method.