Rapid and sensitive high-performance liquid chromatographic determination of nicotine and cotinine in nonsmoker human and rat urines

A simple reversed-phase high-performance liquid chromatographic method with paired-ion and UV detection has been developed for the rapid quantification of urinary nicotine and cotinine. A one-step solid-liquid extraction on Extrelut was used. Separation from endogenous substances was achieved with a decreasing flow-rate. With 20 ml of urine for extraction, the limit of quantification was 0.5 ng/ml for cotinine and 5 ng/ml for nicotine; linearity was obtained from 50 to 5000 ng/ml. The intra- and inter-day coefficients of variation were less than 9% for cotinine and 30% for nicotine. Average recoveries for cotinine were 92-100% and 47-86% for nicotine. The present method was applied to the urine analysis of smokers, nonsmoker children, and experimental animals.

Rapid method for the simultaneous measurement of nicotine and cotinine in urine and serum by gas chromatography-mass spectrometry

A simple, sensitive, and rapid gas chromatographic-mass spectrometric method is described for the simultaneous detection and quantitation of nicotine and its metabolite, cotinine, in urine and serum. The analytes and their respective deuterated internal standards were extracted by liquid-liquid extraction coupled to centrifugation and evaporation. The detection limit of the assay was 0.16 ng/ml for both nicotine and cotinine. The limit of quantitation for each analyte was 1.25 ng/ml.

Assessment of simple colorimetric procedures to determine smoking status of diabetic subjects

The performance of a simple colorimetric assay for urinary nicotine metabolites to assess smoking status in diabetic subjects (n = 251) was investigated. Several variations of the colorimetric assay and a qualitative extraction procedure were evaluated in comparison with a cotinine immunoassay as the "gold standard." Among these, the best overall performance was achieved with the qualitative test (sensitivity 95%; specificity 100%). The quantitative measurement of total nicotine metabolites performed less well (sensitivity 92%; specificity 97%) but could be improved by incorporating a blank extraction (sensitivity 98%; specificity 98%). Allowance for diuresis appeared to offer no advantage over the other methods. These results support previous findings regarding the use of these colorimetric procedures in nondiabetic subjects and, contrary to other recent observations, their performance was not impaired in diabetic patients.

Increasing urinary cotinine concentrations at elevated temperatures: the role of conjugated metabolites

The presence of cotinine, a nicotine metabolite, in urine above a specified cutoff concentration is commonly used to distinguish smokers from nonsmokers, as in smoking cessation studies. A stability study of cotinine in urine was carried out after questions arose concerning analyte stability at elevated storage and shipment temperatures. Aliquots from a smokers urine pool were stored at 5, 25, 40, 50 and 60 degrees C for 30 days. Another set of aliquots, obtained by diluting the smokers pool 1:1 with nonsmokers urine, were stored under the same conditions. Free cotinine levels, determined by a stability-indicating gas chromatographic/mass spectrometric (GC/MS) assay, increased over the 30-day period at higher storage temperatures. Cotinine concentrations in the aliquots stored at 60 degrees C, for example, nearly doubled over 30 days (1301 to 2476 ng/ml), with similar proportional increases observed in the aliquots diluted with nonsmokers urine. Since cotinine can be excreted to a large degree as cotinine-N-glucuronide, this conjugated metabolite was determined by an indirect method. As the storage temperature increased, the free/conjugated cotinine ratio dramatically increased, pointing to cotinine-N-glucuronide as the source of the additional free cotinine at the higher storage temperatures. The results of this study are of much practical importance, since urine samples with free cotinine concentrations just below a cutoff value may become positive for smoking status if suitably low temperatures cannot be maintained during sample handling and shipment.

Usefulness of markers in managing tobacco withdrawal

To evaluate the usefulness of tobacco markers in dependent smokers being treated with transdermal nicotine patches, a study was conducted at the Tobacco Withdrawal Consultation Centre at the Hôpital Laennec, Paris, France. 125 patients were included in the study and, in a first time, carbon monoxide in exhaled air, carboxyhaemoglobin, urinary nicotine and cotinine, Fagerström index, were measured and correlated to the amount of nicotine inhaled per day. The most significant value was observed for cotinine. In a second time, 25 patients were followed clinically and biologically with urinary continine monitoring (group FC) and 73 were followed up only clinically (group FC). The success rate of therapy 12 weeks after the end of treatment was 72% in group FB and 28% in group FC. The nicotine patch dose was positively correlated (p < 0.01) with successful outcome. The lower the urinary cotinine level at 4 weeks, the more likely was successful outcome (p < 0.05). If psychological factors remain important, urinary cotinine monitoring in the course of nicotine patch treatment thus favours successful withdrawal.

The influence of cigarette consumption and smoking machine yields of tar and nicotine on the nicotine uptake and oral mucosal lesions in smokers

The purpose of this investigation, which has been performed as two studies, was to evaluate the association between the daily exposure to nicotine (measured as cigarette smoking machine yields) and the actual uptake of nicotine by cigarette smokers, as well as the association between oral mucosal changes and the exposure to cigarette smoke. In Study 1, consumption data, soft tissue changes and nicotine intake were measured in 47 habitual smokers using cigarettes with tar and nicotine yields within the ranges 9.3-12.2 and 0.72-1.16 mg per cigarette, respectively. The subjects were divided into three groups based on daily cigarette consumption; group averages (standard deviation) were 10.8 (2.2), 17.9 (1.9) and 28.4 (6.1) cigarettes per day. The group averages of tar deliveries from their usual brands of cigarettes were 11.1, 11.0 and 10.5 mg per cigarette, and group averages of nicotine deliveries were 1.05, 1.05 and 1.06 mg per cigarette, respectively. In Study 2, the same data were measured in a group of 77 habitual smokers with an average individual consumption of 11-21 cigarettes per day. The participants in Study 2 were divided into three groups according to tar delivery from their usual brands to cigarettes, with group averages of tar being 6.4 (1.2), 11.0 (1.2) and 16.0 (1.1) mg per cigarette, and of nicotine being 0.70 (0.12), 1.05 (0.12) and 1.34 (0.08) mg per cigarette, respectively. The average consumption of all three groups was within the range 17.1 to 17.9 cigarettes per day. The daily exposures to nicotine and tar were measured as the smoking machine yields multiplied by the number of cigarettes smoked per day. Nicotine uptake was determined by monitoring nicotine and its seven main metabolites in 24-h urine samples. In Study 1 there were significant differences between the three groups in the total amount of nicotine and metabolites excreted in the 24-h urine. The average nicotine uptake was 14.9, 24.4 and 35.4 mg per day, respectively. In Study 2, the 24-h excretion of nicotine and metabolites was about the same in all three groups and averaged 24.5 mg per day. The nicotine uptake was significantly correlated to the number of cigarettes smoked per day but not to the smoking machine yields of tar and nicotine per cigarette. The average prevalences for each of the different oral mucosal lesions (leukoedema, smoker's palate and hairy tongue) were found to increase with increasing consumption and nicotine uptake (Study 1); they were also independent of tar and nicotine yields from the cigarettes smoked (Study 2). These results indicate that the actual uptake of nicotine by smokers could not be estimated from the smoking machine yields. Reduction in exposure to smoke components may best be accomplished if smokers are encouraged to smoke fewer lower-yield cigarettes and to avoid smoking more of each cigarette.

A simple near-patient test for nicotine and its metabolites in urine to assess smoking habit

We describe a disposable, near-patient urine test to monitor cigarette smoking. A plastic device contains the sealed dried reagents to measure nicotine and its metabolites, by a colorimetric assay. The device can be used to give a qualitative assessment of tobacco consumption, simply by observing a colour change. Alternatively, the test can be quantified by measuring the light absorbance with a simple colorimeter, and a concentration of nicotinic metabolites obtained with reference to a cotinine standard. A correction factor for the concentration of the urine sample, based on light absorbance, allows the result to be expressed as a ratio to urine concentration. This method correlates with reported daily cigarette consumption (r = 0.69, p < 0.0001) and compares favourably with cotinine, as measured by gas chromatography (r = 0.89, p < 0.0001). The method provides a simple-to-use, inexpensive way to monitoring tobacco consumption in extralaboratory situations.

A study of the potential confounding effects of diet, caffeine, nicotine and lorazepam on the stability of plasma and urinary homovanillic acid levels in patients with schizophrenia

Ten men inpatients who met DSM-III-R criteria for schizophrenia participated. On five occasions at least one week apart, each subject had an intravenous line placed at 0730 after an overnight fast. On each occasion blood samples were drawn at 0800 and hourly thereafter through 1200 noon for measurement of plasma homovanillic acid (HVA). Total four-hour urine collections were obtained for measurement of urinary HVA. Subjects received five experimental conditions, in randomized sequence: no intervention, smoking one cigarette per hour, drinking one caffeinated cola per hour, lorazepam 2 mg IV push, or a high monoamine meal. Baseline (0800) plasma HVA measures showed only minor intrinsic variability. The average standard deviation in baseline plasma HVA over five occasions of measurement was low relative to the changes in HVA produced during treatment with antipsychotic medications. The high monoamine meal significantly elevated plasma HVA, with a similar trend for urinary HVA. Neither caffeine, nicotine, nor lorazepam significantly affected plasma or urinary HVA.

GC profiles of volatile constituents from human urine obtained by closed loop stripping, purge and trap technique and simultaneous stem distillation-extraction

Different techniques like "closed loop stripping" [CLSA], "purge and trap" [PTI], and continuous steam distillation extraction [SDE] were used to establish GC profiles of major histocompatibility complex-associated volatile constituents of human urine and statistically evaluated for reliability. Of the three methods investigated, PTI appeared to be superior for the detection of very volatile substances, whereas SDE was the most efficient one with respect to yield. A number of short to medium-chain ketones, 4-hydroxy-3-methoxy-styrene, menthol and nicotine were identified in preliminary analyses.

Human urine mutagenicity study comparing cigarettes which burn or primarily heat tobacco

Cigarette smokers have been reported to void urine which is more mutagenic, as measured in the Ames assay, than urine voided by non-smokers. Condensate from the mainstream smoke of a cigarette which primarily heats tobacco (test cigarette) has shown significantly reduced mutagenicity in a battery of in vitro genotoxicity assays compared with tobacco-burning cigarettes. The objective of this study was to determine whether the reduction in mutagenic activity observed in the in vitro assays would be reflected in the urine of smokers of the test cigarette. Twenty smokers were enrolled in a 4-week crossover study, with each smoker consuming test cigarettes ad libitum for a week and their usual brand of tobacco-burning cigarettes the other 3 weeks. Diet was strictly controlled throughout the study, and broiled and pan-fried meat was not served to minimize ingestion of mutagenic protein pyrolysis products. There was no statistically significant difference (p = 0.06) in consumption of tobacco-heating and tobacco-burning cigarettes. There were no statistically significant differences (p = 0.22) in salivary cotinine concentrations for smokers when smoking either tobacco-burning or tobacco-heating cigarettes. Urinary nicotine (ng/mg creatinine) was not different (p = 0.31) for smokers when smoking either tobacco-burning or tobacco-heating cigarettes. Urinary cotinine (ng/mg creatinine) was 32% lower (p = 0.0004) when smoking tobacco-heating cigarettes as compared with smoking tobacco-burning cigarettes. Twenty-four-hour urine samples were collected twice weekly, concentrated using XAD-2 resin and tested in Ames strains TA98 and YG1024 with metabolic activation. Tobacco-burning cigarette smokers experienced a 79% reduction in urinary mutagenicity as measured in strain YG1024 and a 72% reduction as measured in strain TA98 during the week that they smoked the tobacco-heating cigarette while maintaining a fixed dietary regimen. The results of this study indicate that smokers of tobacco-heating cigarettes void urine which is significantly less mutagenic than urine voided by smokers of tobacco-burning cigarettes.

Smoking during pregnancy: the dose dependence of birthweight deficits

OBJECTIVE

To assess whether a simple urine based estimate of relative daily nicotine intake could predict smoking related birthweight deficits more accurately than self-reported cigarette consumption.

DESIGN

Active smokers were identified by a simple qualitative colorimetric urine test procedure and their relative nicotine intakes assessed by determining the ratios of the urinary concentrations of nicotine plus its metabolites to creatinine using automated colorimetric methods.

SETTING

A large teaching hospital.

PARTICIPANTS

Three thousand and thirty-eight mothers from whom smoking histories had been elicited and who gave birth to live singleton babies after 28 weeks of gestation.

MAIN OUTCOME MEASURES

Birthweights (adjusted for maternal weight, maternal age, baby's sex, parity and length of gestation), maternal weight gains during pregnancy and placental weights.

RESULTS

The adjusted birthweight deficits of babies born to proven active smokers averaged 226 g (95% confidence interval 194 g to 258 g), but dose dependent effects were only apparent when nicotine intake was based on urinary nicotine metabolites/creatinine ratios. Among the smokers, adjusted birthweights fell linearly with increasing nicotine intakes but gave a predicted mean birthweight for nonsmokers that was 102 g (95% CI 50 g to 154 g) lighter than that actually found (P < 0.0001). Maternal weight gains during pregnancy were substantially reduced in smokers and correlated more closely with urinary nicotine metabolite excretions than with reported daily cigarette consumptions. Placental weights were unaffected by smoking.

CONCLUSION

There was a closer dose-effect relationship between birthweight deficits and urinary nicotine metabolites/creatinine ratios than with self-reported daily cigarette consumptions. The influence of nicotine exposure on birthweight appears to be biphasic, with one mechanism operating at very low levels of tobacco smoke intake and the other causing seemingly linearly related effects over the whole range of nicotine intakes of active smokers. These findings support recent evidence that passive smoking can cause substantial birthweight deficits.

Excretion of mutagens, nicotine and its metabolites in urine of cigarette smokers

Urine samples from 26 cigarette smokers on a restricted diet were collected in the late afternoon. Urine extracts on XAD-2 resin were tested for mutagenicity in the microsuspension assay using Salmonella typhimurium strain TA98 in the presence of metabolizing and deconjugating enzymes. Levels of urinary nicotine plus metabolites and cotinine were determined. Eighteen samples were clearly mutagenic, i.e. capable of doubling the number of spontaneous revertants at one of the assayed doses of urine. Urinary mutagenic activity ranged from 193 to 8462 net revertants/mmol of creatinine, while urinary nicotine plus metabolites and cotinine levels varied from 0.007 to 1.366 and from 0.011 to 0.297 mg/mmol creatinine. Urine samples with nicotine metabolite levels of < 0.33, 0.33- < 0.66 and > 0.66 mg/mmol creatinine had mean values +/- SD of mutagenic activity of 490 +/- 222 (n = 10), 964 +/- 560 (n = 9) and 2692 +/- 2807 (n = 7) revertants/mmol of creatinine, respectively, the statistical comparison between the groups being positive (Mann-Whitney U-test, P < 0.05). The mutagenic activity of urine samples from smokers correlated well with urinary nicotine plus metabolite levels (r = 0.658, P < 0.01). A less close correlation was found between urinary mutagenic activity and other indicators of tobacco smoke exposure, such as urinary cotinine (r = 0.504, P < 0.05), number of cigarettes smoked during the day of urine collection (r = 0.399, P < 0.05) and machine smoking-derived nicotine deliveries of the total number of cigarettes smoked (number of cigarettes multiplied by the nicotine content of each cigarette, as indicated by the manufacturer; r = 0.439, P < 0.05). These results suggest that the mutagenic activity of smokers' urine may be predicted by the urinary level of nicotine plus metabolites. The low degree of reliability of many presumptive indicators of exposure to tobacco smoke and the different urinary excretion kinetics of tobacco smoke mutagens with respect to cotinine (a frequently used biomarker for monitoring exposure to tobacco smoke) are both emphasized.

DNA adducts in urothelial cells: relationship with biomarkers of exposure to arylamines and polycyclic aromatic hydrocarbons from tobacco smoke

Markers of exposure to polycyclic aromatic hydrocarbons (urinary 1-hydroxypyrene-glucuronide) and aromatic amines (4-aminobiphenyl-hemoglobin adducts), as well as urinary mutagenicity, were measured in 47 healthy smokers and 50 nonsmokers. DNA adducts were determined by P32-postlabeling in the exfoliated bladder cells of 39 healthy subjects. Both 1-hydroxypyrene-glucuronide (1-OHPG) and 4-aminobiphenyl adducts (4-ABP-Hb) were associated with smoking habits, but only 4-ABP-Hb adducts were associated with consumption of black, air-cured tobacco. The levels of 2 DNA adducts (numbers 2 and 4) in urothelial cells were clearly associated with 4-ABP-Hb adducts, in all subjects and in smokers. Levels of one of these DNA adducts (number 2) were also associated with 1-hydroxypyrene-glucuronide in urines, but in smokers the association was not statistically significant. Overall, these observations constitute further evidence of a role of arylamines in tobacco-induced bladder cancer.

Comparison of measured and FTC-predicted nicotine uptake in smokers

Cigarette smokers have a wide variety of "tar" and nicotine yields to choose from in the current market, ranging from 0.5 mg "tar" and less than 0.05 mg nicotine to 27 mg "tar" and 1.8 mg nicotine by the Federal Trade Commission (FTC) method. To understand better the relationship between FTC nicotine yields and actual nicotine uptake in smokers, we have studied nicotine uptake in 33 smokers of self-selected products representing four "tar" groupings: 1 mg "tar" (1MG), ultra-low "tar" (ULT), full-flavor low "tar" (FFLT), and full flavor (FF) cigarettes. These cigarette categories had mean FTC nicotine yields of 0.14, 0.49, 0.67, and 1.13 mg/cigarette, respectively. The subjects smoked their usual brand of cigarette ad libitum and provided a 24-h urine sample for total nicotine uptake analysis over a period during which the number of cigarettes smoked was recorded. Nicotine uptake was determined by monitoring urinary nicotine and its metabolites, including the glucuronide conjugates. Daily nicotine uptake was 9.1 +/- 7.3 mg (range 1-21 mg) for 1MG, 19.2 +/- 10.0 mg (range 4-42 mg) for ULT, 21.8 +/- 9.4 mg (range 13-38 mg) for FFLT, and 37.1 +/- 14.4 mg (range 21-60 mg) for FF smokers. On a per cigarette basis, yields were 0.23 +/- 0.11, 0.56 +/- 0.23, 0.60 +/- 0.18, and 1.19 +/- 0.43 mg nicotine, respectively. Although individual variability was fairly large (CVs of 0.39-0.80), means for the different groups showed that lower FTC yield smokers not only absorb less nicotine per 24-h period, but also per cigarette smoked. These data suggest that nicotine uptake is a function of individual smoking behavior within product design limits. We conclude from these data that, while FTC yield cannot precisely predict nicotine uptake for an individual smoker, it is useful in predicting and comparing actual nicotine uptake by smokers who select cigarettes with a particular FTC yield.

[Tools for the assessment of tobacco dependence: comparison with questionnaires and marker assays]

Fagerström Tolerance Questionnaire has been questioned in some respects for the purpose of the evaluation of tobacco dependence. In a sample of 208 smokers attempting to quit, we measured on urinary samples the levels of nicotine metabolites via their thiobarbituric acid derivatives comparatively to the levels of nicotine and cotinine by high performance liquid chromatography. Urinary concentration of nicotine metabolites was 77.1 +/- 50.0 mumol/l. Nicotine and cotinine levels were respectively 8.2 +/- 12.0 mumol/l and 12.9 +/- 9.8 mumol/l. Spearman correlation coefficients were used to examine the relationships among various measures of exposure to cigarette smoke, tobacco markers and tobacco addiction scores obtained through the Fagerström Questionnaire and a Simplified Questionnaire. Nicotine metabolites are correlated with the score obtained with the Simplified Questionnaire (rho = 0.39) better than with the score of Fagerström (rho = 0.28) (p < 0.01). These moderate correlations suggest that the measurement of tobacco markers provide a more valuable information than questionnaires for the appreciation of the depth of tobacco intake. The questionnaires should not serve as a substitute for tobacco markers determination.

Smokers' behaviour and exposure according to cigarette yield and smoking experience

The influence of cigarette yield and length of smoking experience on smoking behaviour and biomarker levels was sought in 108 smokers who have never changed cigarette class. Smoking parameters carboxyhaemoglobin percentage (COHb), urinary nicotine, and its metabolites, mutagens, and thioethers were measured. Cigarette yield does not affect daily consumption or smoke volume puffed per cigarette. But the inhalation depth increases with decreasing cigarette yield and with length of smoking habit. The COHb level after the first cigarette in the morning increases significantly with CO cigarette yield and length of smoking experience. In the evening, only the cigarette yield has an effect on COHb level. Biomarker levels excreted in urine are generally lower for females than for males. They tend to increase with smoking history. Only COHb level and total urinary nicotine metabolites (Barlow index) are weakly correlated with cigarette yield. The absence of significant differences due to cigarette class in urinary biomarkers can be explained by changes in inhalation depth, individual differences of metabolism, and limited specificity of some markers (mutagens, thioethers).

Urinary nicotine metabolite excretion and lung cancer risk in a female cohort

A nested lung cancer case-control study was carried out using 397 12 h urine samples originally collected from a cohort of over 26,000 women aged 40-64 at entry who were then followed for up to 15 years. The urine samples from active smokers were first identified using a simple qualitative method and their total nicotine metabolites/creatinine ratios then determined by automated colorimetric methods. The results obtained demonstrated the capacity of nicotine metabolite estimations in a single 12 h sample of urine to predict the subsequent risk of lung cancer. The risk of lung cancer among the biochemically proven active smokers during this period was 7.8 times that of the non-smokers, suggesting that the dose-response relationship between smoking and lung cancer is no less step in women than in men. The smoking-related risk of adenocarcinoma was less than that of other lung carcinomas. It is suggested that this biochemical epidemiology approach to exploring the relationship between smoking and lung cancer could profitably be applied to the study of other smoking-related diseases.

In vitro-in vivo correlations of human (S)-nicotine metabolism

The profile of (S)-nicotine metabolism in human liver microsomes was examined at concentrations approaching in vivo conditions (10 microM). At such concentrations, no (S)-nicotine N-1'-oxygenation was seen, and thus C-oxidation to the (S)-nicotine delta 1',5'-iminium ion was the sole product observed in the metabolic profile in the presence of the human liver microsomes. For simplicity of analysis, the (S)-nicotine delta 1',5'-iminium ion formed was converted to (S)-cotinine in the presence of exogenously added aldehyde oxidase. To explain the lack of (S)-nicotine N-1'-oxygenation at low (S)-nicotine concentrations, inhibition of flavin-containing monooxygenase (FMO) activity by (S)-cotinine was examined. Although (S)-cotinine was observed to inhibit pig FMO1 (Ki = 675 microM), partially purified cDNA-expressed adult human liver FMO3 was not inhibited by (S)-cotinine. We therefore concluded that the kinetic properties of the nicotine N'- and C-oxidases were responsible for the metabolic product profile observed. Kinetic constants were determined for individual human liver microsomal preparations from low (10 microM) and high (500 microM) (S)-nicotine concentrations by monitoring (S)-cotinine formation with HPLC. The mean Kmapp and Vmax for formation of (S)-cotinine by the microsomes examined were 39.6 microM and 444.3 pmol.min-1.(mg protein)-1, respectively. The formation of (S)-cotinine was strongly dependent on the previous drug administration history of each subject, and among the highest rates for (S)-cotinine formation were those of the barbiturate-pretreated subjects. The rate of (S)-cotinine formation at low (10 microM) concentration correlated well with immunoreactivity for cytochrome P450 2A6 (r = 0.89). In vitro-in vivo correlation of the results suggests that the low amount of (S)-nicotine N-1'-oxygenation and the large amount of (S)-cotinine formed in human smokers (i.e. 4 and 30% of a typical dose, respectively) are determined primarily by the kinetic properties of the human monooxygenase enzyme systems. However, additional non-hepatic monooxygenase(s) contributes to (S)-nicotine metabolism.

Reduction in nicotine intake and oral mucosal changes among users of Swedish oral moist snuff after switching to a low-nicotine product

The purpose of this investigation was to assess nicotine regulation among users of portion-bag Swedish oral moist snuff (snus) when switching from an ordinary snus product (Brand A) to a low-nicotine product having only half the concentration of nicotine (Brand B). Two studies were performed to compare the short-term effects on consumption and nicotine intake of switching to low-nicotine snus with those of long-term effects. In Study 1, consumption data, soft tissue changes and nicotine intake were measured in a group of 24 habitual users of Swedish portion-bag snus, both during use of their ordinary snus (Brand A) for 2 weeks and during consumption of the low-nicotine product (Brand B) for 10 weeks. In study 2, the same data were measured during 2 weeks in a reference group of 18 snus users who had been habitual users of the low-nicotine snus (Brand B) for at least one year. Although there was no increase in number of hours of daily consumption, the amount of snus consumed increased on average by 2 grams a day (+15%) when switching from Brand A to the low-nicotine Brand B (Study 1). The Brand B reference group (Study 2) consumed about 3 grams less snus a day during the same number of hours as the subjects in Study 1 who had switched to Brand B. These results indicate that snus users compensate to a small extent for the lower nicotine delivery by increasing their consumption on short-term switching but the same does not apply to long-term users.(ABSTRACT TRUNCATED AT 250 WORDS)

Solid-phase extraction of nicotine and its metabolites for high-performance liquid chromatographic determination in urine

A solid-phase extraction, using Extrelut-1 glass columns, has been applied to urine samples of both passive and active smokers for high-performance liquid chromatographic determination of nicotine and its metabolites cotinine and trans-3'-hydroxycotinine. Chromatography was performed using a reversed-phase LC8DB column and a mobile phase consisting of water-acetonitrile (80:9, v/v) containing 5 ml triethylamine, 670 mg/l sodium heptanesulphonate, and 0.034 M each of K2HPO4 and citric acid (pH 4.4), at a flow-rate of 1.6 ml/min. The results obtained indicate that solid-phase extraction is a reliable and quick procedure which can be applied also to other nicotine metabolites.

Measurement of markers of tobacco smoking in patients with coronary heart disease

591 patients with a history of coronary heart disease had one or more biochemical markers of tobacco smoking measured. 26% were self reported smokers and a further 4% were apparent 'smoking deceivers'. The urinary nicotine metabolite concentration is an excellent marker for tobacco smoking; breath CO would be a suitable alternative for busy clinics. Half the patients were subjected to regular advice on risk factor management but there was no evidence that this contributed effectively to smoking cessation. Overall smoking cessation rate was poor.

Nicotine and cotinine accumulation in pigmented and unpigmented rat hair

This study was performed to assess the contribution of systemic and external uptake to nicotine accumulation in hair. The systemic nicotine uptake in hair was determined in pigmented rats (Brown Norway) and albino rats (Sprague-Dawley) after subcutaneous administration of 3 doses of nicotine with osmotic minipumps [5, 10, and 20 mg/(kg x day) for 3 weeks], the highest dose also following metabolic enzyme induction. The external nicotine uptake was determined in cut hair of both strains after exposure to room-aged cigarette sidestream smoke, a surrogate for environmental tobacco smoke (nicotine concentration: 5 micrograms/liter for 1, 2, and 3 weeks). Nicotine and its metabolite cotinine were determined using capillary GC after complete alkaline digestion of the hair sample and solvent extraction. Systemic uptake: Nicotine and cotinine concentrations in hair were dose-dependent and correlated with plasma concentrations. The nicotine concentration was approximately 20 times higher in pigmented than in unpigmented hair. The cotinine concentration was approximately 10 times lower than the nicotine concentration in pigmented hair. After enzyme induction before administration, nicotine and cotinine concentrations in hair were significantly reduced in parallel to the reduced plasma concentrations, showing the influence of metabolism. External uptake: Nicotine was found in the hair of both strains, the concentration in pigmented hair being a factor of 1.5 higher than in unpigmented hair. Thus, hair pigmentation had a major influence on systemic uptake in hair and a minor influence on external uptake in hair.(ABSTRACT TRUNCATED AT 250 WORDS)