The bioequivalent and effect of nicotine formulation gum on smoking cessation

OBJECTIVE

To compare the absorption rate of nicotine in volunteer blood, and determine the clinical trial on smoking cessation.

MATERIAL AND METHOD

This method using reverse phase C18 column and buffer pH 5.05 as the mobile phase, flow rate 0.9 ml/min. The UV-visible detector found the retention time of nicotine in gum and volunteer blood was 5.0756 min. The linear calibration curves of nicotine in human blood were obtained over the concentration range of 2.0-20.0 microg/ml. The coefficient variability for Nicotine gum 6.74% (2 mg/g). Extraction recovery was over 86% in blood, correlation coefficient of determination (r2) > 0.9999 and the detection limit 0.0060 microg/ml. The 24 healthy volunteer men, 27 to 55 years of age, were habitual cigarette smokers. They were randomized into two groups, 12 subjects chewed two 2 mg pieces, Nicomild-2 Sugar Free Gum (Millimed, Thailand), the other chewed two 2 mg, pieces, Nicorette Sugar Free (Pharmacia AB, Helsingborg, Sweden.) Volunteers' blood samples were withdrawn at 0, 15, 30, 40 min, concentration of nicotine in blood were measured by HPLC. The 199 subjects were openly recruited under the project of "The smoking cessation for Phor Laung" (5-December). All of them received Nicomild-2 (nicotine polyestex gum) between November 2007 and December 2007.

RESULTS

The absorption rate of nicotine in volunteers' blood Nicomild-2 and Nicorette at 0, 15, 30, 40 minutes were 0, 51.84, 26.73, 21.012 and 0, 56.603, 21.83, 15.183 (ng/min). Both of them were found to have maximum absorption rate at 15 minutes. When comparing the maximum absorption rate at 15 minute of Nicomild-2 (sugar free) with Nicorette (sugar free) didn't have significant differences detected. Treatment with nicotine polyestex gum were reported 65.3% (130/199) at 4 weeks compared with failure 30.15% (60/199)[ 65.3% vs 30.15%; p = 0.005]. The authors found 9 (4.5%) subjects successfully quit smoking free nicotine replacement therapy (NRT).

Extinction with varenicline and nornicotine, but not ABT-418, weakens conditioned responding evoked by the interoceptive stimulus effects of nicotine

The interoceptive stimulus effects of nicotine acquire control over behavior. This observation, among others, suggests that the stimulus effects of nicotine are important in the development and tenacity of tobacco dependence. Despite this importance, there has been little research examining whether non-reinforced presentations (extinction) of a ligand that share stimulus effects of nicotine will weaken responding controlled by nicotine. Rats were trained to discriminate nicotine (0.4 mg/kg) from saline using a discriminated goal-tracking task in which nicotine signaled intermittent access to sucrose; sucrose was withheld on saline sessions. Experiment 1 examined substitution for nicotine by ABT-418, nornicotine, epibatidine, varenicline, or cytisine in 4-min extinction tests. Experiments 2-5 [low-dose nicotine (0.05 mg/kg), ABT-418, nornicotine, or varenicline, respectively] examined whether substitution for nicotine would persist if extinction tests were increased to 20 min and repeated daily for 6 days. Finally, generalization of this extinction back to the nicotine training stimulus was assessed. Full substitution in brief 4-min extinction tests was seen for ABT-418, nornicotine, epibatidine, varenicline, and cytisine. Low-dose nicotine, ABT-418, nornicotine, and varenicline, evoked only a partial 'nicotine-like' response in the first 20-min extinction test. With repeated extinction, only low-dose nicotine, nornicotine, and varenicline continued to substitute. Extinction with nornicotine and varenicline transferred back to nicotine as indicated by a partial conditioned response to the training stimulus. Interpretations regarding 'nicotine-like' effects of a ligand depend on the nature of the test. Understanding the processes mediating transfer of extinction learning with potential pharmacotherapies may reveal new treatment targets.

Metabolism of nicotine in rat lung microvascular endothelial cells

The aim of this study was to examine whether cultured rat lung microvascular endothelial cells (LMECs), which constitute the gas-blood barrier, have the ability to metabolize nicotine. Nicotine was biotransformed to cotinine and nicotine N′-oxide by cytochrome 450 (CYP) and flavin-containing monooxyganase (FMO), respectively, in rat LMECs. The intrinsic clearance (Vmax1/Km1) for the cotinine formation was about 20 times as high as that for the trans-nicotine N′-oxide formation in the low-Km phase, indicating that oxidation by CYP was much higher than that by FMO. On the other hand, as shown in Eadie-Hofstee plots, the formation of cis-nicotine N′-oxide was monophasic, whereas the plot for the trans-nicotine N′-oxide formation was clearly biphasic. These results suggest that nicotine N′-oxide was stereoselectively metabolized to cis and trans forms. However, in the high-Km phase there was no significant difference in N′-oxidation between the cis and trans forms. Moreover, we suggest that CYP2C11 and CYP3A2 are key players in the metabolism to cotinine of nicotine in rat LMECs using the respective enzyme inhibitors (tranylcypromine and troleandomycine). On the other hand, methimazole (5 μm) caused 73 and 45% decreases in the formation of N′-oxides of cis- and trans- enantiomers, respectively, demonstrating the presence of FMO in rat LMECs. These results suggest that rat LMEC enzymes can convert substrates of exogenous origin such as nicotine for detoxication, indicating LMECs are an important barrier for metabolic products, besides hepatic cells.

Effect of tobacco counseling by dental students on patient quitting rate

Tobacco use has widespread, devastating effects on the body, including the oral cavity. Today's dental professional must be trained to counsel patients on tobacco cessation, but dental health professionals and students do not feel confident in their counseling abilities. The University at Buffalo School of Dental Medicine (SDM) established the Tobacco Counseling Cessation Protocol (TCCP), which was implemented in the dental curriculum, and dental students were trained in its use. The goal of this project was to assess the effectiveness of the TCCP by surveying both patients and dental students. Students and patients were contacted to determine the effect of the TCCP on the quitting rate. Third- and fourth-year dental students were surveyed through the school e-mail system and asked to report on their tobacco cessation counseling practices. Patients who received TCCP received follow-up telephone calls to obtain their input on the program and also to determine if they had quit. According to the follow-up survey, 14 percent of patients reduced the number of cigarettes smoked per day, and 22 percent quit entirely. Fifty-one percent of those who received the TCCP made a commitment to quit at the time of the intervention; 32 percent of those receiving the TCCP were still smoke-free at six months, but 19 percent had returned to smoking. If predoctoral students receive appropriate training, they can be effective in motivating patients to quit smoking. Dental students are generally receptive to the educational material on tobacco use and smoking cessation counseling, yet only half report routinely implementing the TCCP. More needs to be done to incorporate tobacco cessation counseling into routine dental care. The culture of dentistry must be changed to view tobacco use as a dental problem.

Nicotine replacement therapy use among adolescent smokers seeking cessation treatment

OBJECTIVE

To examine the correlates of prior nicotine replacement therapy (NRT) in an urban sample of adolescent smokers seeking smoking cessation treatment.

DESIGN

Adolescents were recruited via radio, TV and print advertisements for participation in treatment studies. Participants completed a structured interview usinga prescreeningquestionnaire.

SETTING

Data were collected via a telephone interview by trained research personnel.

PARTICIPANTS

A sample (N=1879) cessation treatment-seeking volunteer boys (38.2%) and girls (61.8%) aged 12 to 17 years, from a diverse ethnic background residing in the Baltimore, Maryland metropolitan area.

INTERVENTIONS

No interventions were used in this observational study.

MAIN OUTCOME MEASURES

Use of NRT in adolescents stratified by age, Fagerstrom Test of Nicotine Dependence (FTND), and race/ethnicity.

RESULTS

The sample had a mean FTND score of 5.7 (SD = 2.2). About 41% smoked 11 to 20 cigarettes per day. Adolescent smokers who had used NRT were statistically but only marginally older than those who had not (15.9 vs 15.7 years; t-test= -2.60, P=0.01). FTND score, a measure of nicotine dependence, was higher among those who had used NRT (6.0 vs 5.6; t-test= -3.37, P= .001). African American adolescents were less likely to have used NRT than their European American counterparts (33.0% vs 61.2%; chi2=16.09, P<.003). After stepwise logistic regression analyses, age, FTND and race/ethnicity remained predictors of NRT use.

CONCLUSION

Our results show differences in NRT use patterns based on age, FTND, and race/ethnicity. European American youths are more likely than their 'other' counterparts to use NRT, after adjusting for age and smoking severity, whereas, African American youth are less likely than their 'other' counterparts to use NRT. These findings suggest racial/ethnic disparities in accessing smoking cessation modalities among adolescents. Further research is needed to fully elucidate factors contributing to these differences in order to facilitate increased smoking cessation rates among all adolescents.

A randomized clinical trial of nicotine lozenge for smokeless tobacco use

INTRODUCTION

Smokeless tobacco (ST) use is associated with adverse health consequences, and effective treatments are needed. Pilot data suggest that 4-mg nicotine lozenge decreases tobacco craving and nicotine withdrawal symptoms among ST users.

METHODS

We conducted a randomized, placebo-controlled multicenter clinical trial to evaluate the efficacy of 12 weeks of 4-mg nicotine lozenge for ST use.

RESULTS

We randomized 270 participants (136 active lozenge, 134 placebo). No significant differences were observed between the groups in biochemically confirmed all tobacco abstinence rates at Week 12 (36% lozenge vs. 27.6% placebo; odds ratio [OR] 1.5, 95% CI 0.7-2.1; p = .138). However, the 4-mg nicotine lozenge increased self-reported all tobacco abstinence (44.1% vs. 29.1%; OR 1.9, 95% CI 1.2-3.2; p = .011) and self-reported ST abstinence (50.7% vs. 34.3%; OR 2.0, 95% CI 1.2-3.2; p = .013) compared with placebo at the end of treatment (Week 12). Following target quit date (TQD), nicotine withdrawal symptoms decreased significantly with time (time effect = -.022 per day, SE = .003; p < .001) and was significantly lower for the active lozenge (treatment effect = -.213, SE = .071; p = .003). Tobacco craving also decreased significantly following TQD (time effect = -.071, SE = .006; p < .001) and was lower for the active nicotine lozenge (treatment effect = -.452, SE = .164; p = .006).

DISCUSSION

The 4-mg nicotine lozenge increased self-reported but not biochemically confirmed tobacco abstinence rates at 3 months. The use of the 4-mg nicotine lozenge is associated with decreased nicotine withdrawal symptoms and tobacco craving.

Computational neural network analysis of the affinity of N-n-alkylnicotinium salts for the alpha4beta2* nicotinic acetylcholine receptor

Based on an 85 molecule database, linear regression with different size datasets and an artificial neural network approach have been used to build mathematical relationships to fit experimentally obtained affinity values (K(i)) of a series of mono- and bis-quaternary ammonium salts from [(3)H]nicotine binding assays using rat striatal membrane preparations. The fitted results were then used to analyze the pattern among the experimental K(i) values of a set of N-n-alkylnicotinium analogs with increasing n-alkyl chain length from 1 to 20 carbons. The affinity of these N-n-alkylnicotinium compounds was shown to parabolically vary with increasing numbers of carbon atoms in the n-alkyl chain, with a local minimum for the C(4) (n-butyl) analogue. A decrease in K(i) value between C(12) and C(13) was also observed. The statistical results for the best neural network fit of the 85 experimental K(i) values are r(2) = 0.84, rmsd = 0.39; r(cv)(2) = 0.68, and loormsd = 0.56. The generated neural network model with the 85 molecule training set may also be of value for future predictions of K(i) values for new virtual compounds, which can then be identified, subsequently synthesized, and tested experimentally.

[Development of analytical method for determination nicotine metabolites in urine]

The assay of biomarkers in biological material is the most popular and reliable method in estimate exposure to tobacco smoke. Nicotine and its metabolites qualify to the most specific biomarkers for tobacco smoke. Currently the most often used are cotinine and trans-3'-hydroxycotinine. The aim of this study was development of easy and quick method of determining nicotine and its main metabolites with high performance liquid chromatography--available in most laboratories. Nicotine and its metabolites in urine (cotinine, trans-3'-hydroxycotinine, nornicotine and nicotine N-oxide) was determined by means of high performance liquid chromatography with spectrometry detection (HPLC-UV). The determined compounds were extracted from urine by means of the liquid-liquid technique, before analysed by the HPLC method. Developed technique of high performance liquid chromatography proved to be useful to assessment nicotine and its four metabolites in smokers, though further research are necessary. The further modification of procedure is required, because of the interferences of cotinine N-oxide with matrix, which prevent determination. Increasing the efficiency of extraction nicotine and nornicotine could enable the determination in people exposed on environmental tobacco smoke (ETS). This study confirm other authors' observations that 3'-hydroxycotinine might be equivalent with cotinine predictor of tobacco smoke exposure, however further studies are required.

Enantioseparation of nicotine alkaloids in cigarettes by CE using sulfated beta-CD as a chiral selector and a capillary coated with amino groups

Nicotine (NC) and its related compounds (cotinine (CN), nornicotine (NN), anatabine (AT) and anabasine (AB)) were simultaneously enantioseparated by CE using a capillary with amino groups and sulfated beta-CD as a chiral selector. The optimum running conditions were found to be 30 mM acetate buffer (pH 5.0) containing 8% sulfated beta-CD with an applied voltage of +15 kV at 30 degrees C using direct detection at 260 nm. Using a capillary coated with amino groups, the EOF migrates toward the positive pole. However, when sulfated beta-CD was added to the BGE, it was found that the EOF migrated toward the negative pole due to ionic adsorption of sulfated beta-CD to amino groups on the capillary inner wall. All the cationic analytes migrated as anions, suggesting that they formed stable anionic complexes with sulfated beta-CD. With this system and a simple pretreatment with mini-cartridges, NC alkaloids in five cigarette samples were enantioseparated. As a result, each of the compounds except for CN was detected. In the case of NC, only (S)-NC was detected (more than 99.9%), but in the case of NN, AT and AB, the ratios of (S)-isomer to total isomers were in the ranges 58-70, 81-85 and 59-65%, respectively. On the other hand, only NC was detected in cigarette smoke and the ratio of (S)- and (R)-NCs was 96:4. The amounts of NC alkaloids in cigarettes suggest that the production of (R)-NC resulted from racemization due to the high temperature/burning of the cigarette.

Meconium nicotine and metabolites by liquid chromatography-tandem mass spectrometry: differentiation of passive and nonexposure and correlation with neonatal outcome measures

BACKGROUND

Meconium analysis is a diagnostically sensitive and objective alternative to maternal self-report for detecting prenatal tobacco exposure. Nicotine and metabolite disposition in meconium is poorly characterized, and correlation of analytes' concentrations with neonatal outcomes is unexplored. Our objectives were to quantify nicotine, cotinine, trans-3'-hydroxycotinine (OH-cotinine), nornicotine, norcotinine, and glucuronide concentrations in meconium, identify the best biomarkers of in utero tobacco exposure, compare meconium concentrations of tobacco-exposed and nonexposed neonates, and investigate concentration-outcome relationships.

METHODS

We quantified concentrations of nicotine and 4 metabolites with and without hydrolysis simultaneously in meconium from tobacco-exposed and nonexposed neonates by liquid chromatography-tandem mass spectrometry. We compared meconium concentrations to birth weight, length, head circumference, gestational age, and 1- and 5-min Apgar scores.

RESULTS

Nicotine, cotinine, and OH-cotinine were the most prevalent and abundant meconium tobacco biomarkers and were found in higher concentrations in tobacco-exposed neonates. Whereas cotinine and OH-cotinine are glucuronide bound, performing the lengthy and costly enzymatic hydrolysis identified only 1 additional positive specimen. Unconjugated nicotine, cotinine, or OH-cotinine meconium concentration >10 ng/g most accurately discriminated active from passive and nonexposed neonates. There was no significant correlation between quantitative nicotine and metabolite meconium results and neonatal outcomes, although presence of a nicotine biomarker predicted decreased head circumference.

CONCLUSIONS

Unconjugated nicotine, cotinine, and OH-cotinine should be analyzed in meconium to detect in utero tobacco exposure, as approximately 25% of positive specimens did not contain cotinine. Immunoassay testing monitoring cotinine only would underestimate the prevalence of prenatal tobacco exposure.

Predictors of early abstinence in smokers with schizophrenia

BACKGROUND

In patients with schizophrenia, the smoking cessation rate is low and the burden of smoking-related morbidity and mortality is high. Identification of factors associated with abstinence may allow clinicians to optimize treatment prior to a smoking cessation attempt.

METHOD

To identify factors associated with successful smoking cessation in patients with a DSM-IV diagnosis of schizophrenia, we analyzed baseline data from 114 stable outpatient smokers with schizophrenia who participated in 1 of 2 smoking cessation trials. The outcome of interest was 4 weeks' continuous abstinence at the end of a 12-week nicotine dependence treatment intervention. Baseline factors associated with abstinence were identified with univariate methods and entered into a manual, forward-selection multivariable regression model to identify independent predictors of abstinence. The study was conducted from March 1999 to February 2004.

RESULTS

Fourteen of 114 participants (12%) had biochemically verified 4 weeks' continuous abstinence at week 12. We included 10 noncorrelated variables with a univariate association with abstinence in a multivariable model, controlling for pharmacotherapy, age, and gender. Age at initiation of smoking and baseline variability in attentiveness, as measured by Continuous Performance Test-AX (CPT-AX) hit reaction time standard error, were independently associated with abstinence. For every year increase in age at initiation of smoking, the OR for abstinence was 1.36 (95% CI = 1.01 to 1.83), p = .048. For every millisecond decrease in the variability of the reaction time of CPT-AX, the OR for achieving abstinence was 1.55 (95% CI = 1.07 to 2.24), p = .021.

CONCLUSION

Later initiation of smoking was associated with increased and baseline attentional impairment with reduced odds of abstinence. Additional research to further our understanding of the relationship between attentional impairment and cigarette smoking in schizophrenia may lead to improved nicotine dependence treatments for this group.

Identification of adducts formed in the reactions of 5'-acetoxy-N'-nitrosonornicotine with deoxyadenosine, thymidine, and DNA

N'-Nitrosonornicotine (NNN) is the most prevalent of the carcinogenic tobacco-specific nitrosamines found in all tobacco products. Previous studies have demonstrated that cytochrome P450-mediated 5'-hydroxylation of NNN is a major metabolic pathway leading to mutagenic products, but to date, DNA adducts formed by this pathway have been only partially characterized, and there have been no studies reported on adducts formed with bases other than dGuo. Because adducts with dAdo and dThd have been identified in the DNA of the livers of rats treated with the structurally related carcinogen N-nitrosopyrrolidine, we investigated dAdo and dThd adduct formation from 5'-acetoxyNNN (3), a stable precursor to 5'-hydroxyNNN (2). Reaction of 3 with dAdo gave diastereomeric products, which were identified by their spectral properties and LC-ESI-MS/MS-SRM analysis as N(6)-[5-(3-pyridyl)tetrahydrofuran-2-yl]dAdo (9). This adduct was further characterized by NaBH(3)CN reduction to N(6)-[4-hydroxy-4-(3-pyridyl)but-1-yl]dAdo (17). A second dAdo adduct was identified, after NaBH(3)CN treatment, as 6-[2-(3-pyridyl)pyrrolidin-1-yl]purine-2'-deoxyriboside (18). Reaction of 3 with dThd, followed by NaBH(3)CN reduction, gave O(2)-[4-(3-pyridyl)-4-hydroxybut-1-yl]thymidine (11). Adducts 9, 11, 17, and 18 were all identified by LC-ESI-MS/MS-SRM comparison to synthetic standards. The reaction of 3 with calf thymus DNA was then investigated. The DNA was enzymatically hydrolyzed to deoxyribonucleosides, and the resulting mixture was treated with NaBH(3)CN and analyzed by LC-ESI-MS/MS-SRM. Adducts 11, 17, and 18, as well as the previously identified dGuo adducts, were identified. The results of this study provide a more comprehensive picture of DNA adduct formation by the quantitatively important 5'-hydroxylation pathway of NNN and will facilitate investigation of the presence of these adducts in laboratory animals treated with NNN or in people who use tobacco products.

Smoking and Parkinson's disease: does nicotine affect alpha-synuclein fibrillation?

alpha-synuclein is a small presynaptic protein (14,460 D) that is abundantly distributed in the brain. Although, its function is unknown, the aggregated form of alpha-synuclein is a pathological hallmark of several neurodegenerative diseases, including Parkinson's disease (PD). Epidemiological studies have shown that smoking can lessen the incidence of Parkinson's disease, indicating that smoke may contain chemicals that are neuro-protective. The fibrillation of alpha-synuclein was studied in relation to five different compounds found in cigarette smoke: anabasine, cotinine, hydroquinone, nicotine and nornicotine. Thioflavin T assays, gel electrophoresis, size exclusion chromatography-high performance liquid chromatography (SEC-HPLC) and atomic force microscopy (AFM) were utilized to monitor the rate of alpha-synuclein fibrillation and the inhibitory effects of the cigarette smoke components. We show that nicotine and hydroquinone inhibit alpha-synuclein fibril formation in a concentration-dependent manner, with nicotine being more effective. The SEC-HPLC data show that nicotine and hydroquinone stabilize soluble oligomers. The morphology of the oligomers stabilized by nicotine was evaluated by AFM, which showed the presence of three stable oligomers with an average height of 16 nm, 10 nm and 4 nm. Comparable results were obtained for the effect of the cigarette smoke components on the A53T mutant fibrillation. These results show that nicotine and hydroquinone inhibit alpha-synuclein fibrillation and stabilize soluble oligomeric forms. This information can be used to understand the molecular mechanism of the nicotine and hydroquinone action to develop therapeutic solutions for PD.

Nicotine derivatives in wastewater and surface waters: application as chemical markers for domestic wastewater

Nicotine is extensively metabolized in the human body to a number of compounds, which may enter natural waters via discharge of domestic wastewater. However, little is known on exposure of and potential effects on the aquatic environment. In this study, two major urinary metabolites, cotinine and 3'-hydroxycotinine, as well as a further tobacco alkaloid, N-formylnornicotine, were measured in wastewater and water from Swiss lakes using an analytical procedure based on SPE and LC-MS/MS SRM with cotinine-d3 as internal standard (LOQs, 1.0-1.5 ng/L). Typical concentrations of cotinine and 3'-hydroxycotinine were approximately 1-10 microg/L in untreated wastewater, but clearly less in treated wastewater (approximately 0.01-0.6 microg/L), corresponding to elimination efficiencies of 90-99%. N-Formylnornicotine, however,was found at similar concentrations in untreated and treated wastewater (0.02-0.15 microg/L). Its apparent persistence during wastewater treatment was further confirmed by incubation experiments with activated sludge. In lakes, cotinine, 3'-hydroxycotinine, and N-formylnornicotine were detected at concentrations up to 15, 80, and 6 ng/L, respectively. Concentrations in lakes correlated with the expected anthropogenic burden by domestic wastewater (ratio population per water throughflow), demonstrating the suitability of these nicotine derivatives as hydrophilic, anthropogenic markers. In small receiving waters with significant wastewater discharges, concentrations of a few hundred ng/L may be expected. Possible ecotoxicological risks associated with such environmental concentrations, can, however, not be assessed at present as data on effects on aquatic organisms are very limited, in particular on long-term effects.

Highly enantioselective borane reduction of heteroaryl and heterocyclic ketoxime ethers catalyzed by novel spiroborate ester derived from diphenylvalinol: application to the synthesis of nicotine analogues

An asymmetric synthesis for the preparation of nonracemic amines bearing heterocyclic and heteroaromatic rings is described. A variety of important enantiopure thionyl and arylalkyl primary amines were afforded by the borane-mediated enantioselective reduction of O-benzyl ketoximes using 10% of catalyst 10 derived from ( S)-diphenylvalinol and ethylene glycol with excellent enantioselectivity, in up to 99% ee. The optimal condition for the first asymmetric reduction of 3- and 4-pyridyl-derived O-benzyl ketoxime ethers was achieved using 30% of catalytic loading in dioxane at 10 degrees C. ( S)- N-ethylnornicotine ( 3) was also successfully synthesized from the TIPS-protected ( S)-2-amino-2-pyridylethanol in 97% ee.

Enantiomeric analysis of anatabine, nornicotine and anabasine in commercial tobacco by multi-dimensional gas chromatography and mass spectrometry

A fully automated multi-dimensional gas chromatography (MDGC) system with a megabore precolumn and cyclodextrin-based analytical column was developed to analyze the enantiomeric compositions of anatabine, nornicotine and anabasine in commercial tobacco. The enantiomer abundances of anatabine and nornicotine varied among different tobacco. S-(-)-anatabine, as a proportion of total anatabine, was 86.6% for flue-cured, 86.0% for burley and 77.5% for oriental tobacco. S-(-)-nornicotine, as a proportion of total nornicotine, was 90.8% in oriental tobacco and higher than in burley (69.4%) and flue-cured (58.7%) tobacco. S-(-)-anabasine, as a proportion of total anabasine, was relatively constant for flue-cured (60.1%), burley (65.1%) and oriental (61.7%) tobacco. A simple solvent extraction with dichloromethane followed by derivatisation with trifluoroacetic anhydride gave relative standard deviations of less than 1.5% for the determination of the S-(-)-isomers of all three alkaloids. The study also indicated that, a higher proportion of S-(-)-nornicotine is related to the more active nicotine demethylation in the leaf.

Treatment of tobacco dependence

Cigarette smoking continues to cause substantial death and disability, but more than 1 in 5 adults smoke despite the desire among most smokers to stop and the availability of effective treatments. A systematic process to identify all smokers is crucial. Because tobacco dependence is characterized by relapses and remissions, clinicians should be ready to engage smokers and reengage relapsed smokers with options for new medication strategies and additional counseling resources.

Cost-effectiveness of varenicline compared with bupropion, NRT, and nortriptyline for smoking cessation in the Netherlands

OBJECTIVE

To examine the cost-effectiveness of varenicline, a new pharmacotherapy to support smoking cessation, compared with the currently available pharmacologic alternatives in the Netherlands.

METHODS

The BENESCO-model was used to estimate the long-term health and economic benefits of smoking cessation for a cohort of smokers making a one-time quit attempt. The cohort represented the population of Dutch smokers with respect to gender, age, and prevalence of the smoking-related diseases included in the model: COPD, lung cancer, CHD, stroke, and asthma exacerbations. The model compared the cumulative incidence of smoking-related diseases, (quality-adjusted) life years, intervention costs, and direct medical costs between the cohort treated with varenicline and the same cohort either untreated (unaided cessation) or treated with bupropion, nortriptyline or NRT. The time horizon was lifetime. Future costs were discounted at 4%, health outcomes at 1.5%.

RESULTS

The cost of varenicline per additional quitter ranged from 1030 Euro compared with NRT to 4270 Euro compared with nortriptyline. When including the savings due to the reduction in incidence of smoking-related diseases, varenicline generated net savings compared with bupropion and NRT. Compared with nortriptyline and unaided cessation, varenicline was estimated to cost 1650 Euro/QALY and 320 Euro/QALY gained, respectively. At a willingness-to-pay as low as 5000/QALY gained, the probability that varenicline was cost-effective was more than 80% compared to bupropion, NRT, and unaided cessation and about 60% compared to nortriptyline.

CONCLUSION

Treatment with varenicline for smoking cessation is cost-effective compared with nortriptyline and unaided cessation and even cost-saving compared with bupropion and NRT.

Identification of novel CYP2A6*1B variants: the CYP2A6*1B allele is associated with faster in vivo nicotine metabolism

Cytochrome P450 2A6 (CYP2A6) is the human enzyme responsible for the majority of nicotine's metabolism. CYP2A6 genetic variants contribute to the interindividual and interethnic variation in nicotine metabolism. We examined the association between the CYP2A6*1B variant and nicotine's in vivo metabolism. Intravenous infusions of deuterium-labeled nicotine were administered to 292 volunteers, 163 of whom were White and did not have common CYP2A6 variants, other than CYP2A6*1B. We discovered three novel CYP2A6*1B variants in the 3'-flanking region of the gene that can confound genotyping assays. We found significant differences between CYP2A6*1A/*1A, CYP2A6*1A/*1B, and CYP2A6*1B/*1B groups in total nicotine clearance (17.2+/-5.2, 19.0+/-6.4, and 20.4+/-5.9, P<0.02), non-renal nicotine clearance (16.4+/-5.0, 18.5+/-6.2, and 19.8+/-5.7, P<0.01), and the plasma trans-3'-hydroxycotinine/cotinine ratio (0.26+/-0.1, 0.26+/-0.1, and 0.34+/-0.1, P<0.001). There were also differences in total nicotine (29.4+/-12.9, 25.8+/-0.12.9, and 22.4+/-12.4, P<0.01), cotinine (29.2+/-8.1, 32.2+/-9.1, and 33.0+/-6.6, P<0.01) and trans-3'-hydroxycotinine (32.4+/-9.1, 34.2+/-12.3, and 41.3+/-11.3, P<0.001) excreted in the urine. We report evidence that CYP2A6*1B genotype is associated with faster nicotine clearance in vivo, which will be important to future CYP2A6 genotype association studies.

Isolation and characterization of the cytochrome P450 gene CYP82E5v2 that mediates nicotine to nornicotine conversion in the green leaves of tobacco

In the species of genus Nicotiana, nicotine to nornicotine conversion is mediated by closely related nicotine N-demethylase (NND) proteins that are encoded by the CYP82E subfamily of cytochrome P450 genes. The diverse number and transcriptional regulation of the NND genes have created large variations in the time and rate of nornicotine production in various Nicotiana species. In tobacco, previous studies have identified the senescence-inducible CYP82E4 gene as an important factor controlling nicotine conversion. Nornicotine is an undesirable alkaloid in tobacco, because it serves as a precursor for N'-nitrosonornicotine, a potent carcinogen in laboratory animals. The objective of this study was to investigate the possible catalytic roles of additional NND genes in shaping the alkaloid profile of tobacco. A PCR-based strategy using primers complementary to conserved regions of CYP82E genes yielded a cDNA, designated CYP82E5v2, which conferred NND activity in heterologous expression studies using yeast as a host. PCR amplification of CYP82E5v2 orthologs revealed that of the two progenitor species of tobacco, CYP82E5v2 was donated by the N. tomentosiformis parent. A comparison of CYP82E4 and CYP82E5v2 expression using qualitative real-time PCR analysis demonstrated that the transcription of CYP82E5v2 was higher in the green leaves of all tobacco genotypes tested, while the expression of CYP82E4 dominated in the senescing leaves of converter tobacco. These results suggest that differentially regulated NND genes regulate nornicotine production in the green and senescing leaves of tobacco and provide tools to reduce nornicotine levels in tobacco leaves.

Antiamnestic effect of alpha7-nicotinic receptor agonist RJR-2403 in middle-aged ovariectomized rats with Alzheimer type dementia

The effects of chronic combined treatment with alpha7-nicotinic cholinergic receptor agonist RJR-2403 (1.0 mg/kg intraperitoneally) or alpha7-nicotinic cholinergic receptor antagonist mecamylamine (1.0 mg/kg intraperitoneally) and 17beta-estradiol (0.5 microg per rat intramuscularly) for 10 days on passive avoidance retention were studied in middle-aged (15 months) ovariectomized rats with experimental Alzheimer type dementia. Chronic treatment with RJR-2403 and 17beta-estradiol had a pronounced antiamnestic effect under conditions of Alzheimer type dementia in middle-aged ovariectomized rats.

Analyses of tobacco alkaloids by cation-selective exhaustive injection sweeping microemulsion electrokinetic chromatography

In this study, an on-line concentration method which coupled cation-selective exhaustive injection (CSEI) sweeping technology with microemulsion electrokinetic chromatography (MEEKC) was used to detect and analyze several tobacco alkaloids (nornicotine, anabasine, anatabine, nicotine, myosmine and cotinine) that are commonly found in various tobacco products. First, the effects of microemulsion compositions (oil, cosurfactant and solution pH) were examined in order to optimize the alkaloid separations in conventional MEEKC. The pH value and the injection length of basic plug were found to be the predominant influences on the alkaloid stacking. This optimal CSEI sweeping MEEKC method provided approximately 180- to 540-fold increase in detection sensitivity in terms of peak height without any loss in separation efficiency when compared to normal MEEKC separation. Furthermore, this proposed CSEI sweeping MEEKC method was applied successfully for the detection of the minor alkaloids nornicotine, anabasine and anatabine in tobacco products.

Endogenous formation of N'-nitrosonornicotine in F344 rats in the presence of some antioxidants and grape seed extract

N'-Nitrosonornicotine (NNN) is one of the most abundant strong carcinogens in unburned tobacco and cigarette smoke and is classified by the International Agency for Research on Cancer as carcinogenic to humans. Human exposure to NNN mainly occurs upon use of tobacco products. It is also possible that additional amounts of NNN are formed endogenously. The goal of this study was to evaluate the inhibitory effect of some antioxidants, including ascorbic acid and grape seed extract (GSE), on endogenous NNN formation in rats treated with nornicotine and sodium nitrite by gavage twice daily for 3 days. The study included four groups of rats: (1) negative control group A, to which no chemical was administered; (2) negative control group B, treated with nornicotine alone (2.5 micromol per gavage); (3) positive control group, to which both nornicotine (2.5 micromol per gavage) and sodium nitrite (7.5 micromol per gavage) were administered; and (4) rats treated with nornicotine (2.5 micromol per gavage), inhibitor (7.5 or 37.5 micromol per gavage), and sodium nitrite (7.5 micromol per gavage). The mean (+/-SD) total amount of NNN in the 3-day urine of rats treated with both nornicotine and sodium nitrite was 4.78 +/- 2.88 nmol. The order of inhibition of endogenous NNN formation in rats at the molar ratio [nitrite]:[inhibitor] 1:5 was as follows: ascorbic acid (91%) > dihydroxyfumaric acid (86%) approximately catechin (85%) > resveratrol (no inhibition). Treatment of rats with grape seed extract did not produce statistically significant inhibition of endogenous nornicotine nitrosation. This is the first study that demonstrates endogenous NNN formation in rats treated with nornicotine and sodium nitrite and effective inhibition of this process by ascorbic acid, dixydroxyfumaric acid, and catechin.