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Mori A, Ito S, Sekine T. A revision of the multiple-path particle dosimetry model focusing on tobacco product aerosol dynamics. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2024; 40:e3796. [PMID: 38185887 DOI: 10.1002/cnm.3796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 10/15/2023] [Accepted: 11/26/2023] [Indexed: 01/09/2024]
Abstract
To assess the health impact of inhaled aerosols, it is necessary to understand aerosol dynamics and the associated dosimetry in the human respiratory tract. Although several studies have measured or simulated the dosimetry of aerosol constituents, the respiratory tract focus areas have been limited. In particular, the aerosols generated from tobacco products are complex composites and simulating their dynamics in the respiratory tract is challenging. To assess the dosimetry of the aerosol constituents of tobacco products, we developed a revised version of the Multiple-Path Particle Dosimetry (MPPD) model, which employs (1) new geometry based on CT-scanned human respiratory tract data, (2) convective mixing in the oral cavity and deep lung, and (3) constituent partitioning between the tissue and air, and clearance. The sensitivity analysis was conducted using aerosols composed of four major constituents of electronic cigarette (EC) aerosols to investigate the parameters that have a significant impact on the results. In addition, the revised model was run with 4 and 10 constituents in ECs and conventional cigarettes (CCs), respectively. Sensitivity analysis revealed that the new modeling and the physicochemical properties of constituents had a considerable impact on the simulated aerosol concentration and dosimetry. The simulations could be carried out within 3 min even when 10 constituents of CC aerosols were analyzed simultaneously. The revised model based on MPPD is an efficient and easy-to-use tool for understanding the aerosol dynamics of CC and EC constituents and their effect on the human body.
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Affiliation(s)
- Akina Mori
- Scientific Product Assessment Center, R&D Group, Japan Tobacco Inc., Yokohama, Japan
| | - Shigeaki Ito
- Scientific Product Assessment Center, R&D Group, Japan Tobacco Inc., Yokohama, Japan
| | - Takashi Sekine
- Scientific Product Assessment Center, R&D Group, Japan Tobacco Inc., Yokohama, Japan
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2
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Zuo Y, Solingapuram Sai KK, Jazic A, Bansode AH, Rose JE, Mukhin AG. Comparison of brain nicotine accumulation from traditional combustible cigarettes and electronic cigarettes with different formulations. Neuropsychopharmacology 2024; 49:740-746. [PMID: 38225397 PMCID: PMC10876700 DOI: 10.1038/s41386-024-01800-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Revised: 12/27/2023] [Accepted: 01/03/2024] [Indexed: 01/17/2024]
Abstract
Rapid brain accumulation is critical for the acute reinforcing effects of nicotine. Although nicotine formulation (free-base vs. protonated or salt) in electronic cigarette (E-cig) liquid affects user satisfaction, its impact on brain nicotine accumulation (BNA) from E-cig use has not been evaluated in comparison with traditional combustible cigarettes (C-cigs) using a within-subjects design. BNA was directly assessed with 29 adult dual users (13 females) of E-cigs and C-cigs, using [11C]nicotine and positron emission tomography (PET). Participants underwent two 15-min upper body (from chest to head) scanning sessions during which they inhaled a single puff of [11C]nicotine-labeled vapor from E-cigs with free-base nicotine or C-cig smoke in a randomized order. Seventeen of them also went through another session during which they inhaled from E-cigs with nicotine salt. A full-body scan was also conducted at each session to measure total absorbed dose of [11C]nicotine. Mean maximum nicotine concentration (Cmax) in brain following inhalation of free-base nicotine E-cig vapor was 19% and 15% lower relative to C-cig smoke and nicotine salt E-cig vapor (ps = 0.014 and 0.043, respectively). The Cmax values did not differ significantly between the C-cig and nicotine salt E-cig. Mean values of time to the maximum concentration (Tmax) were not significantly different between the two types of E-cig, but they were 64% and 40% longer than that for C-cig smoking (ps = 0.0005 and 0.004, respectively). Mean Cmax with C-cigs and free-base nicotine E-cigs were greater in females relative to males and correlated with T1/2 of lung nicotine clearance and participants' pack-years. These results suggest that while E-cigs with free-base nicotine formulation can deliver nicotine rapidly to the brain, those with nicotine salt formulation are capable of even more efficient brain nicotine delivery closely resembling combustible cigarettes. Therefore, nicotine formulation or pH in E-liquid should be considered in evaluation of E-cigs in terms of abuse liability and potential in substituting for combustible cigarettes.
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Affiliation(s)
- Yantao Zuo
- Department of Psychiatry and Behavioral Sciences, Duke University Scholl of Medicine, Durham, NC, 27705, USA
| | - Kiran Kumar Solingapuram Sai
- Department of Radiological Sciences, Atrium Health Wake Forest Baptist Medical Center, Winston-Salem, NC, 27157, USA
| | - Aeva Jazic
- Department of Psychiatry and Behavioral Sciences, Duke University Scholl of Medicine, Durham, NC, 27705, USA
| | - Avinash H Bansode
- Department of Radiological Sciences, Atrium Health Wake Forest Baptist Medical Center, Winston-Salem, NC, 27157, USA
| | - Jed E Rose
- Department of Psychiatry and Behavioral Sciences, Duke University Scholl of Medicine, Durham, NC, 27705, USA
| | - Alexey G Mukhin
- Department of Psychiatry and Behavioral Sciences, Duke University Scholl of Medicine, Durham, NC, 27705, USA.
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Mercier C, Pourchez J, Leclerc L, Forest V. In vitro toxicological evaluation of aerosols generated by a 4th generation vaping device using nicotine salts in an air-liquid interface system. Respir Res 2024; 25:75. [PMID: 38317149 PMCID: PMC10845662 DOI: 10.1186/s12931-024-02697-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 01/22/2024] [Indexed: 02/07/2024] Open
Abstract
BACKGROUND Electronic cigarettes (EC) have gained popularity, especially among young people, with the introduction of fourth-generation devices based on e-liquids containing nicotine salts that promise a smoother vaping experience than freebase nicotine. However, the toxicological effects of nicotine salts are still largely unknown, and the chemical diversity of e-liquids limits the comparison between different studies to determine the contribution of each compound to the cytotoxicity of EC aerosols. Therefore, the aim of this study was to evaluate the toxicological profile of controlled composition e-liquid aerosols to accurately determine the effects of each ingredient based on exposure at the air-liquid interface. METHODS Human lung epithelial cells (A549) were exposed to undiluted aerosols of controlled composition e-liquids containing various ratios of propylene glycol (PG)/vegetable glycerin (VG) solvents, freebase nicotine, organic acids, nicotine salts, and flavoured commercial e-liquids. Exposure of 20 puffs was performed at the air-liquid interface following a standard vaping regimen. Toxicological outcomes, including cytotoxicity, inflammation, and oxidative stress, were assessed 24 h after exposure. RESULTS PG/VG aerosols elicited a strong cytotoxic response characterised by a 50% decrease in cell viability and a 200% increase in lactate dehydrogenase (LDH) production, but had no effects on inflammation and oxidative stress. These effects occurred only at a ratio of 70/30 PG/VG, suggesting that PG is the major contributor to aerosol cytotoxicity. Both freebase nicotine and organic acids had no greater effect on cell viability and LDH release than at a 70/30 PG/VG ratio, but significantly increased inflammation and oxidative stress. Interestingly, the protonated form of nicotine in salt showed a stronger proinflammatory effect than the freebase nicotine form, while benzoic acid-based nicotine salts also induced significant oxidative stress. Flavoured commercial e-liquids was found to be cytotoxic at a threshold dose of ≈ 330 µg/cm². CONCLUSION Our results showed that aerosols of e-liquids consisting only of PG/VG solvents can cause severe cytotoxicity depending on the concentration of PG, while nicotine salts elicit a stronger pro-inflammatory response than freebase nicotine. Overall, aerosols from fourth-generation devices can cause different toxicological effects, the nature of which depends on the chemical composition of the e-liquid.
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Affiliation(s)
- Clément Mercier
- Mines Saint-Etienne, Université Jean Monnet, INSERM, U1059 Sainbiose, Centre CIS, Saint-Etienne, 42023, France.
| | - Jérémie Pourchez
- Mines Saint-Etienne, Université Jean Monnet, INSERM, U1059 Sainbiose, Centre CIS, Saint-Etienne, 42023, France
| | - Lara Leclerc
- Mines Saint-Etienne, Université Jean Monnet, INSERM, U1059 Sainbiose, Centre CIS, Saint-Etienne, 42023, France
| | - Valérie Forest
- Mines Saint-Etienne, Université Jean Monnet, INSERM, U1059 Sainbiose, Centre CIS, Saint-Etienne, 42023, France
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Hofmann JJ, Poulos VC, Zhou J, Sharma M, Parraga G, McIntosh MJ. Review of quantitative and functional lung imaging evidence of vaping-related lung injury. Front Med (Lausanne) 2024; 11:1285361. [PMID: 38327710 PMCID: PMC10847544 DOI: 10.3389/fmed.2024.1285361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 01/08/2024] [Indexed: 02/09/2024] Open
Abstract
Introduction The pulmonary effects of e-cigarette use (or vaping) became a healthcare concern in 2019, following the rapid increase of e-cigarette-related or vaping-associated lung injury (EVALI) in young people, which resulted in the critical care admission of thousands of teenagers and young adults. Pulmonary functional imaging is well-positioned to provide information about the acute and chronic effects of vaping. We generated a systematic review to retrieve relevant imaging studies that describe the acute and chronic imaging findings that underly vaping-related lung structure-function abnormalities. Methods A systematic review was undertaken on June 13th, 2023 using PubMed to search for published manuscripts using the following criteria: [("Vaping" OR "e-cigarette" OR "EVALI") AND ("MRI" OR "CT" OR "Imaging")]. We included only studies involving human participants, vaping/e-cigarette use, and MRI, CT and/or PET. Results The search identified 445 manuscripts, of which 110 (668 unique participants) specifically mentioned MRI, PET or CT imaging in cases or retrospective case series of patients who vaped. This included 105 manuscripts specific to CT (626 participants), three manuscripts which mainly used MRI (23 participants), and two manuscripts which described PET findings (20 participants). Most studies were conducted in North America (n = 90), with the remaining studies conducted in Europe (n = 15), Asia (n = 4) and South America (n = 1). The vast majority of publications described case studies (n = 93) and a few described larger retrospective or prospective studies (n = 17). In e-cigarette users and patients with EVALI, key CT findings included ground-glass opacities, consolidations and subpleural sparing, MRI revealed abnormal ventilation, perfusion and ventilation/perfusion matching, while PET showed evidence of pulmonary inflammation. Discussion and conclusion Pulmonary structural and functional imaging abnormalities were common in patients with EVALI and in e-cigarette users with or without respiratory symptoms, which suggests that functional MRI may be helpful in the investigation of the pulmonary health effects associated with e-cigarette use.
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Affiliation(s)
| | | | - Jiahai Zhou
- Robarts Research Institute, London, ON, Canada
| | - Maksym Sharma
- Robarts Research Institute, London, ON, Canada
- Department of Medical Biophysics, London, ON, Canada
| | - Grace Parraga
- Robarts Research Institute, London, ON, Canada
- Department of Medical Biophysics, London, ON, Canada
- Department of Medical Imaging, Western University, London, ON, Canada
| | - Marrissa J. McIntosh
- Robarts Research Institute, London, ON, Canada
- Department of Medical Biophysics, London, ON, Canada
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Ragab A, Ibrahim SA, Aboul-Magd DS, Baren MH. One-pot synthesis of pyrazolo[4,3- d]thiazole derivatives containing α-aminophosphonate as potential Mur A inhibitors against MDR pathogens with radiosterilization and molecular modeling simulation. RSC Adv 2023; 13:34756-34771. [PMID: 38035237 PMCID: PMC10685179 DOI: 10.1039/d3ra07040a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 11/14/2023] [Indexed: 12/02/2023] Open
Abstract
The present study involves the synthesis of a new series of α-aminophosphonate derivatives in good yields with a simple workup via the Kabachnik-Fields reaction using lithium perchlorate (LiClO4) as a catalyst to facilitate the reaction. All the newly synthesized compounds were confirmed using various physical, spectroscopic, and analytical data, and the obtained results correlated with the proposed molecular structure. The in vitro antimicrobial activities of each compound were evaluated against different clinical isolates. The results indicated that among these derivatives, two compounds (5a and 5b) were the most active and displayed potent activity with MICs in the range from 0.06 to 0.25 μg mL-1 compared with fosfomycin and fluconazole as standard antibiotics. Moreover, the synthesized phosphonates displayed a broad spectrum of bactericidal and fungicidal activities depending on MICs, MBCs/MFCs, and the time-kill kinetics. In addition, the checkerboard assay showed synergistic and partial synergistic activities between the active compounds combined with fosfomycin and fluconazole. Furthermore, the SEM images showed distinct ruptures of the OM integrity of the FOS-R E. coli at their MICs, which was further indicated by the increased EtBr accumulation within the bacterial cells. Moreover, active derivatives revealed MurA inhibitory activity with IC50 values of 3.8 ± 0.39 and 4.5 ± 0.23 μM compared with fosfomycin (IC50 = 12.7 ± 0.27 μM). To our surprise, exposing 5a and 5b compounds to different gamma radiation doses revealed that 7.0 kGy eradicated the microbial load completely. Finally, the results of quantum chemical study supported the binding mode obtained from the docking study performed inside the active site of MurA (PDB: 1UAE), suggesting that these phosphonates may be promising safe candidates for MDR infection therapy clinical trials with no toxic effects on the normal human cells.
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Affiliation(s)
- Ahmed Ragab
- Chemistry Department, Faculty of Science (Boys), Al-Azhar University Nasr City Cairo 11884 Egypt
| | - Seham A Ibrahim
- Chemistry Department, Faculty of Science, Tanta University Tanta 31527 Egypt
| | - Dina S Aboul-Magd
- Drug Radiation Research Department, National Center for Radiation Research and Technology (NCRRT), Egyptian Atomic Energy Authority Egypt
| | - Mohamed H Baren
- Chemistry Department, Faculty of Science, Tanta University Tanta 31527 Egypt
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Chu M, Deng J, Hu H, Wang R, Li D, Chen Z, Liu XA, Lu J. Nicotine transport across calu-3 cell monolayer: effect of nicotine salts and flavored e-liquids. Drug Dev Ind Pharm 2023; 49:628-636. [PMID: 37751149 DOI: 10.1080/03639045.2023.2263791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 09/21/2023] [Indexed: 09/27/2023]
Abstract
OBJECTIVE This study aimed to investigate the transport capability of nicotine across Calu-3 cell monolayer in various nicotine forms, including nicotine freebase, nicotine salts, and flavored e-liquids with nicotine benzoate. SIGNIFICANCE Nicotine is rapidly absorbed from the respiratory system into systemic circulation during e-cigarettes use. However, the mechanism of nicotine transport in the lung has not been well understood yet. This study may offer critical biological evidence and have implications for the use and regulation of e-cigarettes. METHODS The viability of Calu-3 cells after administration of nicotine freebase, nicotine salts and representative e-liquid were evaluated using the MTT assay, and the integrity of the Calu-3 cell monolayer was evaluated by transepithelial electrical resistance measurement and morphological analysis. Further, the nicotine transport capacity across the Calu-3 cell monolayer in various formulations of nicotine was investigated by analysis of nicotine transport amount. RESULTS The findings indicated that nicotine transport occurred passively and was time-dependent across the Calu-3cell monolayer. In addition, the nicotine transport was influenced by the type of nicotine salts and their respective pH value. The nicotine benzoate exhibited the highest apparent permeability coefficient (Papp), and higher nicotine-to-benzoic acid ratios led to higher Papp values. The addition of flavors to e-liquid resulted in increased Papp values, with the most significant increment being observed in tobacco-flavored e-liquid. CONCLUSIONS In summary, the transport capability of nicotine across the Calu-3 cell monolayer was influenced by the pH values of nicotine salts and flavor additives in e-liquids.
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Affiliation(s)
- Ming Chu
- Laboratory of Life and Health Sciences, Shenzhen First Union Technology Co., Ltd, Shenzhen, P.R. China
- Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Key Laboratory of Brain Connectome and Manipulation, Brain Cognition and Brain Disease Institute (BCBDI), Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, P.R. China
| | - Jingjing Deng
- Laboratory of Life and Health Sciences, Shenzhen Health Union Biotechnology Co., Ltd, Shenzhen, P.R. China
| | - Hao Hu
- Laboratory of Life and Health Sciences, Shenzhen First Union Technology Co., Ltd, Shenzhen, P.R. China
| | - Ruoxi Wang
- Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Key Laboratory of Brain Connectome and Manipulation, Brain Cognition and Brain Disease Institute (BCBDI), Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, P.R. China
| | - Ding Li
- Laboratory of Life and Health Sciences, Shenzhen First Union Technology Co., Ltd, Shenzhen, P.R. China
- Laboratory of Life and Health Sciences, Shenzhen Health Union Biotechnology Co., Ltd, Shenzhen, P.R. China
| | - Zuxin Chen
- Shenzhen Key Laboratory of Drug Addiction, Shenzhen Neher Neural Plasticity Laboratory, the Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences (CAS); Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, P.R. China
- University of the Chinese Academy of Sciences, Beijing, P.R. China
| | - Xin-An Liu
- Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Key Laboratory of Brain Connectome and Manipulation, Brain Cognition and Brain Disease Institute (BCBDI), Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, P.R. China
- University of the Chinese Academy of Sciences, Beijing, P.R. China
| | - Jin Lu
- Laboratory of Life and Health Sciences, Shenzhen First Union Technology Co., Ltd, Shenzhen, P.R. China
- Laboratory of Life and Health Sciences, Shenzhen Health Union Biotechnology Co., Ltd, Shenzhen, P.R. China
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Chellian R, Behnood-Rod A, Bruijnzeel AW. Development of Dependence in Smokers and Rodents With Voluntary Nicotine Intake: Similarities and Differences. Nicotine Tob Res 2023; 25:1229-1240. [PMID: 36482774 PMCID: PMC10256892 DOI: 10.1093/ntr/ntac280] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 11/23/2022] [Accepted: 12/05/2022] [Indexed: 07/29/2023]
Abstract
INTRODUCTION Smoking and vaping throughout adolescence and early adulthood lead to nicotine dependence. Nicotine withdrawal is associated with somatic and affective withdrawal symptoms that contribute to smoking and relapse. Affective nicotine withdrawal symptoms in humans include craving for cigarettes, depression, anxiety, trouble sleeping, and cognitive deficits. METHODS Herein, we review clinical studies that investigated nicotine dependence in people who smoke or vape. We also discuss studies that investigated the development of dependence in animals with oral nicotine intake, nicotine aerosol self-administration, and intravenous nicotine self-administration. RESULTS Clinical studies report that adolescents who smoke daily develop nicotine dependence before those who smoke infrequently, but ultimately all smokers become dependent in adulthood. Preclinical studies indicate that rats that self-administer nicotine also become dependent. Rats that self-administer nicotine display somatic withdrawal signs and affective withdrawal signs, including increased anxiety and depressive-like behavior, cognitive deficits, and allodynia. Most nicotine withdrawal signs were observed in rodents with daily (7 days/week) or intermittent long access (23-hour) to nicotine. Clinical smoking studies report symptoms of nicotine dependence in adolescents of both sexes, but virtually all preclinical nicotine self-administration studies have been done with adult male rats. CONCLUSIONS The role of sex and age in the development of dependence in nicotine self-administration studies remains under-investigated. However, the role of sex and age in nicotine withdrawal has been thoroughly evaluated in studies in which nicotine was administered noncontingently. We discuss the need for volitional nicotine self-administration studies that explore the gradual development of dependence during adolescence and adulthood in rodents of both sexes. IMPLICATIONS The reviewed clinical studies investigated the development of nicotine dependence in male and female adolescent and young adult smokers and vapers. These studies indicate that most adolescent smokers and vapers gradually become nicotine dependent. Preclinical studies with rodents show that nicotine intake in widely used self-administration models also leads to dependence. However, almost all animal studies that investigated the development of nicotine dependence have been conducted with adult male rats. To better model smoking and vaping, it is important that nicotine intake in rats or mice starts during adolescence and that both sexes are included.
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Affiliation(s)
| | - Azin Behnood-Rod
- Department of Psychiatry, University of Florida, Gainesville, FL, USA
| | - Adriaan W Bruijnzeel
- Corresponding Author: Adriaan Bruijnzeel, PhD, University of Florida, Department of Psychiatry, 1149 Newell Dr., Gainesville, Florida 32611, USA. Telephone: 352-294-4931; Fax: 352-392-9887; E-mail:
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Solingapuram Sai KK, Rose JE, Mukhin AG. Effect of Electronic Cigarette Liquid pH on Retention of 11C-Nicotine in a Respiratory Tract Model. Nicotine Tob Res 2023; 25:1406-1410. [PMID: 36905343 PMCID: PMC10256878 DOI: 10.1093/ntr/ntad039] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 02/09/2023] [Accepted: 03/09/2023] [Indexed: 03/12/2023]
Abstract
INTRODUCTION Based on our preliminary 11C-nicotine positron emission tomography (PET) imaging studies in humans, we speculated that greater deposition of nicotine in the respiratory tract from electronic cigarettes compared to combustible cigarettes could result from the alkaline pH of typical aerosol-producing electronic cigarette liquids (e-liquids). To address this hypothesis, we assessed the effect of e-liquid pH on the retention of nicotine in vitro using 11C-nicotine, PET, and a human respiratory tract model of nicotine deposition. AIMS AND METHODS A single 2-second 35-mL puff was delivered to a human respiratory tract cast from a 2.8-Ohm cartomizer at 4.1 volts. Immediately after the puff, a 2-second 700-mL air wash-in volume was administered. E-liquids (glycerol and propylene glycol 50/50 vol/vol) containing 24 mg/mL nicotine were mixed with 11C-nicotine. Deposition (retention) of nicotine was assessed using a GE Discovery MI DR PET/CT scanner. Eight e-liquids with different pH values (range 5.3-9.6) were investigated. All experiments were performed at room temperature and at a relative humidity of 70%-80%. RESULTS Retention of nicotine in the respiratory tract cast was pH dependent and the pH-sensitive component of the retention was well described by a sigmoid curve. In total, 50% of the maximal pH-dependent effect was observed at pH 8.0, which is close to the pKa2 of nicotine. CONCLUSIONS The retention of nicotine in the respiratory tract conducting airways is dependent on the e-liquid pH. Lowering the e-liquid pH reduces retention of nicotine. Nonetheless, reduction of the pH below 7 has little effect, consistent with the pKa2 of protonated nicotine. IMPLICATIONS Similar to combustible cigarettes, the retention of nicotine in the human respiratory tract from consumption of electronic cigarettes may have some health consequences and affect nicotine dependence. Here we demonstrated that the retention of nicotine in the respiratory tract is dependent on the e-liquid pH, and lowering pH reduces retention of nicotine in conducting airways of the respiratory tract. Therefore, e-cigarettes with low pH values would result in reduced respiratory tract nicotine exposure and faster delivery of nicotine to the central nervous system (CNS). The latter can be associated with e-cigarette abuse liability and the effectiveness of e-cigarettes as substitutes for combustible cigarettes.
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Affiliation(s)
- Kiran K Solingapuram Sai
- Department of Radiology, Atrium Health Wake Forest Baptist Medical Center, Winston-Salem, NC, USA
| | - Jed E Rose
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC, USA
| | - Alexey G Mukhin
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC, USA
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9
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Mairinger S, Hernández-Lozano I, Zeitlinger M, Ehrhardt C, Langer O. Nuclear medicine imaging methods as novel tools in the assessment of pulmonary drug disposition. Expert Opin Drug Deliv 2022; 19:1561-1575. [PMID: 36255136 DOI: 10.1080/17425247.2022.2137143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
INTRODUCTION Drugs for the treatment of respiratory diseases are commonly administered by oral inhalation. Yet surprisingly little is known about the pulmonary pharmacokinetics of inhaled molecules. Nuclear medicine imaging techniques (i.e. planar gamma scintigraphy, single-photon emission computed tomography [SPECT] and positron emission tomography [PET]) enable the noninvasive dynamic measurement of the lung concentrations of radiolabeled drugs or drug formulations. This review discusses the potential of nuclear medicine imaging techniques in inhalation biopharmaceutical research. AREAS COVERED (i) Planar gamma scintigraphy studies with radiolabeled inhalation formulations to assess initial pulmonary drug deposition; (ii) imaging studies with radiolabeled drugs to assess their intrapulmonary pharmacokinetics; (iii) receptor occupancy studies to quantify the pharmacodynamic effect of inhaled drugs. EXPERT OPINION Imaging techniques hold potential to bridge the knowledge gap between animal models and humans with respect to the pulmonary disposition of inhaled drugs. However, beyond the mere assessment of the initial lung deposition of inhaled formulations with planar gamma scintigraphy, imaging techniques have rarely been employed in pulmonary drug development. This may be related to several technical challenges encountered with such studies. Considering the wealth of information that can be obtained with imaging studies their use in inhalation biopharmaceutics should be further investigated.
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Affiliation(s)
- Severin Mairinger
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.,Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | | | - Markus Zeitlinger
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Carsten Ehrhardt
- School of Pharmacy and Pharmaceutical Sciences and Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - Oliver Langer
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.,Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
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Shegani A, Kealey S, Luzi F, Basagni F, Machado JDM, Ekici SD, Ferocino A, Gee AD, Bongarzone S. Radiosynthesis, Preclinical, and Clinical Positron Emission Tomography Studies of Carbon-11 Labeled Endogenous and Natural Exogenous Compounds. Chem Rev 2022; 123:105-229. [PMID: 36399832 PMCID: PMC9837829 DOI: 10.1021/acs.chemrev.2c00398] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The presence of positron emission tomography (PET) centers at most major hospitals worldwide, along with the improvement of PET scanner sensitivity and the introduction of total body PET systems, has increased the interest in the PET tracer development using the short-lived radionuclides carbon-11. In the last few decades, methodological improvements and fully automated modules have allowed the development of carbon-11 tracers for clinical use. Radiolabeling natural compounds with carbon-11 by substituting one of the backbone carbons with the radionuclide has provided important information on the biochemistry of the authentic compounds and increased the understanding of their in vivo behavior in healthy and diseased states. The number of endogenous and natural compounds essential for human life is staggering, ranging from simple alcohols to vitamins and peptides. This review collates all the carbon-11 radiolabeled endogenous and natural exogenous compounds synthesised to date, including essential information on their radiochemistry methodologies and preclinical and clinical studies in healthy subjects.
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Affiliation(s)
- Antonio Shegani
- School
of Biomedical Engineering & Imaging Sciences, King’s College London, King’s Health Partners, St Thomas’ Hospital, London SE1 7EH, United Kingdom
| | - Steven Kealey
- School
of Biomedical Engineering & Imaging Sciences, King’s College London, King’s Health Partners, St Thomas’ Hospital, London SE1 7EH, United Kingdom
| | - Federico Luzi
- School
of Biomedical Engineering & Imaging Sciences, King’s College London, King’s Health Partners, St Thomas’ Hospital, London SE1 7EH, United Kingdom
| | - Filippo Basagni
- Department
of Pharmacy and Biotechnology, Alma Mater
Studiorum−University of Bologna, via Belmeloro 6, 40126 Bologna, Italy
| | - Joana do Mar Machado
- School
of Biomedical Engineering & Imaging Sciences, King’s College London, King’s Health Partners, St Thomas’ Hospital, London SE1 7EH, United Kingdom
| | - Sevban Doğan Ekici
- School
of Biomedical Engineering & Imaging Sciences, King’s College London, King’s Health Partners, St Thomas’ Hospital, London SE1 7EH, United Kingdom
| | - Alessandra Ferocino
- Institute
of Organic Synthesis and Photoreactivity, Italian National Research Council, via Piero Gobetti 101, 40129 Bologna, Italy
| | - Antony D. Gee
- School
of Biomedical Engineering & Imaging Sciences, King’s College London, King’s Health Partners, St Thomas’ Hospital, London SE1 7EH, United Kingdom,A.G.: email,
| | - Salvatore Bongarzone
- School
of Biomedical Engineering & Imaging Sciences, King’s College London, King’s Health Partners, St Thomas’ Hospital, London SE1 7EH, United Kingdom,S.B.:
email,
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11
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Zuo Y, Mukhin AG, Berg H, Morgan JD, Mintz A, Rose JE, Solingapuram Sai KK. Comparison of brain nicotine uptake from electronic cigarettes and combustible cigarettes. Neuropsychopharmacology 2022; 47:1939-1944. [PMID: 35962133 PMCID: PMC9485116 DOI: 10.1038/s41386-022-01410-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 07/17/2022] [Accepted: 07/22/2022] [Indexed: 11/09/2022]
Abstract
Brain accumulation rate and magnitude are critical for the acute reinforcing effects of nicotine. Despite electronic cigarettes' (E-cigs) appeal as substitutes for traditional combustible cigarettes (C-cigs), brain nicotine accumulation (BNA) from E-cigs has not been compared with that from C-cigs using a within-subjects design. BNA was directly assessed with 16 adult dual users (10 females) of E-cigs (e-liquid pH 9.4) and C-cigs, using 11C-nicotine and positron emission tomography (PET). Participants went through two 15-min head scanning sessions during which they inhaled a single puff of E-cig vapor or C-cig smoke containing 11C-nicotine in a randomized order. A full-body scan was also conducted at each session to measure total absorbed dose of 11C-nicotine. Mean maximum concentration (Cmax) and area under curve of BNA were 22.1% and 22.7% lower, respectively, following E-cig compared with C-cig inhalation. Meanwhile, T1/2 was 2.7 times longer following inhalation of E-cig vapor relative to C-cig smoke (all ps < 0.005). Whole-body imaging indicated greater nicotine retention in the respiratory tract from vapor versus smoke inhalation (p < 0.0001). Following vapor inhalation, nicotine retention in the respiratory tract was correlated with Cmax values of BNA (rs = -0.59, p < 0.02). Our results confirm that E-cigs with alkaline pH e-liquid can deliver nicotine rapidly to the brain, albeit less efficiently than C-cigs partly due to greater airway retention of nicotine. Since brain nicotine uptake mediates reinforcement, these results help elucidate actions of E-cigs in terms of abuse liability and effectiveness in substituting for combustible cigarettes.
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Affiliation(s)
- Yantao Zuo
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC, 27705, USA
| | - Alexey G Mukhin
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC, 27705, USA.
| | - Hannah Berg
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC, 27705, USA
| | - Janiece D Morgan
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC, 27705, USA
| | - Akiva Mintz
- Department of Radiology, Atrium Health Wake Forest Baptist Medical Center, Winston-Salem, NC, 27157, USA
| | - Jed E Rose
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC, 27705, USA
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