Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 542
Filtrar
1.
J Chromatogr A ; 1626: 461361, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797840

RESUMO

The alkaloid enantiomers are well-known to have different physiological and pharmacological effects, and to play an important role in enantioselectivity metabolism with enzymes catalysis in tobacco plants. Here, we developed an improved method for simultaneous and high-precision determination of the individual enantiomers of nornicotine, anatabine and anabasine in four tobacco matrices, based on an achiral gas chromatography-nitrogen phosphorus detector (GCNPD) with commonly available Rtx-200 column using (1S)-(-)-camphanic chloride derivatization. The method development consists of the optimization of extraction and derivatization, screening of achiral column, analysis of the fragmentation mechanisms and evaluation of matrix effect (ME). Under the optimized experimental conditions, the current method exhibited excellent detection capability for the alkaloid enantiomers, with coefficients of determination (R2) > 0.9989 and normality test of residuals P > 0.05 in linear regression parameters. The ME can be neglected for the camphanic derivatives. The limit of detection (LOD) and limit of quantitation (LOQ) ranged from 0.087 to 0.24 µg g - 1 and 0.29 to 0.81 µg g - 1, respectively. The recoveries and within-laboratory relative standard deviations (RSDR) were 94.3%~104.2% and 0.51%~3.89%, respectively. The developed method was successfully applied to determine the enantiomeric profiling of cultivars and curing processes. Tobacco cultivars had a significant impact on the nornicotine, anatabine, anabasine concentration and enantiomeric fraction (EF) of (R)-nornicotine, whereas the only significant change induced by the curing processes was an increase in the EF of (R)-anabasine.


Assuntos
Alcaloides/análise , Anabasina/análise , Cromatografia Gasosa/métodos , Nicotina/análogos & derivados , Piridinas/análise , Tabaco/química , Alcaloides/química , Anabasina/química , Hidrocarbonetos Aromáticos com Pontes/química , Cloretos/química , Lactonas/química , Nicotina/análise , Nicotina/química , Piridinas/química , Estereoisomerismo
2.
Mol Pharmacol ; 98(2): 168-180, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32474444

RESUMO

The two major nicotinic acetylcholine receptors (nAChRs) in the brain are the α4ß2 and α7 subtypes. A "methyl scan" of the pyrrolidinium ring was used to detect differences in nicotine's interactions with these two receptors. Each methylnicotine was investigated using voltage-clamp and radioligand binding techniques. Methylation at each ring carbon elicited unique changes in nicotine's receptor interactions. Replacing the 1'-N-methyl with an ethyl group or adding a second 1'-N-methyl group significantly reduced interaction with α4ß2 but not α7 receptors. The 2'-methylation uniquely enhanced binding and agonist potency at α7 receptors. Although 3'- and 5'-trans-methylations were much better tolerated by α7 receptors than α4ß2 receptors, 4'-methylation decreased potency and efficacy at α7 receptors much more than at α4ß2 receptors. Whereas cis-5'-methylnicotine lacked agonist activity and displayed a low affinity at both receptors, trans-5'-methylnicotine retained considerable α7 receptor activity. Differences between the two 5'-methylated analogs of the potent pyridyl oxymethylene-bridged nicotine analog A84543 were consistent with what was found for the 5'-methylnicotines. Computer docking of the methylnicotines to the Lymnaea acetylcholine binding protein crystal structure containing two persistent waters predicted most of the changes in receptor affinity that were observed with methylation, particularly the lower affinities of the cis-methylnicotines. The much smaller effects of 1'-, 3'-, and 5'-methylations and the greater effects of 2'- and 4'-methylations on nicotine α7 nAChR interaction might be exploited for the design of new drugs based on the nicotine scaffold. SIGNIFICANCE STATEMENT: Using a comprehensive "methyl scan" approach, we show that the orthosteric binding sites for acetylcholine and nicotine in the two major brain nicotinic acetylcholine receptors interact differently with the pyrrolidinium ring of nicotine, and we suggest reasons for the higher affinity of nicotine for the heteromeric receptor. Potential sites for nicotine structure modification were identified that may be useful in the design of new drugs targeting these receptors.


Assuntos
Nicotina/análogos & derivados , Piridinas/síntese química , Receptores Nicotínicos/metabolismo , Receptor Nicotínico de Acetilcolina alfa7/metabolismo , Animais , Sítios de Ligação , Masculino , Metilação , Simulação de Acoplamento Molecular , Estrutura Molecular , Nicotina/química , Piridinas/química , Piridinas/farmacologia , Ratos , Relação Estrutura-Atividade , Xenopus laevis
3.
Chemosphere ; 249: 126153, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32058129

RESUMO

In this study, we determined DNA damage and chromosome breakage (indicators of genotoxicity) and cell viability (an indicator of cytotoxicity) in human lymphoblastoid TK6 and Chinese hamster ovary (CHO) cells treated with 33 e-liquids using in vitro single cell gel (comet), micronucleus (MN), and trypan blue assays, respectively. We also measured the contents of nicotine, five phthalate esters, and DL-menthol in the e-liquids to examine their effects on DNA damage, chromosome breakage, and cell viability. Our chemical analyses showed that: (1) six e-liquids had nicotine ≥2-fold higher than the manufacture's label claim (2-3.5 mg); (2) both dimethyl- and dibutyl-phthalate levels were >0.1 µg/g, i.e., their threshold limits as additives in cosmetics; and (3) the DL-menthol contents ranged from 0.0003 to 85757.2 µg/g, with those of two e-liquids being >1 mg/g, the threshold limit for trigging sensory irritation. Though all the e-liquids induced DNA damage in TK6 cells, 20 resulted in cell viabilities ≤75%, indicating cytotoxicity, yet the inverse relationship between cell viability and DNA damage (r = -0.628, p = 0.003) might reflect their role as pro-apoptotic and DNA damage inducers. Fifteen e-liquids induced MN% in TK6 cells ≥3-fold that of untreated cells. Some of the increase in %MN might be false due to high cytotoxicity, yet six brands showed acceptable cell viabilities (59-71%), indicating chromosome damage. DNA damage and %MN increased when the TK6 cells were exposed to metabolic activation. The CHO cells were less sensitive to the genotoxic effects of the e-liquids than the TK6 cells. DL-menthol was found to be associated with decreased cell viability and increased DNA damage, even at low levels. We cannot dismiss the presence of other ingredients in e-liquids with cytotoxic/genotoxic properties since out of the 63 different flavors, 47 induced DNA damage (≥3-folds), and 26 reduced cell viability (≤75%) in TK6 cells.


Assuntos
Vapor do Cigarro Eletrônico/química , Ácidos Ftálicos/química , Animais , Células CHO , Sobrevivência Celular/efeitos dos fármacos , Cricetinae , Cricetulus , Dano ao DNA , Dibutilftalato/farmacologia , Vapor do Cigarro Eletrônico/análise , Vapor do Cigarro Eletrônico/toxicidade , Ésteres/química , Humanos , Mentol/química , Mentol/toxicidade , Testes para Micronúcleos/métodos , Nicotina/química , Nicotina/toxicidade
4.
Artigo em Inglês | MEDLINE | ID: mdl-31783619

RESUMO

Most recent studies on electronic cigarettes (e-cigs) have been carried out using vaping regimens consistent with mouth-to-lung inhalation (MTL) and not with direct-to-lung (DTL) inhalation. This paper aimed to characterizing the influence of inhalation properties (puff duration, puff volume, airflow rate) on the mass of vaporized e-liquid (MVE). Because the literature on DTL is non-existent, an intense vaping regimen consistent with DTL inhalation (i.e., puff volume = 500 mL) was defined. The use of a low or standard (ISO/DIS 20768) regimen and the proposed intense vaping regimen were first compared using the Cubis 1 Ω atomizer on a large power range, and then by using two atomizers below 1 Ω and two others above 1 Ω on their respective power ranges. An analysis of the e-cig efficiency on the e-liquid vaporization was proposed and calculated for each MVE. The intense vaping regimen allowed a broader power range in optimal heating conditions. MVE linearly increased with the supplied power, up to over-heating conditions at higher powers. Moreover, the e-cigs' efficiencies were higher when low-resistance atomizers were tested at high powers. All these results highlighted that the generated vapor might be better evacuated when an intense vaping regimen is used, and illustrate the obvious need to define a suitable standardized vaping regimen consistent with DTL inhalation.


Assuntos
Sistemas Eletrônicos de Liberação de Nicotina , Nicotina/química , Vaping , Aerossóis , Sistemas Eletrônicos de Liberação de Nicotina/normas , Gases , Calefação , Humanos , Modelos Teóricos , Nebulizadores e Vaporizadores , Volatilização
5.
Molecules ; 24(20)2019 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-31652614

RESUMO

Nicotinic acetylcholine receptors (nAChRs), serotonin transporters (SERT) and dopamine transporters (DAT) represent targets for the development of novel nicotinic derivatives acting as multiligands associated with different health conditions, such as depressive, anxiety and addiction disorders. In the present work, a series of functionalized esters structurally related to acetylcholine and nicotine were synthesized and pharmacologically assayed with respect to these targets. The synthesized compounds were studied in radioligand binding assays at α4ß2 nAChR, h-SERT and h-DAT. SERT experiments showed not radioligand [3H]-paroxetine displacement, but rather an increase in the radioligand binding percentage at the central binding site was observed. Compound 20 showed Ki values of 1.008 ± 0.230 µM for h-DAT and 0.031 ± 0.006 µM for α4ß2 nAChR, and [3H]-paroxetine binding of 191.50% in h-SERT displacement studies, being the only compound displaying triple affinity. Compound 21 displayed Ki values of 0.113 ± 0.037 µM for α4ß2 nAChR and 0.075 ± 0.009 µM for h-DAT acting as a dual ligand. Molecular docking studies on homology models of α4ß2 nAChR, h-DAT and h-SERT suggested potential interactions among the compounds and agonist binding site at the α4/ß2 subunit interfaces of α4ß2 nAChR, central binding site of h-DAT and allosteric modulator effect in h-SERT.


Assuntos
Acetilcolina/análogos & derivados , Proteínas da Membrana Plasmática de Transporte de Dopamina/química , Nicotina/análogos & derivados , Receptores Nicotínicos/química , Proteínas da Membrana Plasmática de Transporte de Serotonina/química , Acetilcolina/agonistas , Acetilcolina/síntese química , Acetilcolina/química , Regulação Alostérica , Sítios de Ligação , Dopamina/química , Agonistas de Dopamina/química , Proteínas da Membrana Plasmática de Transporte de Dopamina/agonistas , Ésteres/química , Células HEK293 , Humanos , Ligantes , Simulação de Acoplamento Molecular , Nicotina/agonistas , Nicotina/síntese química , Nicotina/química , Agonistas Nicotínicos/química , Pirrolidinas/química , Ensaio Radioligante , Proteínas da Membrana Plasmática de Transporte de Serotonina/agonistas , Relação Estrutura-Atividade
6.
Expert Opin Drug Deliv ; 16(11): 1193-1203, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31495244

RESUMO

Introduction: Electronic cigarettes (e-cigarettes) are a rapidly evolving class of tobacco products intended to deliver nicotine to users. There are many types of e-cigarettes available and the most popular type today in the United States are 'pod' based devices that use high nicotine concentration liquids. Understanding the nicotine delivery capabilities of e-cigarettes is imperative for understanding their addictive potential and safety profile, informing regulation, and revealing their potential use as smoking cessation aids. Areas covered: This review discusses nicotine content of e-cigarettes, effectiveness of nicotine aerosolization by devices, delivery of nicotine to users, and user and device characteristics that impact each of these. Expert opinion: Modern e-cigarettes have the potential to deliver equal or more nicotine compared to a tobacco cigarette. Future research needs to identify the nicotine delivery profiles likely to benefit public health and the means to regulate them appropriately while also identifying those that are likely to cause harm. Public health benefit accrues if e-cigarettes help smokers quit combustible cigarettes completely. Harm is possible if inadequate nicotine delivery undermines cessation attempts, e-cigarettes facilitate continued combustible cigarette use, long-term e-cigarette use is associated with substantial morbidity/mortality, and/or e-cigarettes increase the initiation of combustible cigarette use among never smokers.


Assuntos
Sistemas Eletrônicos de Liberação de Nicotina , Nicotina/administração & dosagem , Aerossóis , Animais , Desenho de Equipamento , Humanos , Nicotina/sangue , Nicotina/química , Nicotina/farmacocinética
7.
Biosens Bioelectron ; 143: 111598, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31442753

RESUMO

Herein, we report the anionic surfactant, ethylene diamine tetraacetic acid (EDTA), mediated synthesis of WO3 nanoparticles and its subsequent modification through gamma irradiation (GI) and electrochemical immobilization with nicotinamide adenine dinucleotide (NAD). Glassy carbon electrode (GCE) modified with GI-WO3 NPs and the enzyme NAD exhibited strong electro-oxidation of three important biomolecules such as norepinephrine (NEP), melatonin (MEL) and nicotine (NIC) in 0.1 M phosphate buffer saline (PBS) at physiological pH of 7. Square wave voltammetry (SWV) studies exhibited three well-defined peaks at potentials of 120, 570 and 840 mV, corresponding to the oxidation of NEP, MEL and NIC respectively, indicating that simultaneous determination of these compounds is feasible at the NAD/GI EDTA-WO3/GCE. The proposed sensor displayed a wide linear range of 0.010-1000 µM with the lowest detection limit of 1.4 nM for NEP, 2.6 nM for MEL and 1.7 nM for NIC respectively. Furthermore, the modified electrode was successfully applied to detect NEP, MEL and NIC in pharmaceutical and cigarette samples with excellent selectivity and reproducibility.


Assuntos
Técnicas Biossensoriais , Melatonina/isolamento & purificação , Nicotina/isolamento & purificação , Norepinefrina/isolamento & purificação , Técnicas Eletroquímicas , Limite de Detecção , Melatonina/química , NAD/química , Nanopartículas/química , Nanotubos de Carbono/química , Nicotina/química , Norepinefrina/química , Óxidos/química , Tungstênio/química
8.
Food Chem Toxicol ; 133: 110727, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31377138

RESUMO

Use of the e-liquid flavourings diacetyl and acetyl propionyl has raised concerns that they might cause respiratory diseases amongst vapers. Product surveys show that these compounds, plus a less toxic alternative, acetoin, are widely used in e-liquids. We have investigated the chemistry of acetoin, acetyl propionyl and diacetyl in e-liquids. They are reactive, with concentrations falling substantially over time. Acetyl propionyl is the most reactive, diacetyl less so, and acetoin significantly more stable. Their reactivity is pH-enhanced when nicotine is present in the e-liquid. Of major concern, we found that acetoin generates diacetyl in e-liquids. We found diacetyl formation in all acetoin-containing e-liquids, but it is not an acetoin-contaminant. Diacetyl concentrations were proportional to acetoin content, grew over time, and formation was accelerated by nicotine. E-liquids stored for up to 18 months contained significant diacetyl, and reduced acetoin levels, showing that acetoin is a long-term diacetyl source. Other reaction pathways operate, and we advance mechanisms to explain this area of e-liquid chemistry. Acetoin use in e-liquids is an inevitable source of diacetyl exposure for e-cigarette users. Acetoin, acetyl propionyl and diacetyl are avoidable hazards for vapers, and we recommend e-liquid manufacturers move away from their use in e-liquid formulations.


Assuntos
Acetoína/química , Diacetil/síntese química , Sistemas Eletrônicos de Liberação de Nicotina , Aromatizantes/química , Acetoína/análise , Diacetil/análise , Estabilidade de Medicamentos , Aromatizantes/análise , Glicerol/química , Concentração de Íons de Hidrogênio , Nicotina/química , Oxirredução , Pentanonas/análise , Propilenoglicol/química
9.
BMC Biotechnol ; 19(1): 56, 2019 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-31375100

RESUMO

BACKGROUND: Smoking and tobacco use continue to be the largest preventable causes of death globally. A novel therapeutic approach has recently been proposed: administration of an enzyme that degrades nicotine, the main addictive component of tobacco, minimizing brain exposure and reducing its reinforcing effects. Pre-clinical proof of concept has been previously established through dosing the amine oxidase NicA2 from Pseudomonas putida in rat nicotine self-administration models of addiction. RESULTS: This paper describes efforts towards optimizing NicA2 for potential therapeutic use: enhancing potency, improving its pharmacokinetic profile, and attenuating immunogenicity. Libraries randomizing residues located in all 22 active site positions of NicA2 were screened. 58 single mutations with 2- to 19-fold enhanced catalytic activity compared to wt at 10 µM nicotine were identified. A novel nicotine biosensor assay allowed efficient screening of the many primary hits for activity at nicotine concentrations typically found in smokers. 10 mutants with improved activity in rat serum at or below 250 nM were identified. These catalytic improvements translated to increased potency in vivo in the form of further lowering of nicotine blood levels and nicotine accumulation in the brains of Sprague-Dawley rats. Examination of the X-ray crystal structure suggests that these mutants may accelerate the rate limiting re-oxidation of the flavin adenine dinucleotide cofactor by enhancing molecular oxygen's access. PEGylation of NicA2 led to prolonged serum half-life and lowered immunogenicity observed in a human HLA DR4 transgenic mouse model, without impacting nicotine degrading activity. CONCLUSIONS: Systematic mutational analysis of the active site of the nicotine-degrading enzyme NicA2 has yielded 10 variants that increase the catalytic activity and its effects on nicotine distribution in vivo at nicotine plasma concentrations found in smokers. In addition, PEGylation substantially increases circulating half-life and reduces the enzyme's immunogenic potential. Taken together, these results provide a viable path towards generation of a drug candidate suitable for human therapeutic use in treating nicotine addiction.


Assuntos
Monoaminoxidase/metabolismo , Nicotina/metabolismo , Tabagismo/metabolismo , Animais , Proteínas de Bactérias/administração & dosagem , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Domínio Catalítico/genética , Humanos , Camundongos , Modelos Moleculares , Monoaminoxidase/química , Monoaminoxidase/genética , Mutação , Nicotina/química , Ligação Proteica , Domínios Proteicos , Pseudomonas putida/enzimologia , Pseudomonas putida/genética , Ratos Sprague-Dawley , Tabagismo/enzimologia , Tabagismo/terapia
10.
Molecules ; 24(15)2019 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-31344816

RESUMO

Neuronal α4ß2 nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels (LGIC) that have been implicated in nicotine addiction, reward, cognition, pain disorders, anxiety, and depression. Nicotine has been widely used as a template for the synthesis of ligands that prefer α4ß2 nAChRs subtypes. The most important therapeutic use for α4ß2 nAChRs is as replacement therapy for smoking cessation and withdrawal and the most successful therapeutic ligands are partial agonists. In this case, we use the N-methylpyrrolidine moiety of nicotine to design and synthesize new α4ß2 nicotinic derivatives, coupling the pyrrolidine moiety to an aromatic group by introducing an ether-bonded functionality. Meta-substituted phenolic derivatives were used for these goals. Radioligand binding assays were performed on clonal cell lines of hα4ß2 nAChR and two electrode voltage-clamp experiments were used for functional assays. Molecular docking was performed in the open state of the nAChR in order to rationalize the agonist activity shown by our compounds.


Assuntos
Nicotina/química , Nicotina/farmacologia , Agonistas Nicotínicos/química , Agonistas Nicotínicos/farmacologia , Receptores Nicotínicos/química , Ligação Competitiva , Relação Dose-Resposta a Droga , Humanos , Cinética , Conformação Molecular , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Estrutura Molecular , Nicotina/análogos & derivados , Ligação Proteica , Relação Estrutura-Atividade
11.
Biomed Chromatogr ; 33(10): e4634, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31257625

RESUMO

Plasma concentrations of nicotine and its active metabolite cotinine are highly correlated with its biological effects. A UHPLC-MS/MS method was developed, validated and applied for nicotine and cotinine analysis in mice plasma. Chromatographic separation was achieved on a BEH HILIC column using acetonitrile (0.1% formic acid) and 10 mm ammonium formate as mobile phase. The gradient elution was performed at 0.4 mL/min with a run time of 3.6 min. The quantitative ion transition was m/z 163.1 > 130.0 for nicotine, m/z 177.1 > 80.0 for cotinine and m/z 167.1 > 134.0 for nicotine-D4 (internal standard, IS). For both nicotine and cotinine, the calibration range was 5-500 ng/mL with 5 ng/mL as the lower limit of quantitation, and the intra- and inter-day bias and imprecision were -4.61-12.00% and <11.12%. The IS normalized recovery was 90.62-98.95% for nicotine and 89.18-101.53% for cotinine, and the IS normalized matrix factor was 106.00-116.44% for nicotine and 100.34-109.85% for cotinine. Both nicotine and cotinine were stable under conventional storage conditions. The validated method has been applied to a pharmacokinetic study in mice to calculate the pharmacokinetic parameters for both analytes.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Cotinina/sangue , Nicotina/sangue , Espectrometria de Massas em Tandem/métodos , Animais , Cotinina/química , Cotinina/farmacocinética , Modelos Lineares , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Nicotina/química , Nicotina/farmacocinética , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
13.
Structure ; 27(7): 1171-1183.e3, 2019 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-31130483

RESUMO

Nicotinic acetylcholine receptors (nAChRs) modulate synaptic transmission in the nervous system. These receptors have emerged as therapeutic targets in drug discovery for treating several conditions, including Alzheimer's disease, pain, and nicotine addiction. In this in silico study, we use a combination of equilibrium and nonequilibrium molecular dynamics simulations to map dynamic and structural changes induced by nicotine in the human α4ß2 nAChR. They reveal a striking pattern of communication between the extracellular binding pockets and the transmembrane domains (TMDs) and show the sequence of conformational changes associated with the initial steps in this process. We propose a general mechanism for signal transduction for Cys-loop receptors: the mechanistic steps for communication proceed firstly through loop C in the principal subunit, and are subsequently transmitted, gradually and cumulatively, to loop F of the complementary subunit, and then to the TMDs through the M2-M3 linker.


Assuntos
Bicamadas Lipídicas/química , Nicotina/química , Fosfatidilcolinas/química , Subunidades Proteicas/química , Receptores Nicotínicos/química , Transdução de Sinais , Sequência de Aminoácidos , Sítios de Ligação , Cristalografia por Raios X , Humanos , Concentração de Íons de Hidrogênio , Ligantes , Bicamadas Lipídicas/metabolismo , Simulação de Dinâmica Molecular , Nicotina/metabolismo , Fosfatidilcolinas/metabolismo , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , Multimerização Proteica , Subunidades Proteicas/metabolismo , Receptores Nicotínicos/metabolismo , Termodinâmica
14.
Mol Pharm ; 16(6): 2766-2775, 2019 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-31075204

RESUMO

Adjuvants are a critical component for vaccines, especially for a poorly immunogenic antigen, such as nicotine. However, the impact of adjuvant release rate from a vaccine formulation on its immunogenicity has not been well illustrated. In this study, we fabricated a series of hybrid-nanoparticle-based nicotine vaccines to study the impact of adjuvant release rate on their immunological efficacy. It was found that the nanovaccine with a medium or slow adjuvant release rate induced a significantly higher anti-nicotine antibody titer than that with a fast release rate. Furthermore, the medium and slow adjuvant release rates resulted in a significantly lower brain nicotine concentration than the fast release rate after nicotine challenge. All findings suggest that adjuvant release rate affects the immunological efficacy of nanoparticle-based nicotine vaccines, providing a potential strategy to rationally designing vaccine formulations against psychoactive drugs or even other antigens. The hybrid-nanoparticle-based nicotine vaccine with an optimized adjuvant release rate can be a promising next-generation immunotherapeutic candidate against nicotine.


Assuntos
Nanopartículas/química , Nicotina/química , Vacinas/química , Adjuvantes Imunológicos , Animais , Feminino , Cinética , Camundongos , Camundongos Endogâmicos BALB C
15.
Pharmacol Res Perspect ; 7(2): e00468, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30906561

RESUMO

Common variation in the CYP2B6 gene, encoding the cytochrome P450 2B6 enzyme, is associated with substrate-specific altered clearance of multiple drugs. CYP2B6 is a minor contributor to hepatic nicotine metabolism, but the enzyme has been proposed as relevant to nicotine-related behaviors because of reported CYP2B6 mRNA expression in human brain tissue. Therefore, we hypothesized that CYP2B6 variants would be associated with altered nicotine oxidation, and that nicotine metabolism by CYP2B6 would be detected in human brain microsomes. We generated recombinant enzymes in insect cells corresponding to nine common CYP2B6 haplotypes and demonstrate genetically determined differences in nicotine oxidation to nicotine iminium ion and nornicotine for both (S) and (R)-nicotine. Notably, the CYP2B6.6 and CYP2B6.9 variants demonstrated lower intrinsic clearance relative to the reference enzyme, CYP2B6.1. In the presence of human brain microsomes, along with nicotine-N-oxidation, we also detect nicotine oxidation to nicotine iminium ion. However, unlike N-oxidation, this activity is NADPH independent, does not follow Michaelis-Menten kinetics, and is not inhibited by NADP or carbon monoxide. Furthermore, metabolism of common CYP2B6 probe substrates, methadone and ketamine, is not detected in the presence of brain microsomes. We conclude that CYP2B6 metabolizes nicotine stereoselectively and common CYP2B6 variants differ in nicotine metabolism activity, but did not find evidence of CYP2B6 activity in human brain.


Assuntos
Encéfalo/metabolismo , Citocromo P-450 CYP2B6/metabolismo , Microssomos/metabolismo , Nicotina/metabolismo , Polimorfismo de Nucleotídeo Único , Idoso , Idoso de 80 Anos ou mais , Encéfalo/citologia , Citocromo P-450 CYP2B6/genética , Feminino , Humanos , Ketamina/metabolismo , Masculino , Metadona/metabolismo , Pessoa de Meia-Idade , Nicotina/análogos & derivados , Nicotina/química , Oxirredução , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Estereoisomerismo , Tabagismo/genética
16.
J Pharm Biomed Anal ; 169: 225-234, 2019 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-30877934

RESUMO

The electronic cigarette (e-cigarette) has emerged as a popular alternative to the traditional hazardous tobacco cigarette. The substantial increase in e-cigarette use also urgently calls for controlling the quality of e-cigarette refill liquid products (e-liquids). Currently, the most important quality indicator of e-liquid products is the quantification of nicotine and its related impurities. Although different methods have been published to measure nicotine and impurity levels, the majority of them use a targeted LC-MS/MS approach. There is, however, a need for more robust quantification methods that are easy to implement in most control (industrial and governmental) laboratories. Therefore, in this study, a simple dilute-and-shoot UHPLC-DAD method has been developed and validated for the simultaneous quantification of nicotine and its alkaloid impurities in electronic cigarette refills. An optimal separation of the alkaloids was achieved in a runtime of 11 min. The method was successfully validated using the "total error" approach in accordance with the validation requirements of ISO-17025. During this validation, interference between the target components and a number of popular flavouring compounds such as vanillin, maltol, ethylacetate, etc. could be excluded. In addition, small changes to the column temperature, pH and molar concentration of the mobile phase buffer were deliberately introduced in order to assess the robustness of the method. Only a slightly different outcome between the newly developed UV-detection method and the targeted MS approach was found, due to the sensitivity of the different detection techniques. However, in the context of quality control of nicotine related impurities, for which the European Pharmacopoeia limits are currently applied, the sensitivity of the UHPLC-DAD method was found to be within the acceptable range. Despite the somewhat lower selectivity of the newly developed UV-detection technique versus a targeted LC-MS/MS approach, it may be concluded that this method is a suitable alternative for quality control purposes.


Assuntos
Alcaloides/química , Nicotina/química , Cromatografia Líquida de Alta Pressão/métodos , Sistemas Eletrônicos de Liberação de Nicotina/métodos , Aromatizantes/química , Limite de Detecção , Espectrometria de Massas em Tandem/métodos
17.
Tob Control ; 28(3): 352-355, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30385649

RESUMO

BACKGROUND: The US Food and Drug Administration recently issued an advanced notice of proposed rule-making for reducing the nicotine content in cigarettes to a minimally addictive level. Very little is known about whether use of very low nicotine content (VLNC) cigarettes affects support for a nicotine reduction policy. OBJECTIVE: This study examined the effects of using VLNC versus usual brand (UB) cigarettes on support for a nicotine reduction policy and determined whether participant characteristics and responses to VLNC cigarettes were associated with policy support. METHODS: Participants from a cigarette trial who were assigned to either 0.4 mg nicotine/g tobacco research cigarettes or their UB for 6 weeks were asked about their support for the policy. χ2 tests were used to compare support for the policy between cigarette conditions and logistic regression analyses were conducted to assess covariates associated with policy support. FINDINGS: Policy support did not differ by condition. After 6 weeks of using VLNC cigarettes, 50% of participants supported the policy, 26% opposed and 24% responded 'Don't Know'. Support was higher among those adherent to smoking only VLNC cigarettes (65%) compared with those who were non-adherent (44%). Older participants and those interested in quitting had increased odds of support. Cigarette satisfaction, perceived harm and perceived nicotine content were not significantly associated with support. CONCLUSIONS: Smoking VLNC cigarettes did not affect support for a nicotine reduction policy. Understanding predictors of policy support and opposition will help public health officials to maximise the public health acceptance and impact of this policy (ClinicalTrials.gov Identifier: NCT01681875 Post-Results).


Assuntos
Fumar Cigarros/prevenção & controle , Nicotina/química , Abandono do Hábito de Fumar/métodos , Produtos do Tabaco , Método Duplo-Cego , Feminino , Humanos , Masculino , Saúde Pública , Política Pública , Fumantes/estatística & dados numéricos , Dispositivos para o Abandono do Uso de Tabaco
18.
Cancer Lett ; 445: 1-10, 2019 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-30583077

RESUMO

We previously demonstrated that some N-biphenylanilides caused cell-cycle arrest at G2/M transition in breast cancer cells. Among them we choose three derivatives, namely PTA34, PTA73 and RS35 for experimentation in solid tumor cell lines, classical Hodgkin Lymphoma (cHL) cell lines and bona fide normal cell lines. Almost all tumor cells were sensitive to compounds in the nanomolar range whereas, they were not cytotoxic to normal ones. Interestingly the compounds caused a strong G2/M phase arrest in cHL cell lines, thus, here we investigated whether they affected the integrity of microtubules in such cells. We found that they induced a long prometaphase arrest, followed by induction of apoptosis which involved mitochondria. PTA73 and RS35 induced the mitotic arrest through the fragmentation of microtubules which prevented the kinethocore-mitotic spindle interaction and the exit from mitosis. PTA34 is instead a tubulin-targeting agent because it inhibited the tubulin polymerization as vinblastine. As such, PTA34 maintained the Cyclin B1-CDK1 regulatory complex activated during the G2/M arrest while inducing the inactivation of Bcl-2 through phosphorylation in Ser70, the degradation of Mcl-1 and a strong activation of BIML and BIMS proapoptotic isoforms. In addition PTA34 exerted an antiangiogenic effect by suppressing microvascular formation.


Assuntos
Antimitóticos/síntese química , Compostos de Bifenilo/síntese química , Doença de Hodgkin/metabolismo , Nicotina/química , Antimitóticos/química , Antimitóticos/farmacologia , Compostos de Bifenilo/química , Compostos de Bifenilo/farmacologia , Proteína Quinase CDC2/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Ciclina B1/metabolismo , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Doença de Hodgkin/tratamento farmacológico , Humanos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Estrutura Molecular , Prometáfase/efeitos dos fármacos
19.
Bioorg Med Chem ; 27(1): 100-109, 2019 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-30503413

RESUMO

The pyridine-derived biomolecules are of considerable interest in developing medicinal compounds with various specific activities. Novel ammonium salts of pyridoxine, (S)-(-)-nicotine and nicotinamide with O,O-diorganyl dithiophosphoric acids (DTPA) were synthesized and characterized. The complexation of chiral monoterpenyl DTPA, including (S)-(-)-menthyl, (R)-(+)-menthyl, (1R)-endo-(+)-fenchyl, (1S,2S,3S,5R)-(+)-isopinocampheolyl derivatives, with pyridoxine and nicotine provided effective antibacterial compounds 3a,b,e,f, and 5a,b,d,f with MIC values against Gram-positive bacteria as low as 10 µM (6 µg/mL). Two selected pyridoxine and nicotine salts based on menthyl DTPA 3a and 5a were similarly active against antibiotic-resistant bacteria from burn wounds including MRSA. The compounds had enhanced amphiphilic and hemolytic properties and effectively altered surface characteristics and matrix-secreting ability of P. aeroginosa and S. aureus. MBC/MIC ratios of 3a and 5a suggested the bactericidal mode of their action. Furthermore, the compounds exhibited moderate cytotoxicity towards human skin fibroblasts (IC50 = 48.6 and 57.6 µM, respectively, 72 h), encouraging their further investigation as potential antimicrobials against skin and wound infections.


Assuntos
Antibacterianos/farmacologia , Niacinamida/farmacologia , Nicotina/farmacologia , Fosfatos/farmacologia , Piridoxina/farmacologia , Antibacterianos/síntese química , Antibacterianos/química , Antibacterianos/toxicidade , Fibroblastos/efeitos dos fármacos , Bactérias Gram-Negativas/efeitos dos fármacos , Hemólise/efeitos dos fármacos , Humanos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Niacinamida/síntese química , Niacinamida/química , Niacinamida/toxicidade , Nicotina/síntese química , Nicotina/química , Nicotina/toxicidade , Fosfatos/síntese química , Fosfatos/química , Fosfatos/toxicidade , Piridoxina/síntese química , Piridoxina/química , Piridoxina/toxicidade , Staphylococcus epidermidis/efeitos dos fármacos
20.
J Aerosol Med Pulm Drug Deliv ; 32(1): 47-53, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30376396

RESUMO

BACKGROUND: Electronic cigarettes (ECIGs) are widely used, but their health effects are not well known. ECIG exposure is difficult to quantify, and a direct measurement of deposition would be beneficial to in vivo and in vitro toxicity studies. The aim of this study was to demonstrate effective radiolabeling of an ECIG. METHODS: A technetium-99m-labeled carbon ultrafine (TCU) aerosol was generated and introduced to a fourth-generation ECIG before nucleation and aerosol formation. The aerosolized e-liquid was a commercially available strawberry flavor containing 1.2% nicotine in a 55% propylene glycol and 45% vegetable glycerine base. An ECIG power setting of 100 W was selected. Mass and radioactivity were measured on each stage within a Sierra Cascade Impactor at 14 L/min to verify the labeling technique using the calculated aerodynamic diameters. A strong positive correlation (R2 > 0.95) between the percent activity and percent mass deposition on each stage provides a reliable validation of colocation. RESULTS: Unlabeled ECIG aerosol from the chosen e-liquid produced a mass median aerodynamic diameter (MMAD) of 0.85 µm. An ECIG labeled with TCU produced an aerosol with an activity median aerodynamic diameter of 0.84 µm and an MMAD of 0.84 µm. The relative mass versus radioactivity on each plate was highly correlated (average R2 = 0.973, p < 0.001). CONCLUSION: A TCU radiolabel was generated and shown to associate with the mass of an aerosol produced by a typical commercially available ECIG. Thus, the radioactivity of the deposited aerosol may be used to determine ECIG aerosol deposition for the future in vivo and in vitro dosimetry studies of the third- and fourth-generation ECIGs.


Assuntos
Carbono/química , Sistemas Eletrônicos de Liberação de Nicotina , Nicotina/química , Agonistas Nicotínicos/química , Tecnécio/química , Vaping , Administração por Inalação , Aerossóis , Carbono/administração & dosagem , Nicotina/administração & dosagem , Agonistas Nicotínicos/administração & dosagem , Tamanho da Partícula , Material Particulado , Tecnécio/administração & dosagem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA