Interactive effects of protonated nicotine concentration and device power on ENDS nicotine delivery, puff topography, and subjective effects.

Electronic nicotine delivery systems (ENDSs) produce an aerosol by heating a liquid that often contains nicotine. The nicotine can be protonated that may make the aerosol easier to inhale than freebase nicotine. This study's purpose is to determine, in cigarette smokers and ENDS users, the effects of three concentrations of protonated nicotine aerosolized at two different power settings. Forty-five participants (22 cigarette smokers and 23 ENDS users) completed some or all of six sessions that varied by liquid nicotine concentration (10, 15, or 30 mg/ml protonated nicotine) and device power (15 or 30 W). Participants took 10 puffs from each product and then used each product for 90 min ad libitum. Plasma nicotine concentration, subjective effects, and puff topography were measured. Results showed increases in plasma nicotine concentration in all conditions, with greater plasma nicotine increases in higher watt, higher nicotine concentration conditions, as well as greater nicotine delivery for ENDS users compared to cigarette smokers. For puff topography, puff duration and volume decreased as nicotine concentration and power increased, and ENDS users took longer and larger puffs than cigarette smokers. Participants rated the higher watt, higher nicotine concentration conditions as harsher and with more throat hit. Overall, these results suggest that device characteristics and liquid constituents interact to influence users' plasma nicotine delivery and should be considered together when regulating ENDS. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

E-cigarette Solvent Ratio and Device Power Influence Ambient Air Particulate Matter.

OBJECTIVES: Electronic cigarette (ECIG)-generated aerosol contains particulate matter with a diameter less than 2.5 microns (PM2.5). Particles of this size may be injurious to the health of those who inhale them. Few studies have assessed the relationship between ECIG aerosol PM2.5 and ECIG liquid ingredients or ECIG device power. METHODS: Two studies were conducted in which participants generated aerosols with ECIGs: in one, ECIG liquids contained various vegetable glycerin/propylene glycol ratios and in the other, ECIG devices varied by electrical power output. RESULTS: Results indicate that, in general, PM2.5 increases as the ratio of vegetable glycerin to propylene glycol increases, or as device power increases. CONCLUSIONS: Regulating ECIG PM2.5 emissions to protect non-users requires an understanding of all the factors that influence these emissions.

Brain imaging of cannabinoid type I (CB1 ) receptors in women with cannabis use disorder and male and female healthy controls.

Cannabis effects are predominantly mediated by pharmacological actions on cannabinoid type 1 (CB1 ) receptors. Prior positron emission tomography (PET) studies in individuals who use cannabis included almost exclusively males. PET studies in females are needed because there are sex differences in cannabis effects, progression to cannabis use disorder (CUD), and withdrawal symptom severity. Females with CUD (N = 10) completed two double-blind cannabis smoking sessions (Session 1: placebo; Session 2: active), and acute cannabis effects were assessed. After Session 2, participants underwent 3 days of monitored cannabis abstinence; mood, craving, and withdrawal symptoms were assessed and a PET scan (radiotracer: [11 C]OMAR) followed. [11 C]OMAR Distribution volume (VT ) from these participants was compared with VT of age/BMI-similar female non-users of cannabis ("healthy controls"; N = 10). VT was also compared between female and male healthy controls (N = 7). Females with CUD displayed significantly lower VT than female healthy controls in specific brain regions (hippocampus, amygdala, cingulate, and insula). Amygdala VT was negatively correlated with mood changes (anger/hostility) during abstinence, but VT was not correlated with other withdrawal symptoms or cannabis effects. Among healthy controls, females had significantly higher VT than males in all brain regions examined. Chronic cannabis use appears to foster downregulation of CB1 receptors in women, as observed previously in men, and there are inherent sex differences in CB1 availability. Future studies should elucidate the time course of CB1 downregulation among females who use cannabis and examine the relation between CB1 availability and cannabis effects among other populations (e.g., infrequent users; medicinal users).

Acute effects of JUUL and IQOS in cigarette smokers.

BACKGROUND: JUUL is an electronic cigarette that aerosolises a nicotine-containing liquid, while IQOS heats tobacco to produce an aerosol. Both are marketed to smokers, but their effects have seldom been examined in this population. METHODS: Eighteen cigarette smokers (13 men) with no JUUL or IQOS experience completed a within-subject, laboratory study assessing nicotine delivery and subjective effects after controlled (10 puffs, ~30 s interpuff interval) and ad libitum (90 min) use of JUUL, IQOS or own-brand (OB) cigarettes. RESULTS: JUUL increased mean plasma nicotine concentration significantly from 2.2 (SD=0.7) ng/mL to 9.8 (4.9) ng/mL after 10 puffs and to 11.5 (9.3) ng/mL after ad libitum use. IQOS increased mean plasma nicotine significantly from 2.1 (0.2) ng/mL to 12.7 (6.2) ng/mL after 10 puffs and to 11.3 (8.0) ng/mL after ad libitum use. OB increased mean plasma nicotine significantly from 2.1 (0.2) ng/mL to 20.4 (11.4) ng/mL after 10 puffs and to 21.0 (10.2) ng/mL after ad libitum use. Mean OB plasma nicotine concentration was significantly higher than JUUL and IQOS. OB increased expired carbon monoxide concentration, but IQOS and JUUL did not. 'Craving a cigarette/nicotine' and 'Urges to smoke' were reduced significantly for all products following the directed bout. CONCLUSIONS: Among smokers, JUUL and IQOS delivered less nicotine than cigarettes. Also, in this sample, IQOS and OB reduced abstinence symptoms more effectively than JUUL. Additional work with experienced JUUL and IQOS users is needed, as their nicotine delivery profiles and subjective experiences may differ.

Variable Voltage, Tank-Style ENDS Do Not Always Deliver Nicotine.

OBJECTIVE: This study's objective was to characterize the nicotine delivery profile of a variable voltage, tank-style electronic nicotine delivery system (ENDS). METHODS: Ten cigarette smokers (8 men, 2 women) completed this within-subject study assessing effects of 2 device power settings (15 W, 45 W) and 3 liquid nicotine concentrations (0, 3, and 6 mg/ml) using a tank-style ENDS. Participants completed one directed (10 puffs) and one ad libitum use period for each condition, with blood sampled throughout. RESULTS: Plasma nicotine concentration did not increase significantly at 15 W regardless of liquid nicotine concentration. At 45 W, mean plasma nicotine increased (not significantly compared to 0 mg/ml) from 2.24 ng/ml (SD=0.2) at baseline to 3.4 ng/ml (SD=0.6) in the 3 mg/ml condition. In the 6 mg/ml, 45 W condition, mean plasma nicotine increased significantly (compared to 0 mg/ml) from 2.0 ng/ml (SD=0) at baseline to 5.96 ng/ml (SD=1.3) after 10 puffs. In general, puff duration and volume decreased as device power and nicotine concentration increased. CONCLUSIONS: Despite using a variable wattage, tank-style device, nicotine delivery was minimal. These results, when combined with results from other studies using tank-style devices, highlight ENDS performance heterogeneity. Regulation may play a role in standardizing ENDS nicotine delivery.