E-cigarettes an evidence update A report commissioned by Public Health England
3nOaxpIe4
3nOaxpIe4
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E-<strong>cigarettes</strong>: <strong>an</strong> <strong>evidence</strong> <strong>update</strong>3) Nicotine concentration <strong>an</strong>d chemical composition of e-liquidY<strong>an</strong> & D’Ruiz (2014) examined nicotine delivery from Blu cigalike EC with differinglevels of nicotine (2.4% <strong>an</strong>d 1.6%), glycerin/propylene glycol (75% glycerin <strong>an</strong>d 50%glycerin/20% propylene glycol), <strong>an</strong>d flavours (classic tobacco <strong>an</strong>d menthol)[129].Particip<strong>an</strong>ts (23 smokers) were r<strong>an</strong>domized to 5 different EC conditions <strong>an</strong>d smoking aregular cigarette in a cross over design. They were given 7 days to familiarize with ECuse, <strong>an</strong>d then abstain from all nicotine products for 36 hours prior to test days. On testdays particip<strong>an</strong>ts were asked to take 50 x 5 second puffs on EC at 30 sec intervals (inthe cigarette arm they smoked 1 cigarette with usual puff duration at 30 sec intervals).After the controlled puffing testing ppts were allowed 60 minutes of ad lib use.Peak plasma nicotine concentrations were reached sooner for <strong>cigarettes</strong> (5 minutes)th<strong>an</strong> for EC (30 minutes). During the 30 minutes controlled puffing phase, within ECconditions the highest Cmax was seen with the 2.4% nicotine, 50% glycerin/20% PG(18.09 ng/ml, SD=6.47 ng/ml). The lowest Cmax was observed in the 1.6% nicotine,75% glycerine (10.34 ng/ml SD=3.70 ng/ml). The Cmax associated with smoking oneconventional cigarette was 15.84 ng/ml (SD = 8.64 ng/ml). At the end of the ad libperiod, the highest Cmax was seen with the conventional cigarette (29.23 ng/ml SD =10.86 ng/ml), followed <strong>by</strong> the 2.4% nicotine, 50% glycerin/20% PG EC (22.42 ng/ml; SD= 7.65ng/ml). The glycerine/PG mix resulted in better nicotine delivery th<strong>an</strong> the 75%glycerine solution, which was confirmed in the bench top tests that measured nicotinecontent in vapour using the C<strong>an</strong>adi<strong>an</strong> Intense regimen. The high nicotine content invapour is a likely consequence of the lower boiling point of PG (187.6 degrees Celsius)compared with glycerine (290 degrees Celsius).4) Type of EC deviceAlthough m<strong>an</strong>y vapers start off with using a cigalike EC experienced vapers are morelikely to be using t<strong>an</strong>k systems or variable power EC. One of the reasons for thisobservation is that the t<strong>an</strong>k systems <strong>an</strong>d variable power ECs deliver nicotine morenicotine to the user.Farsalinos et al., (2014) examined plasma nicotine levels in experienced vapers (n=23)who used a cigalike (V2 with cartomiser) <strong>an</strong>d a new generation (EVIC set at 9 watts withEVOD atomizer) EC with st<strong>an</strong>dardized flavour <strong>an</strong>d nicotine concentration (18mg/ml) in across-over design[129]. Particip<strong>an</strong>ts’ abstained from EC use for at least 8 hours beforecompleting a bout of 10 puffs over 5 minutes followed <strong>by</strong> one hour of ad lib use. Use ofthe cigalike EC was associated with <strong>an</strong> increase in blood nicotine from 2.80 ng/ml atbaseline, to 4.87 ng/ml at 5 minutes <strong>an</strong>d 15.75 ng/ml at the end of ad lib use.Signific<strong>an</strong>tly greater increases were observed with use of the new generation EC from2.46 ng/ml to 6.59 ng/ml to 23.47 ng/ml at baseline, 5 minutes <strong>an</strong>d at the end of the adlib period.109
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