The Nicotine Discrepancy

[kinabaloo]

Some musings on the lower than expected transfer of nicotine from e-liquid to bloodstream in comparison to smoking.

While a few do claim to be able to get a similar hit with an e-cig, for many this is not the case; something approaching the same effect only being possible by upping the nic strength beyond what the maths would suggest as equivalent.

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A typical cigarette gives about 1mg nic. This is the absorbed amount determined from testing, not what's in the cigarette.

A typical juice is 20mg/ml with 1ml equivalent to about 10 cigs, perhaps a little less. So potentially 2mg per cig equivalent.

Typical inhale hold would be about 50% exhaled (if hold the vapor for 10 seconds or longer one can retain most of the vapor). So we are about on par now - about 1mg expected to be absorbed.

But the tests show much lower figures, as low as 10%, although we have assumed that the e-cig and e-liquid combination should be an almost perfect delivery mechanism.

So how can this be explained?

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Because the nic in vapor comes dissolved in the base liquid (VG / PG) this will significantly slow down absorption; perhaps the tests didn't sufficiently take this into account. Could be part of the answer, but probably not the whole account.

Perhaps the reasoning that the nic in e-liquid is in an easily absorbable freebase form is not correct. I think unlikely, but possible. Furthermore, amalog smoke only has a freebase content in the 10% - 60% range. So if this part of the answer, the nature of the binding would be very significant; for example, perhaps glycols bind to the active group rendering the nic almost inactive.

Perhaps a fair proportion of the nic gets destroyed in the atomiser due to the fast heat up and nicotine's relatively poor heat stability (it might be a major contributor to heater coil deposit build up). Just my hypothesis at the moment; 50/50 if this really occurs; would be quite a startling discovery if found to be the case.

I can imagine that in the comparative tests that the volunteers did not inhale as deeply with the e-cig as with analogs. However, even allowing for a number of such possibilities bringing the numbers closer, there remains a sizable difference yet to be both adequately explained and proven. It's quite a fascinating area of investigation, and one that might, if that understanding could translate to practical steps to improve the efficiency of the e-cig delivery system, mark a significant step forward.

edit: I am aware that an overlapping issue surrounding the for some people less than equivalent satisfaction may well involve addition co-factors found in analogs, such as MAOIs. Yet distinct from that there is a nic discrepancy that is independent.

[DVap]

As far as the buildup on atomizers, I've been vaping just PG/VG/Nicotine for awhile for a very clean ultra-light taste, and I'm not seeing any significant buildup on the atomizer.

I'm thinking if the liquid were made hot enough by the atomizer to decompose nicotine, then glycerin breakdown to acrolein would be happening as well. That would be a hard to miss taste. It looks like I'm going to have to come up with an auto-vaping test after all.

The looming question seems to be, "If we vape 1 mL of 24 mg liquid, have we vaped 24 mg of nicotine?". Only by first discovering the answer to that question, can we safely proceed to the next set of questions.

[kinabaloo]

As far as the buildup on atomizers, I've been vaping just PG/VG/Nicotine for awhile for a very clean ultra-light taste, and I'm not seeing any significant buildup on the atomizer.

I'm thinking if the liquid were made hot enough by the atomizer to decompose nicotine, then glycerin breakdown to acrolein would be happening as well. That would be a hard to miss taste. It looks like I'm going to have to come up with an auto-vaping test after all.

The looming question seems to be, "If we vape 1 mL of 24 mg liquid, have we vaped 24 mg of nicotine?". Only by first discovering the answer to that question, can we safely proceed to the next set of questions.

It would be good news if a small fraction of VG, perhaps when with PG, does not decompose to a significant degree. What % VG would you say you've been using, and for roughly how long?

I'm imagining that nic would react/oxidise/combust rather than decompose; if anything.

[DVap]

Probably 25% VG.. five weeks in the same atomizer, several mL's per day. I give it a water rinse now and then, with some isopropyl alcohol to dry it out. Other than that, maintenance-free. My fiancee uses a Dekang flavored mix, and the vapor output on her atomizer has become poor with the same maintenance as my atomizer. I'm going to have to hit it with some solvents and an ultrasonic bath to get it behaving again.

[kinabaloo]

Probably 25% VG.. five weeks in the same atomizer, several mL's per day. I give it a water rinse now and then, with some isopropyl alcohol to dry it out. Other than that, maintenance-free. My fiancee uses a Dekang flavored mix, and the vapor output on her atomizer has become poor with the same maintenance as my atomizer. I'm going to have to hit it with some solvents and an ultrasonic bath to get it behaving again.

Interesting result. That's quite a substantial throughput.

If no luck with baths, consider the 'dry burn'.

[SmokeyJoe]

I'm not convinced by this. From memory a far more plausible reason for the addictive nature of nicotine in tobacco is due to a "coupling" effect between nicotine and other chemicals present in tobacco smoke.

The "hit" sensation from smoking a cigarette is likely either to be due to carbon monoxide (asphyxiation) or the effect of some of the other chemicals in the smoke (some of which are potent monoamine oxidase inhibitors - ie, old school antidepressants) - or both.

[kinabaloo]

I'm not convinced by this. From memory a far more plausible reason for the addictive nature of nicotine in tobacco is due to a "coupling" effect between nicotine and other chemicals present in tobacco smoke.

The "hit" sensation from smoking a cigarette is likely either to be due to carbon monoxide (asphyxiation) or the effect of some of the other chemicals in the smoke (some of which are potent monoamine oxidase inhibitors - ie, old school antidepressants) - or both.

That may well all be true.

But nevertheless there is a discrepancy between expected levels of nicotine and measured blood levels.

I'm not trying to account for the reduced 'buzz' as such, just the lower than expected nic level. It must be going somewhere; question is: where? That is, what happens to it?

[Moonflame]

I wonder if our bodies just process and get rid of it more effectively without all of the additional stuff in cigs that we're no longer taking in.

[kinabaloo]

I wonder if our bodies just process and get rid of it more effectively without all of the additional stuff in cigs that we're no longer taking in.

The vast majority will go first to the bloddstream. I don't see a way that any cofactors in smoke could assist in it staying in the bloodstream longer; but I guess it's possible. If it was a matter of more effective at reachng the brain it would lower blood levels if anything; but that would surly be a minor effect (?)

[Kurt]

It would be good news if a small fraction of VG, perhaps when with PG, does not decompose to a significant degree. What % VG would you say you've been using, and for roughly how long?

I'm imagining that nic would react/oxidise/combust rather than decompose; if anything.

VG decomposition to acrolein at atty temps has been analyzed by Cignot with their ECOpure juice, and there was no acrolein at all at 300 C. Good news, but given that acrolein is a strong lacramator (mucus membrane irritant), you would certainly know if you were vaping it. Even ng quantities would have a major effect. I myself am quite relieved by this since I much prefer VG over PG.

Of course, I don't know if there is more of a chance of forming it with higher voltage, and thus hotter attys.

Kurt