Glycerin and the 'Acrolein problem' anyone vaping VG read this

[rlorange]

Agreed guys we are all on the same side and I am reassured that you have all researched this well.

I started this on another thread and there I said that I believe that acrolein is a possibility but probably not happening because atomizers just dont get hot enough.

If it wasnt for the Acrolein concern then I would be all for VG but with an atomizer at 250 degress and acrolein formation starting at 280 this is a bit close for my comfort.

Thanks for showing an interest in this subject everyone and I do believe that I will look into the Acrolien reaction in more detail when I get back into the Chem library at uni.

 

[Phalse]

Wow, after reading those reports its pretty obvious PG+nic+flavor is much better than smoking analogs.

IF VG does not have an acrolein problem with our atomizers, I feel its even safer than PG, which could possibly irritate your lungs after prolonged usage and have a slight (much smaller than analogs) chance of liver/kidney damage.

This is excluding people who have a different allergic reaction to PG. They are in a different group.

 

[rlorange]

I wonder how much PG we are all ingesting from sources other than e-smoking does anybody know any studies to point to?

I'm guessing 1ml per day of vaping would deposit maybe 3/4 of that, the rest being exhaled. (Assuming one doesn't hold it in excessivly). So that's 750mg.

ow the studies I have heard causing kidney toxicity involved multiple injected doses of 800+ milligrams within a day resulting in a total exposure of 129g before toxicity was experienced.

Remember just because something is toxic in a high dose doesnt mean that it is 'very slightly' toxic in a very small dose. Almost everything we ingest except a few poisons have a 'toxic threshold' below which it casues zero harm. The question is where is that toxic threshold with PG, and is say 1.5g daily, the max for a hard-core vaper, well below this?

Nicotine has a lethal dose of 36mg-60mg! yet in small doses we know is no worse than caffiene, which incedently has a toxic dose of between 2 and 5 grams or 20-50 coffees!

 

[rlorange]

Christopher MM, Eckfeldt JH, Eaton JW.

Department of Veterinary Pathobiology, University of Minnesota, St. Paul.

Propylene glycol (1,2-propanediol) is a solvent in numerous pharmaceuticals and a major preservative and source of carbohydrates in processed foods. In mammals, propylene glycol is metabolized similar to ethanol, proceeding via hepatic alcohol and aldehyde dehydrogenases to lactate, which can then enter gluconeogenesis. We observed that cats ingesting 1.6 gm of propylene glycol/kg body weight/day developed increased anion gap. To investigate this further, we measured D- and L-lactate concentrations in these cats; we also measured D-lactate in cats ingesting high doses of propylene glycol (8.0 gm/kg). While L-lactate actually decreased throughout the 35-day course of propylene glycol feeding, D-lactate levels were significantly increased on a dose-dependent basis and correlated positively with anion gap. In cats ingesting the high dose of propylene glycol, D-lactate concentrations were as high as 7 mmol/liter, levels associated with encephalopathy in humans. Indeed, this group of cats developed depression and ataxia, consistent with intoxication by D-lactate. These findings are significant not only for animals ingesting diets which contain propylene glycol, but for humans who receive propylene glycol-containing medications.

PMID: 2296157 [PubMed - indexed for MEDLINE]

Related Articles

* Unusual D-lactic acid acidosis from propylene glycol metabolism in overdose. [J Toxicol Clin Toxicol. 2004]
* Contribution of propylene glycol-induced Heinz body formation to anemia in cats. [J Am Vet Med Assoc. 1989]
* Propylene glycol-induced Heinz body formation and D-lactic acidosis in cats. [Prog Clin Biol Res. 1989]
* ReviewRecognition, treatment, and prevention of propylene glycol toxicity. [Semin Dial. 2007]
* ReviewD-lactic acidosis. A review of clinical presentation, biochemical features, and pathophysiologic mechanisms. [Medicine (Baltimore). 1998]

» See Reviews... | » See All...
Recent Activity
Wish I could read the rest!

 

[rlorange]

7.2 Toxicity

7.2.1 Human data

7.2.1.1 Adults

The estimated acceptable daily
intake is 25 mg/kg (17th Report of the Joint
FAO/WHO Expert Committee on Food Additives,
1974). Single oral doses of 1.5 g/kg (used
in the treatment of glaucoma) caused
dizziness (Goldsmith, 1978). Lactic acidosis
and coma with hyperosmolality were seen in an
elderly patient with a propylene glycol serum
concentration of 910 mg/dl after IV
administration of nitroglycerin dissolved in
propylene glycol (Demey et al,
1984).

There is more about PG here.


Very funny because under 'Inhalation' it says: Not relevant! Obviously never heard of smoke machines and e-smoking.

25mg per kg per day is the max safe dose. I assume safe does not include long term liver or kidney harm. So thats 2.2g for me. I estimate I'm absorbing 1g max from my vaping and thats only the ocassional heavy day. Oh and I don't use many PG based creams, hair products or medicines. Liquid Tylenol caps can have more than 500mg of PG per dose!!

 

[rlorange]

Good PG link

Propylene Glycol excerpted from NTP-CERHR expert panel on the reproductive and developmental toxicity of propylene glycol - The Center For The Evaluation Of Risks To Human Reproduction (CERHR) NTP-CERHR-PG-03 May 2003

If I was living in Japan I would be ingesting 6 grams of the stuff per day!!!!

 

[rlorange]

Sorry that was WAY OFF!! LOL 43mg per day.... Hmmm much less. I need time to digest all of this info Aaarrgghh!

 

[Phalse]

I think the body does filter those things out but I still wouldnt say 0 harm. There must be some stress on our biology, like kidneys.
It may be almost 0 harm but still must place some kind of stress on the body filtering anything above what we normally take in?

Thats just my opinion, I do love biology but I got a C and decided it would be tuff to take that series and make something of it. Probably would have gotten a C- in the next class.

 

[Phalse]

So what does it seem to do when you get to the toxic oral dose.
(I don't think e-cigs give even close to enough to be toxic like the studies where they feed it to cats and such)

Dizzyness, depression in cats, Coma in elderly :L), whats it do mess up your brain chem in some way?

 

[Phalse]

So if you intake 43 mg from vaping, yet the acceptable safe dose daily limit is 25mg, thats already over the safe dose, not even adding what you get from other sources.

If you intake 1 gram from vaping thats 1000mg and WAY WAY over the safe dose daily limit for PG.

 

[deewal]

Just remember guys, we're all on the same side

I'm not so sure about that.
If you are so worried then carry on smoking your Tobacco. They Kill
for sure and has been pointed out several times contain acrolein and hundreds of other very harmful toxins that E-Cigs do not.

I don't think posting a "scare topic" on the main General E-Smoking Discussion page is very helpful to new members. Infiltrators looking for damaging misinformation on the other hand will love it.
This belongs in the Health, Safety and E-Smoking section where it has been discussed many,many times.

Information on Atomisers and their temperatures and technical issues are to be found in Tips&Tricks, Modders Forum and DIY e-liquid.Also there is a very good thread E-liquid lab/toxicology reports in the Health, Safety forum.
You will find a vast amount of information in these forums written by Very clever Technical people who have been studying and even building E-Cigs for quite sometime.

 

[Phalse]

Yeah, you probably shouldnt have posted "VG problem" in the title unless you were 100% sure there was one.
It seems you were only very confident there was a problem but not 100% positive.

Since the Boiling point temp of 290 is confirmed for VG but the production of acrolein at 280 is NOT confirmed yet, you could have changed the title and intro to be less "scary"

 

[strayling]

25mg per kg per day is the max safe dose. I assume safe does not include long term liver or kidney harm. So thats 2.2g for me.

Sorry that was WAY OFF!! LOL 43mg per day

How do you get that?

For me it's 65kg x 25mg/kg/day = 1625mg/day

I think you were right the first time.

 

[Phalse]

If you are so worried then carry on smoking your Tobacco. They Kill
for sure and has been pointed out several times contain acrolein and hundreds of other very harmful toxins that E-Cigs do not.

Well yes this is sort of accurate but a little off.

See when you smoke an analog cig you smoke a large amount of tobacco which releases a lot of different chemicals, you do smoke a lot of cigs but still the actual acrolein amount is small. Their problem is the tar from carbon in the tobacco plant + nicotine AND acrolein in small amount PLUS 100's of other chemicals in addition to acrolein.

Since VG makes up our e-cig base that we smoke and the carbon molecule in the VG doesn not combust to create dioxides, we only have to worry about our base + nic + flavoring. Yes our base we use to smoke is a very small amount, yes the acrolein from VG would only be made if the atomizer got too hot (malfunction) BUT our concern is a massive release of acrolein from a single drop of VG being combusted.

The acrolein production point of VG being before its BP 290 could be true, We dont know yet.
VG may only produce acrolein if combusted (malfuction in atomizer),
We dont know this either.

Thats the 2 questions we are trying to answer, it is NOT answered in the other threads of this forum.

 

[deewal]

Thats the 2 questions we are trying to answer, it is NOT answered in the other threads of this forum.

Well i've just pointed out Where you should ask these questions and it's not in General E-Smoking Discussion.

 

[Phalse]

it took us 15 pages of discussion to figure it out, stop telling us what to post.

I now officially dislike you.

I was going to post something nice like, hey that guy was right about the forum moving fast with new threads, but we shouldnt tell people what to do and just have a positive discussion.

BUT NOW I'm convinced you have 0 to add to this dicussion, everything you posted just talks about old points 6 pages back, like you have not read the dicussion and really figured out where we are in our understanding of PG and VG.
YOU simply post things, like some other posters that have nothing positive to add, dont advance the discussion and pretty much annoy or slam the other posters in subtle ways.

This is lame man, why are you acting like this, EVERY single post of yours is a complaint, question about their skills, or you didnt even read and understand the discussion AND you complain about wrong forum!

YOU personally questioned my integrity now your messing with this guy who is obviously smarter than you or I am, even more when it comes to chemistry.

This is a discussion thread, General discussion is fine for this thread.

 

[rlorange]

Wow guys chill out!

Firstly. I stand by the fact that Acrolein starts forming at 280 degrees celcius. This I have confirmed from 3 online sources and my University library online database of organic chemistry reactions.

Acrolein is a thermal decomposition-dehydration reaction which occurs spontaneously with high temperatures in glycerin above 280 degrees C.

It is my opinion that this is a major worry, otherwise I would not have worded the title of this thread as such. If you disagree fine and post your diagreement but don't accuse me of scaremongering because that is not what I am about. If I didn't study chemistry and just stumbled on this Acrolein Problem online then yeah... I could be alarmist. My concern does not come from ignorance it comes from the science and nobody seems to dispute this (except maybe the 280 degree figure).

As I mentioned there is a threthhold below which a substance can be said to have zero harm. Even a substance that is toxic in higher doses. I do not know what this is for PG but I am assuming it is higher than the ammout I am absorbing by vaping. Based on the WHO figures this is 25mg per kg of body weight. You the math for me this would be vaping more than 3ml per day (assuming 3/4 is absorbed).

The effects of PG can be subdivided.

1. Acute toxicity to the Central Nervous System leading to coma and death. This effect only happens with massive doses and is the exact same mechanism and Alcohol Poisoning. PG is less than 1/2 as potent as Alcohol so we are talking more than 100 Grams.

2. Acute Renal Hepatic toxixity. This does not happen to all and just like alcohol will affect people already weakened.

3. Chronic low dose exposure. Acidiosis. Unique to PG lactic acid build up can occur but again most healthy people can clear the lactic acid fromed as PG is broken down in doses much higher that we vape. Ballpark up to 10 grams per day will not produce acidosis in most people. If you drink lot of alcohol or other variables will vary the dose of course.

NOTE: PG is NOT toxic at small doses to the body any more that Alcohol is (chemically they are very similar as far as the body is concerned). Furthermore it breakdown products are not toxic (except lactic acid in large doses) In fact the breakdown products are all parts of the Citric Acid Metabolic Cycle, common to all complex life on this planet.

 

[Phalse]

Good stuff. Thanks!

 

[kinabaloo]

According to this paper, there might be a problem. I will quote 2 paragraphs and add bold:

"It [Glycerine] boils under 760 mm. pressure at 290° C. with slight decomposition, but under reduced pressure it distils unchanged, its b.p. at 50 mm. pressure being 210° C. and at 12.5 mm. 179.5° C. It is not volatile at ordinary temperatures, but on concentration of a solution of it in water at ordinary pressures glycerol volatilises with the water vapours at a temperature of about 160° C, corresponding to a concentration of about 70 per cent.

When strongly heated it rapidly loses water with the formation of acrolein, leaving a residue of poly glycerols, chiefly diglycerol C6H1405."

Source: The Distillation Of Glycerine

The second quoted sentence is a litle confusing but might imply that use of VG would be safer if the water quanity it is mixed with is higher. However, there is still the issue of 'strongly heated' condition. No conclusions can be drawn from this as it is difficult to see how it relates exactly to what happens in the atomizer and I simply put it out for others to consider. If acrolein is formed, some portion of it will quickly polymerise and then burn on the coil leaving residue of, ultimately, carbon. Does the atomiser gunk resemble burnt plastic rather than soot (shiny rather than dull, for example)?

When I heat VG mixed with water (roughly 50/50 mix), i see the water evaporate first. Then the VG evaporates and no residue is left that I can see. This is slow heating. Terraphon heated VG quickly with a blowtorch and did get a residue and bad smell (this is in the thread about Wire Wool). How careful he was not to set light to the VG I am not sure.

 

[Phalse]

I didnt see the bodyweight per day part of the daily safe dose of PG.

I see now the safe dose is 25mg for each 1 kg body weight per day.