VG liquid inhilitaion recomendations

[howiez]

I found this short article regarding the inhilation of glycerol, and the recommended maximum doses for adults.

Is there any long term safety data on the effect of inhaling glycerol, which has been added to the new inhaler Clenil Modulite?

This is the interesting part pertaining to VG e-juice:

In humans, the licensed use of Clenil Modulite permits a maximum of 8mg of glycerol inhaled in one day or 0.16mg/kg/day based on a 50kg adult. The toxicology of glycerol following administration by inhalation was investigated in an 13-week inhalation study of aerolised glycerol in rats10 using doses in rats equivalent to 20mg/kg/day and 76mg/kg/day in humans which is 125 and 475 times higher than the maximum dose delivered through Clenil Modulite. Additionally, the ACGIH (1996) has reported that bio-kinetic studies indicate that a 70kg adult should be able to metabolise and excrete over two grams of glycerol per eight hour work day.11 It is on this basis that the present threshold limit (TLV) for inhaled glycerol is set for that of respirable nuisance particulates.11 The doses used in the 13 week study were 16.5 and 61 times the TLV. Based upon the results of the 13 week inhalation toxicology results, the use of up to 1mg/puff of glycerol in Clenil Modulite is not considered to pose a risk to patients as stated in the Clenil Modulite SPC.1

My question is how to determine how many inhilations off of an ecig would constitute 8mg per day?

[howiez]

Ok, since no one seems to have any ideas, I'll give it a shot.. science guys feel free to jump in!

You can not directly corolate MG to ML ,as one is the weight of a solid, and one is the volume of a liquid...

However, if you take a 30 ML bottle of e-juice, assume its 90% VG, thats 27 ML of VG.

27 ML of water is approximitly 27,000 MG (1 gram per ml of water). If there are 19 drops of e-liquid per ml, and 3 puffs per drop, that means that each puff contains...

(27,000 / 19) / 3 = 473 MG per puff

This is assuming the weight of e-liquid is identical to the weight of water (which I am sure it is not)

Am I way off here with my numbers? My initial post reported a maximum of 8MG per 8 hours per adult. Does this mean that 1 puff of a VG based e-cig is 59X the maximum inhilation of VG in my original post?

Help me out here!

[Kurt]

howiez, thanks for sharing this! Something is not right here, though. one puff cannot be almost 0.5 grams. In your conversion, you are assuming 19 drops is in 27 mL, not 1 mL. After converting correctly, by your numbers, I get 17.5 mg per puff, much more in line with the 8 mg you cite.

Besides, the inhaler forces the puff deep into the lungs through pressurization, along with the directions of emptying the lungs first, then while inhaling squeeze the inhaler. In fact, it has been shown that with "normal" PVs, very little vapor actually gets into the lungs, since nic is far and away absorbed orally and in the throat and nose, with very little nic is absorbed in the lungs. So it seems the amount of lung-absorbed VG is even lower than 0.5 mg, by this logic.

BTW, that study you cite with the rats in a glycerol atmosphere stated that there was no damage to the lungs at the levels they used. I do not know where the 8 mg per puff value comes from in terms of toxicity. Maybe it is an arbitrary FDA value?

[Java_Az]

Not sure what % it is but you exhale a pretty good % of what you inhale. So that's going to be a factor too.

[howiez]

Ok, I get the numbers now, we are looking at 17.5mg/puff based on 3 puffs per drop, and 19 drops per ml. This is still troubling to me, as stated in the original that a 70kg adult should be able to metabolize > 2 Grams per 8 hour work day, which is > 1/4 Gram per hour, or 250 MG per hour. At the rate of 17.5mg/puff, you are looking at 14.2 puffs per hour recommended maximum. When I'm puffing on my e-cig, its often more then 14 puffs/hour.

I understand that a portion of the VG is unabsorbed, and returns out through exhilation, but in this study they did not take this into account, so I'd like to be safe and assume a 100% absorption rate rate.

[markarich159]

Glycerol is one of the most benign organic liquids known. It is hypo-allergenic, non-carcinogenic, non-teratogenic and non-mutagenic. Glycerol is the backbone of all mono-di-and tri-glyceride fatty acids(the main constituent in all animal and vegetable fats) and is metabolized quite easily by a process called Beta-oxidation. This process results in, ultimately, the production of CO2 and H2O and is a quite normal, common and natural catabolic process. The only patient population which may experience problems with metabolism of Glycerol would be diabetics owing to the anabolic hepatic pathway which can convert free Glycerol to glucose(but this would still not be an issue at the levels used in vaping)

The accepted LD50(lethal dose 50%) for glycerol has been quoted as up to 4000mg/kg/day-which for a 75kg adult would be 300,000mg or 300g. Given the specific gravity(density) of Glycerol is 1.26g/ml, that would be a LD50 of 238ml per day(WELL above anything we would see vaping). For more info try this source:

http://www.jetoc.or.jp/HP_SIDS/pdffiles/56-81-5.pdf