13-Week smoke inhalation study of glycerin and propylene glycol

[Afteraffex]

Titre du document / Document title

Toxicologic evaluation of humectants added to cigarette tobacco: 13-Week smoke inhalation study of glycerin and propylene glycol in Fischer 344 ratsAuteur(s) / Author(s)

HECK J. Daniel ; GAWORSKI Charles L. ; RAJENDRAN Narayanan ; MORRISSEY Robert L. ; Résumé / Abstract

Glycerin (CAS no. 56-81-5) and propylene glycol (CAS no. 57-55-6) are commonly used as humectant ingredients in manufactured cigarettes to control and maintain the moisture content of the cut tobacco filler. The potentialof these added humectants to affect the toxicity of cigarette smoke was investigated in a subchronic nose-only smoke inhalation study in rats. Filtered test cigarettes were prepared from an American-style tobacco blend containing either glycerin added at 5.1% w/w tobacco, propylene glycol at 2.2% w/w tobacco, or combinations of these humectants totaling 2.3%, 3.9%, and 7.2% w/w tobacco. Other groups of animals were exposed similarly to the smoke of reference cigarettes without added humectants, or to filtered air (sham control). Smoke exposures were conducted for 1 h/day, 5 days/wk for 13 wk, at target smoke particulate concentrations of 350 mg/m3. All smoke-exposed groups had equivalent increases in blood carboxyhemoglobin, serum nicotine, and serum cotinine relative to the air controls. Smoke-associated reductions in body weights and occasional increases in heart and lung weights were generally similar among the various exposure conditions at necropsy. Increases in serum alkaline phosphatase and decreases in serum glucose and cholesterol were observed among smoke-exposed females relative to air controls. However, no significant differences in these parameters were evident between the humectant-containing and reference cigarette smoke exposure groups. Assessments of respiration conducted after 3, 6, 9, and 12 wk of smoke exposure indicated an initial smoke-related but not humectant-related decrease in respiratory rate, tidal volume, and minute volume during the first 20 min of each smoke exposure. Respiratory-tract histopathology was consistent across sexes and smoke groups, comprising (1) diffuse and focal alveolar pigmented macrophages and chronic interstitial inflammation in the lung, (2) laryngeal epithelial hyperplasia, squamous metaplasia, and scab formation, and (3) epithelial hyperplasia in the anterior nose. Smoke-related histopathology resolved substantially during a 6-wk postexposure recovery period. Addition of the tested humectants to cigarettes, singly or in combination, had no meaningful effect on the site, occurrence, or severity of respiratory-tract changes or on the measured indices of pulmonary function. It was concluded that the addition of glycerin and propylene glycol to cigarettes does not significantly affect the biological activity of inhaled cigarette smoke in this rat model.Revue / Journal Title

Inhalation toxicology ISSN 0895-8378 Source / Source

2002, vol. 14, no11, pp. 1135-1152 [18 page(s) (article)]Langue / Language

Anglais
Editeur / Publisher

Taylor & Francis, Philadelphia, PA, ETATS-UNIS (1989) (Revue)
Localisation / Location

INIST-CNRS, Cote INIST : 21573, 35400010545862.0040

Nº notice refdoc (ud4) : 14021772

[Afteraffex]

It was concluded that the addition of glycerin and propylene glycol to cigarettes does not significantly affect the biological activity of inhaled cigarette smoke in this rat model.Revue / Journal Title

[Afteraffex]

I just though this was interesting enough to share, i've found quite a few articles on the use of vg and pg as an inhalant additive in analogue cigarettes.

[Kent C]

Thanks for posting.

[paladinx]

Does anyone care about the percentages of PG that was being actually used?

wasn't there a much better study done that bob posted about exposure of PG on chimps?

[Sun Vaporer]

Great find and thanks for the post---Sun

[jtwh20]

Awesome - Thanks for Posting

[OutWest]

Does anyone care about the percentages of PG that was being actually used?

wasn't there a much better study done that bob posted about exposure of PG on chimps?

in the 1942 Time magazine article it mentioned the research on chimps and prolonged exposure to PG vapor.