TOXICOLOGIC EVaLUaTION OF hUMECTaNTS aDDED TO CIGaRETTE TOBaCCO: 13-WEEK SMOKE INhaLaTION STUDY OF GLYCERIN aND PROPYLENE GLYCOL IN FISChER 344 RaTS

Introduction:
This text presents a toxicological evaluation of the potential effects of added humectants (glycerin and propylene glycol) in cigarettes on the toxicity of cigarette smoke. The study was conducted as a 13-week smoke inhalation study in rats to investigate the potential of these added humectants to affect cigarette smoke-induced responses.

Key Points:

* The study used Fischer 344 rats exposed to smoke from cigarettes with and without added humectants.
* Cigarettes with different levels of humectants were prepared, and the smoke was generated using a smoking machine.
* The smoke was delivered to the animals through a nose-only restraint tube to minimize smoke aging and rebreathing.
* The study measured several parameters, including blood carboxyhemoglobin, serum nicotine and cotinine, body weights, hematology and clinical chemistry, respiration, and organ weights.
* The study found that the addition of humectants did not significantly affect the measured indices of pulmonary function.
* Respiratory-tract histopathology was consistent across sexes and smoke groups, with no meaningful effect of humectant addition.
* Smoke-related histopathology resolved substantially during a 6-week postexposure recovery period.

Main Message:
The study concludes 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. Therefore, the use of these humectants in cigarettes is unlikely to pose additional health risks beyond those associated with cigarette smoking. however, it is important to note that this study was conducted in rats and that further research is needed to confirm these findings in humans.

heck, J. Daniel, Charles L. Gaworski, Narayanan Rajendran, and Robert L. Morrissey. “TOXICOLOGIC EVaLUaTION OF hUMECTaNTS aDDED TO CIGaRETTE TOBaCCO: 13-WEEK SMOKE INhaLaTION STUDY OF GLYCERIN aND PROPYLENE GLYCOL IN FISChER 344 RaTS.” Inhalation Toxicology 14, no. 11 (January 2002): 1135–52. https://doi.org/10.1080/08958370290084827.