Toxicological evaluation of aerosols of a tobacco extract formulation and nicotine formulation in acute and short-term inhalation studies

Abstract

A formulation of tobacco extract containing 4% nicotine (TE) and similar nicotine formulation containing vehicle and 4% nicotine (NF) were evaluated using animal inhalation assays. Two 4-h inhalation exposures at 1 and 2 mg/L aerosol exposure concentrations, respectively, of the tobacco extract with 4% nicotine formulation showed that the LC₅₀ was greater than 2 mg/L, the maximum concentration tested. All inhalation exposures were conducted using the capillary aerosol generator (CAG). Increasing aerosol TPM concentrations (0, 10, 50, 200, 1000 mg/m³ TE and 0, 50, 200, 500, 1000 mg/m³ NF) were generated via the CAG and used to expose groups of male and female rats for 4-h per day for 14 days. In life monitors for potential effects included clinical observations, weekly body weights and food consumption. Post mortem evaluations included gross tissue findings, hematology, clinical chemistry, serum plasma and nicotine levels, absolute and normalized organ and tissue weights, and histopathology of target organs. Treatment-related changes were observed in body weights, hematology, clinical chemistry, organ weights and histopathological findings for TE at the 200 and 1000 mg/m³ exposure levels, and in the 500 and 1000 mg/m³ exposure groups for NF. Under the conditions of these studies, the no-observed-adverse-effect level in the rat was approximately 50 mg/m³ for the TE aerosol-exposed groups, and approximately 200 mg/m³ in the NF aerosol-exposed groups.

• Capillary aerosol generator
• inhalation
• nicotine
• tobacco extract

Acknowledgements

The authors wish to thank Drs David Kane, Ali Rostami, Greg Griscik and Tony Howell for their work in overcoming numerous technical problems related to test material formulation, device performance and reliability, and aerosol generation. Without their solutions we could not have performed the inhalation toxicity studies. The authors acknowledge the expert editorial assistance of Eileen Y. Ivasauskas of Accuwrit Inc and the scientific review and insights provided by Dr George Patskan.