Safety evaluation of toothpaste containing chloroform. II. Long term studies in rats

Area of Science:

• Toxicology
• Oral Health
• Pharmacology

Background:

• Chloroform is a chemical compound with various industrial applications.
• Its presence in toothpaste bases necessitates toxicological evaluation for consumer safety.
• Previous studies indicated potential effects on serum enzymes and hematological parameters.

Purpose of the Study:

• To assess the long-term oral toxicity of chloroform when incorporated into a toothpaste base.
• To evaluate the carcinogenic potential and other adverse effects of chronic chloroform exposure.
• To determine the safety profile of chloroform in oral hygiene products.

Main Methods:

• Conducted a 13-week rangefinding toxicity study.
• Performed two long-term oral toxicity studies in Sprague-Dawley rats (80 weeks exposure).
• Administered chloroform (60 mg/kg/d) in toothpaste base or vehicle control via gavage, 6 days/week.

Main Results:

• Higher doses in the rangefinding study showed serum enzyme and hematological changes.
• Long-term studies revealed improved survival in chloroform-treated rats despite high incidences of non-neoplastic respiratory and renal diseases in both groups.
• No statistically significant increase in tumor incidence (overall, liver, or kidney) was observed; however, a non-significant trend towards more malignant mammary tumors in treated females was noted. Plasma cholinesterase decreased in female rats.

Conclusions:

• Chloroform in toothpaste base did not demonstrate significant treatment-related toxicity or carcinogenicity in long-term rat studies.
• Observed effects, such as decreased plasma cholinesterase in females and non-neoplastic diseases, warrant consideration but do not indicate severe toxicity.
• The findings suggest a low risk associated with the oral use of chloroform in toothpaste at the tested levels.