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Title: TOXICOLOGY STUDY NO. 85-XC-3929-04. THE 90-DAY DERMAL TOXICITY OF THE REPELLENT SS-220 IN RATS. NOVEMBER 2004.

Author
item HOUPT, J. - U.S.ARMY
item DEBBOUN, M. - U.S.ARMY
item MICHIE, M. - U.S.ARMY
item PAULUS, H. - U.S.ARMY
item THOMPSON, M. - U.S.ARMY
item LEE, R. - U.S.ARMY
item KLUN, J. - U.S.D.A.ARS

Submitted to: U.S. Army Center for Health Promotion and Preventative Medicine
Publication Type: Government Publication
Publication Acceptance Date: 8/1/2005
Publication Date: 10/3/2005
Citation: Houpt, J.T., Debboun, M., Michie, M.W., Paulus, H.I., Thompson, M.I., Lee, R.B., Klun, J.A. 2005. The 90-day dermal toxicity of the repellent ss-220 in rats. U.S. Army Center for Health Promotion and Preventative Medicine. Toxicology Study No. 85-XC-3929-04.

Interpretive Summary: Serious diseases such as West Nile Virus, Lyme Disease, malaria, dengue fever, yellow fever and typhus are transmitted to humans by blood-feeding ticks, mosquitoes and lice, and there is a needed to develop new compounds as protectants against these disease carriers. A new compound,SS-220, proved to effectively repel biting mosquitoes in human-volunteer bioassays where the compound was placed skin and allowed to remained there for 12 hours. The problem was that, although the assay identified SS-220 as good candidate insect repellent,it was not known what toxic effects might be encountered by long term dermal exposure to the compound. Toxicological studies reported here proved that the compound was nontoxic when test animals were exposed dermally to SS-220 for 90 days, and this has cleared the way for its further entomological evaluation using human subjects. This is an important step in the eventual development and EPA registration of the compound as a new repellent to protect humans against blood-feeding arthropods that carry disease.

Technical Abstract: The purpose of the study was to determine the systemic toxicity from dermal application of the candidate insect repellent SS-220 in rats. It was found in a 90-day dermal study that the SS-220 had no systemic toxicity in rats. Skin irritations were evident in all exposure groups of both sexes. Female rats were more susceptible to the dermal irritating effects of SS-220 than males. The cutaneous changes resolved following a seven week recovery period. Lower body weights were present in mid and high dose groups of both sexes at day 91. No significant differences in body weight were observed in the recovery groups after day 91. The No-observed Adverse Effect Level for subchronic dermal exposure to SS-220 for 90 days is 60 mg/kg/day.