Abstract: AIM: To investigate the method of mea-suring the content of nicotine in the blood of rats exposed in burning cigarette smoke or nicotine fog.METHODS: The potassium cyanide-barbituric acid method for deter-mining cotinine, the metabolite of nicotine, in the urine of rats was evaluated.The nicotine solutions of various concentrations were infused to rats through tail vein with stable rate for one hour to make the standard curve of nic-otine in the blood of rats.Then, the total urine of 60 h was collected and the content of cotinine in the urine was measured as the output of nicotine from rats.The standard curve was established between the standard control of nic-otine and the output of cotinine.The ratswere exposed to the box filled with burning cigarette smoke or nicotine fog for 1 h, the total urine of 60 h was collected and the cont-ent of cotinine in the urine was measured, and the ab-sorbed content of cotinine in the blood of rats was calcu-lated according to standard curve equation, respectively. RESULTS: The standard control of nicotine and the out-put of nicotine in rat had a well linear relation, and the absorbed content of nicotine in the blood of rats could be estimated according to the output of the cotinine.CONCLUSION: The potassium cyanide-barbituric acid meth-od for determining cotinine in rat urine is consistent with the pharmacokinetical research.

Key words: cigarette, nicotine, cotinine, safety evaluation, exposure, measure