Studies on a Simultaneous Analytical Method of Urinary Nicotine and Its Metabolites, and Their Half-Lives in Urine

Abstract

The objectives of this research were to improve and standardize a relatively easy, highly sensitive and highly accurate method of measuring nicotine, cotinine and trans-3'-hydroxycotinine in the urine of non-smokers exposed to environmental tobacco smoke (ETS) and to clarify the reliability of this method. Blinded studies using this analytical method were conducted in two universities. Standard solutions of nicotine, cotinine and trans-3'-hydroxycotinine were prepared at one university, divided in two parts and sent to another two universities for analyses by gas chromatography-mass spectrometry (GC/MS) without revealing the concentrations. It was found that the assay lower limit was at a level that could be used in passive smoking surveys and good results were obtained in crosschecks of samples of unknown concentration between the two universities. Since this method was considered to be useful for analyzing these urinary substances, ETS exposure experiments were performed in three universities using urinary nicotine, cotinine and trans-3'-hydroxycotinine as specific biomarkers of the urine. Non-smokers were exposed to ETS in an exposure room in each university. It was found that the nicotine concentrations in the urine of the subjects exposed to ETS reached a peak at about 2 hours after the end of exposure, which was somewhat later than that in active smokers. Because cotinine and trans-3'-hydroxycotinine in the urine are metabolites of nicotine, it was evident that the quantities were lower and the increasing rates were also less than that of nicotine. When the deceases in nicotine/ creatinine, cotinine/creatinine and trans-3'-hydroxycotinine/creatinine ratios in the urine were calculated using theoretical curves, the half-life times were calculated to be 13.9, 20.0 and 63.0 hours, respectively.

A Health Threat to Bystanders Living in the Homes of Smokers: How Smoke Toxins Deposited on Surfaces Can Cause Insulin Resistance

“…In the US alone, nearly 88 million nonsmokers ages 3 and older live in homes where they are exposed to sufficient levels of SHS+THS to produce significant blood levels of cotinine (a metabolite of nicotine) and tobacco-specific nitrosamine, carcinogens that result from the reaction of nicotine with nitrous acid in the environment [ 3 ]. These metabolites have been found to be present in the urine of infants and children living in the homes of smokers [ 4 – 6 ]. In a separate study, an association was found between on-set of insulin resistance and type 2 diabetes in adolescents that grew up in households where at least one parent smoked cigarettes [ 7 – 10 ].…”

Cigarette Smoke Toxins Deposited on Surfaces: Implications for Human Health

“…We chose to use nitrosamines to compare between humans and mice because the half-life of the nitrosamines (days) is much longer than that of cotinine (hours) and therefore makes the comparison between our well-controlled experiments and not-as-well-controlled human data collection more reliable [27], [28]. The intermittent exposure of children to cigarette smoke introduces uncertainty in cotinine data because the timing between the exposure and the urine collection for a study cannot be closely controlled.…”

Biologic Mechanisms of Environmental Tobacco Smoke in Children with Poorly Controlled Asthma: Results from a Multicenter Clinical Trial

“…Only 8.1% of the 160 children submitting urine for analysis had detectable cotinine (≥0.5 ng/mL). Although cotinine is the primary metabolite of nicotine, it has a half-life of 16 to 30 hours 23,24 and likely has limited sensitivity in the setting of intermittent exposure.…”