Salivary Cotinine ELISA Kit

(S)-Cotinine is a trace alkaloid found in tobacco plants and is the main metabolite of nicotine. Compared with nicotine (2-3 hours), its pharmacological half-life (15-19 hours) is longer and it is often used as a biomarker. Cotinine binds to nicotinic and muscarinic acetylcholine receptors with minimal receptor desensitization, exhibits antipsychotic-like properties in behavioral models, has neuroprotective properties in neurodegenerative disease models, and enhances attention during delayed matching. Studies have shown that high-frequency and long-term tobacco exposure is closely related to lung cancer, oral cancer, nasopharyngeal cancer, esophageal cancer, breast cancer, uterine cancer, colorectal cancer and other diseases. Reasonable and effective tobacco control and secondhand smoke exposure intervention are of great significance. Scientific measurement of tobacco exposure is the basis for the study of the correlation between tobacco exposure and health, the evaluation of tobacco control effects and the evaluation of secondhand smoke exposure intervention effects. Cotinine is one of the important biomarkers of tobacco exposure. It is the product of nicotine metabolic conversion by human cytochrome oxidase. Cotinine has a slow distribution rate in human tissues and a long half-life. It can reflect the human body's 3-4 days of environmental tobacco smoke (ETS) exposure and is an important indicator for measuring tobacco exposure. Therefore, determining the concentration of cotinine in biological samples is of great significance for assessing the dose and degree of human tobacco exposure.

Figure 1. Hair determination of nicotine and cotinine status.(Source: Inukai T, et al. 2018)

The concentration of cotinine can directly reflect the dose and degree of human tobacco exposure. It can be used to evaluate the health status, degree of passive smoking, living conditions and physiological characteristics of the human body. It has a variety of application scenarios, reflecting the value of measuring the cotinine concentration of biological samples. The application of cotinine mainly includes: 1. health index assessment, as an objective biological marker, cotinine reflects the exposure level of smoking and helps to understand the physical health of smokers. It is related to dyslipidemia, bone abnormalities, etc. It is a conventional measurement indicator for understanding the stress state of smoking; 2. passive smoking evaluation, passive smoking commonly known as secondhand smoke, refers to the mixed smoke formed by the tobacco smoke released from the burning end of cigarettes or other tobacco products and exhaled by smokers. It is associated with the risk of lung cancer in non-smokers. Through the detection of human cotinine, it can be used to evaluate ETS exposure, so as to timely and effectively control such pollution and reduce damage to the human body; 3. forensic toxicology analysis, biological samples retained at the scene of the case or on physical evidence may contain nicotine, drugs and drug components, and cotinine is one of the possible components. The inspection of cotinine in the sample can provide relevant information on the living and physiological characteristics of the person involved.

Cotinine that enters the human body exists in multiple parts and matrices. Understanding different sample types and their characteristics is conducive to the selection and processing of samples. There are many types of biological samples used for cotinine detection, including urine, blood, saliva, hair, etc., and the composition and properties of these samples are complex. Plasma/serum: Cotinine is converted into nicotine in the liver and released into the blood. Therefore, the cotinine content in the blood can best reflect the nicotine content absorbed by the human body from ETS, that is, it can most accurately reflect the human body's ETS exposure. Hair: Hair has an accumulation effect on cotinine. Therefore, measuring the cotinine content in hair samples can reflect the human body's long-term ETS exposure. Studies have confirmed that the cotinine content in hair is strongly correlated with an individual's smoking history. Urine: Urine samples are easy to collect and less invasive to the subjects. It is an ideal biological sample for research. By measuring the concentration of cotinine in urine, the dose and degree of human tobacco exposure can also be evaluated. Breast milk: Pregnant women are affected by smoking conditions, and breast milk is contaminated. Nicotine and cotinine can easily enter the baby's body through breast milk. The content of cotinine in breast milk can be used as an indicator for specific smoking cessation education and breastfeeding guidance for pregnant women who smoke. Saliva: Tobacco alkaloids are important chemical components in the saliva of smokers. Accurate determination of their content is of great significance for exploring the sensory perception mechanism of cigarette smoking; Hard tissue: Hard tissue is a tissue formed by biomineralization in the body (such as bones, teeth, etc.), which is a special substance between inorganic and organic matter. After smoking, cotinine will remain in the oral hard tissues. This can explore the distribution pattern and pathogenic effect of cotinine in the oral hard tissues of passive smoking, and evaluate the accumulation changes of cotinine in the oral hard tissues after stopping passive smoking; Toenails: Toenails are independent of melanin and grow slowly, growing about 0.1 cm per month. The content of tobacco alkaloids in toenails reflects the average risk exposure over 1 month. Therefore, toenails can not only be used as samples for cotinine detection, but also because they are independent of melanin and grow slowly, they can reflect the average exposure over more than one month, which is the advantage of their analysis compared with hair samples.

(S)-Cotinine
1-Methyl-5-(3-pyridyl)-2-pyrrolidinone