Cotinine in an ultrafiltrate of saliva

Abstract

Background. We have developed a device for the simplified collection of a prepurified sample of saliva in the mouth.Method. The device is based on the principle of an osmotic pump and accumulates about 1.2 ml of an ultrafiltrate of saliva within 8 min. We have investigated the ultrafiltrate for its utility as a biological medium in the evaluation of cigarette smoking status.Results. (a) In 58 matched samples from 13 subjects, the correlation coefficient for the cotinine concentration in the saliva and the ultrafiltrate was 0.95; (b) in matched plasma and ultrafiltrate samples from 27 smokers, the correlation coefficient for the cotinine concentrations was 0.96 with plasma containing 1.2 times the ultrafiltrate mean; (c) in a nonsmoker, elevated cotinine levels could be detected in the ultrafiltrate more than 24 hr after smoking 2 cigarettes, and the pattern of rise and decrease reflected that in whole saliva; and (d) in a habitual smoker, the mean cotinine concentration in the ultrafiltrate was 157 ng/ml (SD +/- 25.7 ng/ml) during a period of smoking 15 cigarettes per day and dropped to a mean of 47 ng/ml (SD +/- 10.5) when smoking was reduced to 5 cigarettes per day; after cessation of smoking, detectable concentrations of cotinine persisted for up to 5 days.Conclusion. The device facilitated the aesthetic, noninvasive collection of a biological sample useful in the validation of smoking status.