Cotinine, the main metabolite of nicotine, was administered intravenously to healthy male non-smoking volunteers in doses of 5, 10 and 20 mg, and orally in doses of 10 and 20 mg. Intravenous administration was characterized by a dose-independent half-life of 12.2 h, mean residence time of 15.9 h, total clearance of 3.64 l h-1 and a volume of distribution of 56.5 l. Renal clearance was 0.46 l h-1 and approximately 12.0% of the dose was excreted unchanged in the urine. The mean absorption time after oral dosing ranged between 1 and 3 h, the peak concentration was reached within 45 min and the mean elimination half-lives were 12.9 and 11.7 h, respectively, after the 10 and 20 mg doses. Systemic bioavailability ranged between 0.84 and 1.11 following 10 mg and between 0.97 and 1.03 following the 20 mg dose. Mean urinary recovery and renal clearance were almost identical with the values after iv administration.

A method was developed for the isolation and identification of phytosterols and fatty alcohols in jojoba oil. The method consists in the separation of these compounds from wax esters in the oil by means of an aluminum oxide column followed by further fractionation of the minor components by column chromatography on silica gel. The 4-demethylsterols, 4-methylsterols, triterpene alcohols (4,4-dimethylsterols), and fatty alcohols are identified by means of their gas chromatographic and mass spectrometric data. The present paper includes a method for the quantitation of the free sterols in jojoba oil. Keywords: Plant; alcohol; sterol; lipid; Simmondsia

Measurement of plasma cotinine, the major metabolite of nicotine, is usually done to determine nicotine-intake in smokers. Cotinine is used instead of nicotine because it has a much longer half-life than the mother substance and its plasma concentrations are therefore less dependent on the exact times of blood sampling. However, the linearity of the relationship between nicotine-intake and cotinine level in plasma has never been proven. Therefore cotinine was measured in 6 healthy volunteers infused over 4 days with several doses of nicotine i.v. up to 480 micrograms/kg/day. Cotinine concentrations in plasma were shown to be linearly and directly related to nicotine intake. The concentration of cotinine showed little variation during and for up to 2 h after the last dose of nicotine. Therefore, cotinine can be used as an epidemiological marker of nicotine intake if it is measured around the time of the last cigarette of the day.

Cotinine levels in blood, urine and cervical fluid of smokers and nonsmokers were analyzed by capillary-column gas chromatography. The sensitivity of this method appeared to be 100%. The specificity was lower (87.5% in blood, 25% in urine and 75% in cervical fluid). Nonsmokers exposed to smoke by others had low but detectable cotinine levels in the three body fluids. The highest cotinine levels in cervical fluid were detected during the proliferative phase of the cycle. Cotinine levels in cervical fluid and blood correlated well, but the correlation was less during the proliferation phase. Cotinine measurement in cervical fluid proves to be a reliable method to quantify exposure to tobacco smoke, even when induced by others.

A high-pressure liquid chromatographic method for the determination of diuron and its metabolites in human urine and blood is presented. The synthesis of different metabolites and of a suitable internal standard is described and the structure of the compounds is determined by mass spectrometry and nuclear magnetic resonance spectroscopy. The method is applied to an overdose case.