The hypothesis was formerly put forward that the main therapeutic action of cimetidine (the histamine H2-receptor antagonist marketed as Tagamet®) as well as some of its side effects might be mediated by its interactions with essential metal ions.

The authors describe the nicotine quantification in milk by GC - MS. In order to obtain a good chromatographic separation, the nicotine is previously separated by steam distillation. Quinoleine is used as internal standard. CV is lower than 5 per cent.

A method for the determination of nanogram amounts of Δ9-tetrahydrocannabinol (THC) in plasma and serum is described. THC was quantitatively isolated by solid-phase extraction after addition of an aqueous solution of urea and methanol to the sample. The extracts were analysed by high-performance liquid chromatography with electrochemical detection in the oxidizing mode. The detection limit of THC is ca. 100 pg for a signal-to-noise ratio of 3. With this method, levels of 2 ng/ml of THC in plasma can be measured.

A molecule sensitive to light, to variations in temperature and pH, guanoxabenz hydrochloride cannot be estimated in biological fluids according to classical technics. The authors propose an analytical method based, during the extraction phase, on the formation of a copper complex extractable in organic medium and in the true phase of measurement, on the transformation, by hydrochloric acid hydrolysis in dichloro-2-6-benzaldehyde, estimated by gas phase chromatography with detection by capture of electrons. The sensitivity and the specificity of the technic authorise its use in pharmacokinetic studies in man.