Detection of tamoxifen metabolites by GC-MSD.

Tamoxifen is an antiestrogen used in the adjuvant endocrine therapy of early breast cancer and malignant breast disorders. It is also used in women with anovulatory infertility caused by its stimulating effect on the secretion of the pituitary gonadotrophic hormones. In males it could increase the endogenous production of androgens. Because of these properties tamoxifen may be misused in some sports to treat the androgens suppression caused by the extensive abuse of anabolic androgenic steroids. A method for identification and confirmation of tamoxifen metabolites is described. Hydroxymetoxytamoxifen is detected in urine by gas chromatography and mass spectrometry in a selective ion monitoring method followed by the routine postrun in the screening of anabolic steroids. Once the hydroxymetoxytamoxifen is detected, confirmation of reported metabolites could be performed with a 5973 mass selective detector in the scan mode after solid-phase extraction by cationic exchange. This study also reports an excretion profile for a single dose of tamoxifen equivalent to 40 mg administrated orally to two males volunteers.

Gas chromatography/mass spectrometric study of non-commercial C-4-substituted 1,4-dihydropyridines and their oxidized derivatives.

A gas chromatography/mass spectrometry (GC/MS) method for the qualitative and quantitative determination of the calcium-channel antagonists C-4-substituted 1,4-dihydropyridines, and their corresponding N-ethyl derivatives, is presented. Also, the electrochemical oxidation and the reactivity of the compounds with alkyl radicals derived from 2,2'-azobis-(2-amidinopropane) were monitored by GC/MS. Mass spectral fragmentation patterns for the C-4-substituted 1,4-dihydropy-ridine parent drugs were significantly different from those of their oxidation products, generated either by electrochemical oxidation or by reaction with alkyl radicals. However, for N-ethyl-1,4-dihydropyridine compounds it was not possible to detect the final products (pyridinium salts) using these experimental conditions.

Simultaneous determination of melatonin and pyridoxine in tablets by gas chromatography-mass spectrometry.

A gas chromatographic-mass spectrometric (GC-MS) method for the qualitative and quantitative determination of melatonin plus pyridoxine commercial tablets is described. Melatonin and pyridoxine were simultaneously determined by GC-MS after extraction from ground tablets with methanol and derivatization with N-methyl-N-N-trimethlylsilyltrifluoroacetamide (MSTFA). The mass chromatograms were generated using 232 m/z ion for melatonin and 280 m/z ion for pyridoxine, respectively. Splitless injection offers good reproducibility with a standard deviation of 2%. The developed method was applied to analyze the melatonin and pyridoxine content from two different tablet formulations. Also, recovery, detection and quantification limits are reported.

Drugs in prehistory: chemical analysis of ancient human hair.

Concern about drug abuse in modern populations has led to the development of specific methods for identification of cocaine, opiates and cannabis in human hair. Drug use in prehistory can provide indirect evidence of interpopulational contact and social stratification. This paper reports drug evaluation in nineteen ancient hair samples from archaeological sites in northern Chile. Each sample was tested for the presence of traces of cocaine, opiates and cannabis, in order to establish a standard methodology for studies of drug use among prehistoric groups. Although results are negative, this absence of evidence could be due to two main causes: (1) the individuals evaluated did not use any drugs, which does not mean that other members of their cultural group did, or (2) the wide range of known drugs studied did not consider some group specific drugs, derived from local or imported plants, thus meaning that a greater drug range must be tested. In any case, our study confirms that drug testing in prehistoric samples is viable. However, in order to determine what kind of substances were used in prehistoric times new patterns that incorporate all drugs which are not part of the western pharmacopeia must be created. Finally, a methodology for the study of drug use among prehistoric groups using ancient hair samples is described.