On-line immunoaffinity extraction and HPLC analysis of flunitrazepam and its main metabolites in serum.

A sensitive, simple, and rapid method for the determination of flunitrazepam and its major metabolites (7-aminoflunitrazepam, 7-acetamidoflunitrazepam, and norflunitrazepam) in serum and plasma is presented. The on-line procedure uses an immobilized, highly reusable antibody against benzodiazepines for selective extraction from serum followed by analysis by high-performance liquid chromatography with ultraviolet detection. This reliable method provides a limit of detection of 1 ng/mL serum, and results are obtained in less than 40 min.

Simultaneous extraction of selected benzodiazepines and benzodiazepine-glucuronides from urine by immunoadsorption.

A rapid and selective cleanup procedure based on immunoadsorption is described for the simultaneous extraction of diazepam and its free or glucuronidated metabolites nordiazepam, temazepam, and oxazepam from urine. The method can also be used for the extraction of lorazepam and lorazepam-glucuronide. Because the samples do not have to be hydrolyzed before extraction, valuable information is preserved. With the exception of lorazepam-glucuronide, recoveries between 86 and 100% were obtained at spiking levels up to 200 ng of benzodiazepine or glucuronide per milliliter of urine. Using methanol/water (90:10, v/v) as an eluent, the immunoadsorber could be used at least 20 times. High-performance liquid chromatograms of urine samples from patients receiving low therapeutic dosages of diazepam or lorazepam are shown to demonstrate the high purity of the extracts.

Simple high-performance liquid chromatographic column-switching technique for the on-line immunoaffinity extraction and analysis of flunitrazepam and its main metabolites in urine.

A sensitive, simple and rapid method without sample pretreatment is presented for the simultaneous determination of flunitrazepam and its main metabolites (norflunitrazepam, 7-amino- and 7-acetamidoflunitrazepam) in urine. The single-step procedure is based on a column-switching technique which uses an immobilized antibody in an extraction column following concentration on a precolumn and separation on an analytical column. UV detection was performed at 254 nm. The reusability of the antibody exceeds 88 runs and a complete analysis was performed in less than 40 min. The method shows coefficients of variation below 9.9% and rates of recovery greater than 92% tested at the level of 50 ng/ml urine. The limit of detection was below 2 ng/ml urine for the four compounds.

Identification and determination of the two principal metabolites of minocycline in humans.

A chromatographic method has been developed for the quantification of minocycline in human serum and urine. The chromatographically determined concentration of minocycline correlated well with the microbiologically active concentration in serum. Two metabolites, 9-hydroxyminocycline and N-demethylated minocycline, could be isolated and identified as the principal metabolites of this tetracycline antibiotic. The structure of the 9-hydroxy compound was proved by nuclear magnetic resonance analysis for the first time. About 15% of the drug was actively converted in the body into a substance less microbiologically active than the parent compound and excreted in the urine within 96 h after the application.

[Dose-response relationships between blood alcohol concentrations and cognitive potentials (visual P300) in man]. / Dosiswirkungsbeziehungen zwischen Blutalkoholkonzentrationen und kognitiven Potentialen (visuelles P300) beim Menschen.

20 healthy male subjects with a mean age of 24 +/- 2.7 years were intravenously administered a mean total dose of ethanol of 1.33 +/- 0.04 g ethanol/kg body weight using a perfusor device. The ethanol kinetic resulted in a "rising phase" of 90.2 +/- 0.9 min. in average. The PFP300 parameter in this phase of acute alcohol intoxication showed the following changes: Along with the increasing blood alcohol level the N250- and PFP300a-latencies of both the A- and B-potentials are progressively prolonged and the ascending PFP300-amplitudes are progressively reduced. The N250-latency of the B-potentials is shown to be the most sensitive parameter of the PFP300-complex already changing at a blood alcohol concentration (= b.a.c.) of 0.59 +/- 0.11% with a mean linear prolongation of 2.5 ms per 0.1 g ethanol/kg body weight. This prolongation reflects the increasing disability of the subjects to discriminate between task-relevant and task-irrelevant stimuli at b.c.a.-levels much below that being presently permitted for driving in the Federal Republic of Germany.

[Deaths resulting from combined action of alcohol and drug intake (author's transl)]. / Todesfälle durch kombinierte Wirkung von Alkohol und Medikamenten

11 cases of rapid central death following combination of sublethal doses of alcohol and sedativa are presented with case-history, histology, alcohol-concentrations and toxicological findings.