Analysis of certain tranquilizers in biological fluids

Analytical methods for determination of benzodiazepines. A short review

Benzodiazepines (BDZs) are generally commonly used as anxiolytic and/or hypnotic drugs as a ligand of the GABAA-benzodiazepine receptor. Moreover, some of benzodiazepines are widely used as an anti-depressive and sedative drugs, and also as anti-epileptic drugs and in some cases can be useful as an adjunct treatment in refractory epilepsies or anti-alcoholic therapy. High-performance liquid chromatography (HPLC) methods, thin-layer chromatography (TLC) methods, gas chromatography (GC) methods, capillary electrophoresis (CE) methods and some of spectrophotometric and spectrofluorometric methods were developed and have been extensively applied to the analysis of number of benzodiazepine derivative drugs (BDZs) providing reliable and accurate results. The available chemical methods for the determination of BDZs in biological materials and pharmaceutical formulations are reviewed in this work.

Benzodiazepines: sample preparation and HPLC methods for their determination in biological samples

Benzodiazepines (BDZs) belong to a group of substances known for their sedative, antidepressive, muscle relaxant, tranquilizer, hypnotic and anticonvulsant properties. Their determination in biological fluids is essential in clinical assays as well as in forensics and toxicological studies. Researchers focus on the development of rapid, accurate, precise and sensitive methods for the determination of BDZs and their metabolites. A large number of analytical methods using different techniques have been reported, but none can be considered as the method of choice. BDZs are usually present at trace levels (microgram or nanogram per milliliter) in a complex biological matrix and the potentially interfering compounds must be isolated by various extraction techniques before analysis. An extended and comprehensive review is presented herein, focusing on sample preparation (pretreatment and extraction) and HPLC conditions applied by different authors. These methods enable bioanalysts to achieve detection limits down to 1-2 ng/ml using UV/diode array detection, readily available in most laboratories, and better than 1 ng/ml using electron capture detection, which is lower than that obtained using a nitrogen phosphorus detector. MS interfaced with electrospray ionization offered a similar sensitivity, while negative chemical ionization MS or sonic spray ionization MS provided sensitivity down to 0.1 ng/ml.

Voltammetric analysis of drugs

A review on the voltammetric analysis of drugs is presented. The review includes a summary of the rules that must be considered for drug analysis and a survey of the use of voltammetry for drug analysis in the period from 1998 till 2002.

Analysis of Phenothiazine and Its Derivatives Using LC/Electrochemistry/MS and LC/Electrochemistry/Fluorescence

The on-line electrochemical conversion of phenothiazine and its derivatives after liquid chromatographic separation has been studied by mass spectrometry and fluorescence spectroscopy. In an electrochemical cell consisting of porous glassy carbon, the phenothiazines are readily converted to oxidized products, which can be detected by on-line fluorescence spectroscopy and mass spectrometry. The method allows rapid investigations on the electrochemical oxidation pathways, as demonstrated for phenothiazine itself. The phenothiazine derivatives are transferred into their strongly fluorescent sulfoxides. Based on this reaction, an LC/electrochemistry/fluorescence method was developed that allows for limits of detection between 5 x 10(-9) and 4 x 10(-8) mol/L and limits of quantification between 2 x 10(-8) and 1 x 10(-7) mol/L for the individual phenothiazines. The linear ranges comprised three decades starting at the limit of quantification.