Glutathione-stabilized Fe3 O4 nanoparticles as the sorbent for magnetic solid-phase extraction of diazepam and sertraline from urine samples through quantitation via high-performance liquid chromatography.

The synthesis and application of glutathione-coated magnetic nanocomposite were introduced with the purpose of developing a stable, cheap, operationally convenient, simple, fast, sensitive, and selective device for the microextraction of diazepam and sertraline for the first time. The prepared glutathione@Fe3 O4 nanocomposite was used as the sorbent in the form of magnetic solid-phase extraction. Afterward, the extracted analytes were desorbed by organic solvent and analyzed by high-performance liquid chromatography-ultraviolet detection. Several influential variables such as desorption time, desorption volume, sample pH, extraction time, and sorbent amount were screened through Plackett-Burman design and then optimized via Box-Behnken design. The obtained results showed that the above-mentioned method enjoys a good linear range (0.2-500 µg/L) with the coefficient of determination higher than 0.9927, low limits of determination (0.07-0.24 µg/L), acceptable limits of quantification (0.22-0.93 µg/L), good enrichment factors (128 and 153), and good spiking recoveries (95-105%) for diazepam and sertraline under the obtained optimized condition. Analyzing the real samples results in the confirmation of the presented method and it can be applied for the analysis of various organic compounds in biological samples.

A silica fiber coated with a ZnO-graphene oxide nanocomposite with high specific surface for use in solid phase microextraction of the antiepileptic drugs diazepam and oxazepam.

A novel ZnO-graphene oxide nanocomposite was prepared and is shown to be a viable coating on fused silica fibers for use in solid phase microextraction (SPME) of diazepam and oxazepam from urine, this followed by thermal desorption and gas chromatographic quantitation using a flame ionization detector. A central composite design was used to optimize extraction time, salt percentage, sample pH and desorption time. Limits of detection are 0.5 µg·L-1 for diazepam and 1.0 µg·L-1 for oxazepam. Repeatability and reproducibility for one fiber (n = 4), expressed as the relative standard deviation at a concentration of 50 µg·L-1, are 8.3 and 11.3% for diazepam, and 6.7 and 10.1% for oxazepam. The fiber-to-fiber reproducibility is <17.6%. The calibration plots are linear in the 5.0-1000 µg·L-1 diazepam concentration range, and from 1.0-1000 µg·L-1 in case of oxazepam. The fiber for SPME has high chemical and thermal stability (even at 280 °C) after 50 extractions, and does not suffer from a reduction in the sorption capacity. Graphical abstract A hydrothermal method was introduced for preparation of ZnO- GO nano composite on a fused silica fiber as solid phase microextraction with high mechanical, chemical stability and long service life.

Preparation of a novel sorptive stir bar based on vinylpyrrolidone-ethylene glycol dimethacrylate monolithic polymer for the simultaneous extraction of diazepam and nordazepam from human plasma.

A new monolithic coating based on vinylpyrrolidone-ethylene glycol dimethacrylate polymer was introduced for stir bar sorptive extraction. The polymerization step was performed using different contents of monomer, cross-linker and porogenic solvent, and the best formulation was selected. The quality of the prepared vinylpyrrolidone-ethylene glycol dimethacrylate stir bars was satisfactory, demonstrating good repeatability within batch (relative standard deviation < 3.5%) and acceptable reproducibility between batches (relative standard deviation < 6.0%). The prepared stir bar was utilized in combination with ultrasound-assisted liquid desorption, followed by high-performance liquid chromatography with ultraviolet detection for the simultaneous determination of diazepam and nordazepam in human plasma samples. To optimize the extraction step, a three-level, four-factor, three-block Box-Behnken design was applied. Under the optimum conditions, the analytical performance of the proposed method displayed excellent linear dynamic ranges for diazepam (36-1200 ng/mL) and nordazepam (25-1200 ng/mL), with correlation coefficients of 0.9986 and 0.9968 and detection limits of 12 and 10 ng/mL, respectively. The intra- and interday recovery ranged from 93 to 106%, and the relative standard deviations were less than 6%. Finally, the proposed method was successfully applied to the analysis of diazepam and nordazepam at their therapeutic levels in human plasma. The novelty of this study is the improved polarity of the stir bar coating and its application for the simultaneous extraction of diazepam and its active metabolite, nordazepam in human plasma sample. The method was more rapid than previously reported stir bar sorptive extraction techniques based on monolithic coatings, and exhibited lower detection limits in comparison with similar methods for the determination of diazepam and nordazepam in biological fluids.

Removal of trace organic chemical contaminants by a membrane bioreactor.

Emerging wastewater treatment processes such as membrane bioreactors (MBRs) have attracted a significant amount of interest internationally due to their ability to produce high quality effluent suitable for water recycling. It is therefore important that their efficiency in removing hazardous trace organic contaminants be assessed. Accordingly, this study investigated the removal of trace organic chemical contaminants through a full-scale, package MBR in New South Wales, Australia. This study was unique in the context of MBR research because it characterised the removal of 48 trace organic chemical contaminants, which included steroidal hormones, xenoestrogens, pesticides, caffeine, pharmaceuticals and personal care products (PPCPs). Results showed that the removal of most trace organic chemical contaminants through the MBR was high (above 90%). However, amitriptyline, carbamazepine, diazepam, diclofenac, fluoxetine, gemfibrozil, omeprazole, sulphamethoxazole and trimethoprim were only partially removed through the MBR with the removal efficiencies of 24-68%. These are potential indicators for assessing MBR performance as these chemicals are usually sensitive to changes in the treatment systems. The trace organic chemical contaminants detected in the MBR permeate were 1 to 6 orders of magnitude lower than guideline values reported in the Australian Guidelines for Water Recycling. The outcomes of this study enhanced our understanding of the levels and removal of trace organic contaminants by MBRs.

Design of packed-fiber solid-phase extraction device for analysis of the drug and its metabolite in plasma.

A mini-column packed with 1 mg electrospun polystyrene nanofibers (about 200 approximately 400 nm in diameter) was designed for simple, fast extraction of drugs, diazepam and its major metabolite, N-desmethyldiazepam for the analysis of them in human and dog plasma. Ttrezodone was selected as internal standard. The drugs adsorbed on the solid phase could be desorpted with 50 microl of the methanol and then monitored by liquid chromatography coupled to an ultraviolet detector. Parameters influencing the extraction efficiency such as fiber packing amount, eluted solvent, and pH of the sample were decided. The time for the pretreatment of 0.5 ml plasma sample was less than 10 min. The detection limits of diazepam and N-desmethyldiazepam in plasma could be as low as 1 microg/L. The intra- and inter-day precision, calculated from quality control (QC) samples, was less than 9.1%. The method was evaluated by its application in determination of dog plasma samples from three beagles after a single dose oral of diazepam. The technique was validated by comparison with conventional plasma analysis. It was observed that the mini-column offers improved limits of detection and reduced sample preparation time as compared to conventional method. For its simplicity and sensitivity, the method may be used in therapeutic drug monitoring and pharmacology study.

Determination of 17alpha-ethynylestradiol, carbamazepine, diazepam, simvastatin, and oxybenzone in fish livers.

A method using liquid chromatography/tandem mass spectrometry (LC/MS/MS) was developed for the determination of 17alpha-ethynylestradiol in fish liver; a second method using LC/MS was developed for the determination of carbamazepine, diazepam, simvastatin, and oxybenzone in fish liver. The fish liver samples were extracted and cleaned up by using liquid-liquid extraction and solid-phase extraction before the extracts were analyzed by LC/MS or LC/MS/MS with electrospray negative and positive ionization. Recoveries of the 5 target compounds from spiked catfish liver ranged from 72 +/- 2 to 100 +/- 3%. Limits of quantification for the 5 compounds were between 4.2 and 12.3 ng/g (wet weight). Ten turbot (Pleuronichthys verticalis) liver samples were analyzed; levels of 17alpha-ethynylestradiol, carbamazepine, simvastatin, and oxybenzone were below the detection limits. Diazepam was detected in all 10 fish liver samples at concentrations ranging from 23 to 110 ng/g (wet weight).

Fate of pharmaceutical and personal care products (PPCPs) during anaerobic digestion of sewage sludge.

The behaviour of 13 pharmaceutical and personal care products (PPCPs) has been studied during anaerobic digestion of sewage sludge: two musks (Galaxolide and Tonalide), one tranquilliser (Diazepam), one anti-epileptic (Carbamazepine), three anti-phlogistics (Ibuprofen, Naproxen and Diclofenac), two antibiotics (Sulfamethoxazole and Roxithromycin), one X-ray contrast medium (Iopromide) and three oestrogens (Estrone, 17beta-oestradiol and 17alpha-ethinyloestradiol). Two parallel processes have been carried out, one in mesophilic range (37 degrees C) and the other in thermophilic range (55 degrees C). The influence of temperature and sludge retention time (SRT) has been analysed. Among the substances considered, the higher removal efficiencies were achieved for the antibiotics, natural oestrogens, musks and Naproxen. For the other compounds, the values ranged between 20% and 60%, except for Carbamazepine, which showed no elimination. The removal of oestrogens, Diazepam and Diclofenac occurred after sludge adaptation. In general, no influence of SRT and temperature on PPCPs removal was observed. Considering the difficulty of obtaining reliable PPCPs concentrations, especially those corresponding to the fractions sorbed onto sludge, a methodology to validate the experimental data has been developed and successfully applied.

Continuous purification of active pharmaceutical ingredients utilizing polymer membrane surface wettability.

Continuous processing of pharmaceuticals opens opportunities for continuous separation based on wettability of polymer membranes. Dual use of hydrophobic and hydrophilic membranes realize in-line liquid-liquid extraction in the synthesis of four essential APIs. A secondary membrane with opposite wetting characteristics proves critical to phase separation of aqueous-organic reaction streams.

Development of an ultra-high-performance liquid chromatography coupled to high-resolution quadrupole-Orbitrap mass spectrometry method for the rapid detection and confirmation of illegal adulterated sedative-hypnotics in dietary supplements.

A novel method using ultra-high performance liquid chromatography coupled to hybrid quadrupole-Orbitrap high-resolution mass spectrometry (UHPLC-Q-Orbitrap) was developed and validated for the simultaneous screening, identification and quantification of sedative-hypnotics in dietary supplements. Chromatographic conditions were optimised and a full data-dependent MS(2) scan (MS/dd-MS(2)) in positive and negative ion mode was used. A single injection was sufficient to perform the simultaneous screening and identification/quantification of samples. The response showed a good linear relationship with analyte concentrations over wide ranges (e.g., 1.0-1000 ng g(-1) for diazepam) with all the determination coefficients (r(2)) > 0.9985. The method was validated, obtaining accuracy (intra- and inter-day) in the range of 94.5-105.3% and precision (intra- and inter-day) in the range of 0.4-8.9%, respectively. The detection limits (LODs) were in the range of 0.3-1.0 ng g(-1) for different analytes. Recoveries were performed and ranged from 74.1% to 90.2%, while all matrix effects were over the range of 85.4-93.6%. Finally, this method was used to detect sedative-hypnotics in commercial dietary supplements. Of a total of 45 batches of dietary supplements, only three batches were found to be positive samples with concentrations of diazepam, clonazepam and alprazolam at high levels (≥ 8.22 mg g(-1)).

Detection of desmethyldiazepam and diazepam in brain of different species and plants.

Recent data suggest that desmethyldiazepam (DD), a major metabolite of several benzodiazepines (BZD), might be of natural origin. Therefore we tried to quantify DD and diazepam (D) in animals during maturation (e.g. hen, chicken, eggs), in brain of species at different evolutionary stages e.g. salmon, frog, monitor/reptile, rat, cat, dog, deer, bovine) including newborn and adult humans. Since low concentrations of DD (range 0.01-0.04 ng/g wet wt) and D (range 0.005-0.02 ng/g) could be measured in different species by sensitive and specific mass spectrometry (GC-MS), we analysed also several plants (e.g. maize corn, lentils, potatoes, soybeans, rice, mushrooms). Again, DD and D could be detected in low amounts (0.005-0.05 ng/g) in some plant products. This would suggest that DD and D might be of natural origin and incorporated via the foodchain into the animal and human body. The biological role or clinical relevance of these intriguing findings need still to be elucidated.

Clinical significance of methohexital, meperidine, and diazepam in breast milk.

Concentrations in breast milk of medications used during general anesthesia were measured to determine whether interruption of breast-feeding was indicated. Breast milk and maternal blood samples were obtained from nine women undergoing tubal sterilization under general anesthesia. Concentrations of methohexital, meperidine, diazepam, and nordiazepam were determined for each sample by gas chromatography. Methohexital levels declined rapidly after the first hour and were undetectable at 24 hours. Meperidine was present in both milk and blood during the recovery period but not at 24 hours. Infant-exposure indices for methohexital were less than 1% and ranged from 1.2% to 3.5% for meperidine. The maximum doses of methohexital and meperidine to an infant, in a 100 mL feeding 1 hour after induction of anesthesia were estimated to be 0.04 mg and 0.06 mg, respectively. Diazepam and nordiazepam were not detectable in any sample of milk or blood. The maximum possible infant-exposure index for diazepam would be 3%. The amounts of methohexital, meperidine and diazepam excreted into breast milk do not warrant interruption of breast-feeding.

Coupling device for desorption of drugs from solid-phase extraction-pipette tips and on-line gas chromatographic analysis.

Solid-phase extraction-pipette tips were used for micro solid-phase extraction of lidocaine and diazepam. Off-line desorption was done after in-vial collection for reference purposes, whereas with on-line desorption the eluate was directly introduced in the gas chromatograph. With both methods the total eluate (100 microl) was introduced into the GC system, which was equipped with a programmed-temperature vaporiser (PTV) for large volume injection. For on-line desorption a laboratory-made coupling device was developed to connect the pipette tips with the injector of the PTV. The coupling device was applied successfully since no leakage occurred at the connection of the coupling device and the pipette tip. No significant differences in recovery of lidocaine and diazepam and in presence of impurities were observed between chromatograms obtained with either off-line or on-line desorption. Preliminary experiments with standard solutions showed recoveries of about 75% for a concentration level of 1 microg/ml. The system seems particularly suitable for high-throughput analysis.

[Comparison of solid phase and liquid-liquid extraction of diazepam and nitrazepam]. / Diazepam és nitrazepam szilárd fázisú és folyadék-folyadék extrakciójának összehasonlítása.

We have developed a new extraction technique for nitrazepam and diazepam using Samplex C-18 column. The blood-extractions containing diazepam and nitrazepam were diluted with acetonitrile-water 7:3 eluent. Diazepam and nitrazepam were isolated using liquid-liquid extraction technique. The blood-extracts were diluted with chloroform-ethanol 1:1 and they were evaluated by using OPLC method. Evaluation was done by TLC-scanner (Shimadzu). The efficiency and sensitivity of the methods have been compared.

[The preservability of sibazon breakdown products in the cadavers of experimental animals]. / Sokhraniaemost' produktov raspada sibazona v trupakh éksperimental'nykh zhivotnykh.

Cibasone degradation products were measured in corpses of 15 cats poisoned with cibasone in a dose of 750 mg/kg. Cibasone was assessed by semiquantitative method on Silufol UV-254 plates from the content of the main degradation product 3-methylamino-5-chloro-benzophenone (MCB) in parallel with label in the benzene system. MCB was detectable in cadaveric material and in the container bottom panel for up to 7 years 8 months and in soft tissue until their complete putrefactive destruction. MCB concentrations were the highest in the stomach, thin intestine, and liver and the lowest in the muscles and bones. The main product of elenium (chlozepide) degradation product 2-amino-chloro-benzophenone (ACB) was detected along with MCB in a year and up to 4 years 7 months after burial, although elenium was not injected. Degradation products were identified by electron spectroscopy in UV and visible bands of the spectrum: lambda max = 238 and 410 nm for MCB and 238 and 390 nm for ACB. ACB is the product of MCB degradation-dimethylation in putrefactive degradation of tissues. Ethanol extraction of degradation products detects MCB and ACB 7 years 8 months postmortem.

Dynamic high performance liquid chromatography on chiral stationary phases. Low temperature separation of the interconverting enantiomers of diazepam, flunitrazepam, prazepam and tetrazepam.

Diazepam and the structurally related 1,4-benzodiazepin-2-ones tetrazepam, prazepam and flunitrazepam are chiral molecules because they adopt a ground state conformation featuring a non-planar seven membered ring devoid of any reflection-symmetry element. The two conformational enantiomers of this class of benzodiazepines interconvert rapidly at room temperature by a simple ring flipping process. Low temperature HPLC on the Whelk-O1 chiral stationary phase allowed us to separate the conformational enantiomers of diazepam and of the related 1,4-benzodiazepin-2-ones, under conditions where the interconversion rate is sufficiently low, compared to the chromatographic separation rate. Diazepam, tetrazepam and prazepam showed temperature dependent dynamic HPLC profiles with interconversion plateaus indicative of on-column enantiomer interconversion (enantiomerization) in the temperature range between -10 °C and -35 °C, whereas for flunitrazepam on-column interconversion was observed at temperatures between -40 °C and -66 °C. Simulation of exchange-deformed HPLC profiles using a computer program based on the stochastic model yielded the apparent rate constants for the on-column enantiomerization and the corresponding free energy activation barriers. At -20 °C the enantiomerization barriers, ΔG(≠), for diazepam, prazepam and tetrazepam were determined to be in the range 17.6-18.7 kcal/mol. At -55 °C ΔG(≠) for flunitrazepam was determined to be in the 15.6-15.7 kcal/mol range. The experimental dynamic chromatograms and the corresponding interconversion barriers reported in this paper call for a reinterpretation of previously published results on the HPLC behavior of diazepam on chiral stationary phases.

Drug facilitated sexual assault: detection and stability of benzodiazepines in spiked drinks using gas chromatography-mass spectrometry.

Benzodiazepines are detected in a significant number of drug facilitated sexual assaults (DFSA). Whilst blood and urine from the victim are routinely analysed, due to the delay in reporting DFSA cases and the short half lives of most of these drugs in blood and urine, drug detection in such samples is problematic. Consideration of the drinks involved and analysis for drugs may start to address this. Here we have reconstructed the 'spiking' of three benzodiazepines (diazepam, flunitrazepam and temazepam) into five drinks, an alcopop (flavoured alcoholic drink), a beer, a white wine, a spirit, and a fruit based non-alcoholic drink (J2O) chosen as representative of those drinks commonly used by women in 16-24 year old age group. Using a validated GC-MS method for the simultaneous detection of these drugs in the drinks we have studied the storage stability of the benzodiazepines under two different storage conditions, uncontrolled room temperature and refrigerator (4°C) over a 25 day period. All drugs could be detected in all beverages over this time period. Diazepam was found to be stable in all of the beverages, except the J2O, under both storage conditions. Flunitrazepam and temazepam were found not to be stable but were detectable (97% loss of temazepam and 39% loss of flunitrazepam from J2O). The recommendations from this study are that there should be a policy change and that drinks thought to be involved in DFSA cases should be collected and analysed wherever possible to support other evidence types.

The redox behaviour of diazepam (Valium®) using a disposable screen-printed sensor and its determination in drinks using a novel adsorptive stripping voltammetric assay.

In this study we investigated the possibility of applying disposable electrochemical screen-printed carbon sensors for the rapid identification and quantitative determination of diazepam in beverages. This was achieved utilising a previously unreported oxidation peak. The origin of this peak was investigated further by cyclic voltammetry and gas chromatography/mass spectroscopy. At pH 6 the voltammetric behaviour of this oxidation process was found to involve adsorption of the drug allowing for the development of an adsorptive stripping voltammetric assay. Experimental conditions were then optimised for the determination of diazepam in a beverage sample using a medium exchange technique. It was shown that no elaborate extraction procedures were required as the calibration plots obtained in the absence and presence of the beverage were very similar.

Evaluation of diazepam-molecularly imprinted microspheres for the separation of diazepam and its main metabolite from body fluid samples.

Molecularly imprinted microspheres (MIMs) for the drug diazepam and its main metabolite (nordiazepam) were prepared and used to separate the two species from urine and serum samples via molecularly imprinted solid-phase extraction. The specific binding capacity for diazepam was determined to be 1.97 mg/g, resulting in an imprinting factor of 5.8. The MIMs exhibit highly selective binding affinity for tricyclic benzodiazepines. Water-acetonitrile-acetone mixtures were used as the washing solvent and resulted in complete baseline separation, with a recovery of >87% for diazepam and of 88% for nordiazepam. The limits of detection are 21.5 and 24.5 ng/mL, respectively.

ß-Cyclodextrin conjugated magnetic nanoparticles for diazepam removal from blood.

ß-CD conjugated magnetic nanoparticles that serve as a hemoadsorbent for diazepam removal are fabricated. The diazepam is arrested by the conjugated ß-CD and then the adsorbed diazepam is efficiently removed by an external magnetic field. These particles have potential applications in hemoperfusion or separation of other toxins and drugs.