Validation of a novel, fully automated high throughput high-performance liquid chromatographic/tandem mass Spectrometric method for quantification of pantoprazole in human plasma

An automated high-throughput HPLC/MS/MS method was developed for the quantitative determination of pantoprazole in human plasma. Only 100 microL plasma was placed in 2.2 mL 96 deep-well plates, and both pantoprazole and omeprazole (IS) were extracted from human plasma by liquid-liquid extraction, using diethyl ether-dichloromethane (70:30, v/v) as the organic solvent. Robotic liquid-handling workstations were used for all liquid transfer and solution preparation steps and resulted in a short sample preparation time. After vortexing, centrifugation, and freezing, the supernatant organic solvent was evaporated and reconstituted in a small volume of reconstitution solution. Sample analysis was performed by utilizing the combination of RP-HPLC/MS/MS, with positive-ion electrospray ionization and multiple reaction monitoring detection. The chromatographic run time was set at 1.8 min with a flow rate of 0.6 mL/min on a Nucleosil octylsilyl (C8) analytical column. The method was proven to be sensitive, specific, accurate, and precise for the determination of pantoprazole in human plasma. The method was applied to a bioequivalence study after per os administration of a 40 mg pantoprazole gastric retentive tablet.     

Anamorsin is a [2Fe-2S] cluster-containing substrate of the Mia40-dependent mitochondrial protein trapping machinery

Human anamorsin was implicated in cytosolic iron-sulfur (Fe/S) protein biogenesis. Here, the structural and metal-binding properties of anamorsin and its interaction with Mia40, a well-known oxidoreductase involved in protein trapping in the mitochondrial intermembrane space (IMS), were characterized. We show that (1), anamorsin contains two structurally independent domains connected by an unfolded linker; (2), the C-terminal domain binds a [2Fe-2S] cluster through a previously unknown cysteine binding motif in Fe/S proteins; (3), Mia40 specifically introduces two disulfide bonds in a twin CX(2)C motif of the C-terminal domain; (4), anamorsin and Mia40 interact through an intermolecular disulfide-bonded intermediate; and (5), anamorsin is imported into mitochondria. Hence, anamorsin is the first identified Fe/S protein imported into the IMS, raising the possibility that it plays a role in cytosolic Fe/S cluster biogenesis also once trapped in the IMS.     

Comparative Study of a Series of 99mTc(CO)3 Mannosylated Dextran Derivatives for Sentinel Lymph Node Detection

Sentinel lymph node detection (SLND) is rapidly entering common practice in the management of patients with tumors. The introduction of mannose molecules to ^99mTc-labeled dextrans, so far, showed that the sentinel node could trap these agents due to their recognition by the mannose receptors of lymph node macrophages. The current study aimed to synthesize, characterize, and biologically evaluate a series of mannosylated dextran derivatives labeled with ^99mTc for potential use in SLND. The compounds were designed to have a dextran with a molecular weight of 10–500 kDa as a backbone, S-derivatized cysteines, efficient SNO chelators, and mannose moieties for binding to mannose receptors. They were successfully synthesized, thoroughly characterized using NMR techniques, and labeled with the fac-[^99mTc(CO)₃]⁺ synthon. Labeling with high yields and radiochemical purities was achieved with all derivatives. In vivo biodistribution and imaging studies demonstrated high uptake in the first lymph node and low uptakes in the following node and confirmed the ability to visualize the SLN. Among the compounds studied, ^99mTc-D75CM demonstrated the most attractive biological features, and in combination with the high radiochemical yield and stability of the compound, its further evaluation as a new radiopharmaceutical for sentinel lymph node detection was justified.     

Graphene‐coated cotton fibers as a sorbent for the extraction of multiclass pesticide residues from water and their determination by gas chromatography with mass spectrometry

A straightforward functionalization procedure is proposed for synthesizing a cotton‐supported graphene as an extraction material, which is effectively employed for the extraction of multiclass pesticides from environmental waters prior to their determination by gas chromatography with mass spectrometry. Different experimental parameters that affect the extraction efficiency, including pH of the extraction, stirring rate, extraction time, ionic strength, presence of humic acid, sample volume, amount of sorbent, and elution conditions, were investigated and properly established. The advantages of the present extraction method are the simplicity of implementation, rapidity, and low consumption of sorbent per extraction. Moreover, the pesticides on the adsorbent are stable, under certain storage conditions, rendering the cotton‐supported graphene suitable for environmental field studies. The applicability of the cotton–graphene‐based procedure for routine analysis was demonstrated by the determination of pesticides in a lake water sample. The recoveries ranged from 83 to 107%, the limits of quantitation were in the range of 0.02–0.09 μg/L, and the calculated relative standard deviations varied from 3 to 8% (data obtained with the same batch of sorbent). Because of the acceptable analytical characteristics, the developed method shows great prospects in determining certain classes of pesticides in water.     

Determination of natural olive fruit fly pheromone in insect samples by enzyme linked immunoassays

The olive fruit fly pheromone avidin-biotin ELISA immunoassay, based on the use of polyclonal G antibodies derived from rabbits (reported previously) and a newer assay, based on the use of polyclonal Y antibodies isolated from the eggs of laying hens (reported in this paper), were applied successfully for the analysis of natural pheromone in virgin adult female olive fruit flies. According to the results obtained, the pheromone content in the glands of adult female olive fruit flies increases from the third to the ninth day of their age. During the calling period, the female olive fruit flies seem to emit approximately 1.1microg pheromone/insect/day at least. The immunoassay, based on the Y antibodies, is slightly more sensitive (detection limit 40ng/mL) than the assay based on polyclonal anti-pheromone rabbit antiserum (detection limit 80ng/mL). As revealed by thorough cross-reactivity studies, including 14 structurally similar to the olive fruit fly pheromone molecules, the newer immunoassay is less selective than the previous one and seems to cross react with few molecules bearing the spiroketal moiety.