Asparagus officinalis Herb-Derived Carbon Quantum Dots: Luminescent Probe for Medical Diagnostics.

The utilization of natural materials for the synthesis of highly fluorescent carbon quantum dots (CQDs) presents a sustainable approach to overcome the challenges associated with traditional chemical precursors. Here, we report the synthesis of novel S,N-self-doped CQDs (S,N@CQDs) derived from asparagus officinalis herb. These S,N@CQDs exhibit 16.7 % fluorescence quantum yield, demonstrating their potential in medical diagnostics. We demonstrate the efficacy of S,N@CQDs as luminescent probes for the detection of anti-pathogenic medications metronidazole (MTZ) and nitazoxanide (NTZ) over concentration ranges of 0.0-180.0 µM (with a limit of detection (LOD) of 0.064 µM) and 0.25-40.0 µM (LOD of 0.05 µM), respectively. The probes were successfully applied to determine MTZ and NTZ in medicinal samples, real samples, and spiked human plasma, with excellent recovery rates ranging from 99.82 % to 103.03 %. Additionally, S,N@CQDs demonstrate exceptional efficacy as diagnostic luminescent probes for hemoglobin (Hb) detection over a concentration range of 0-900 nM, with a minimal detectability of 9.24 nM, comparable to commercially available medical laboratory diagnostic tests. The eco-friendly synthesis and precise detection limits of S,N@CQDs meet necessary analytical requirements and hold promise for advancing diagnostic capabilities in clinical settings. This research signifies a significant step towards sustainable and efficient fluorescence-based medical diagnostics.

A fast-screening dispersive liquid-liquid microextraction-gas chromatography-mass spectrometry method applied to the determination of efavirenz in human plasma samples.

We demonstrate the suitability of a fast, green, easy-to-perform, and modified sample extraction procedure, i.e., dispersive liquid-liquid microextraction (DLLME) for the determination of efavirenz (EFV) in human plasma. Data acquisition was done by gas chromatography-mass spectrometry (GC-MS) in the selected ion monitoring (SIM) mode. The simplicity of the method lies in, among others, the avoidance of the use of large organic solvent volumes as mobile phases and non-volatile buffers that tend to block the plumbing in high-performance liquid chromatography (HPLC). Chromatographic and mass spectral parameters were optimized using bovine whole blood for matrix matching due to insufficient human plasma. Method validation was accomplished using the United States Food and Drug Administration (USFDA) 2018 guidelines. The calibration curve was linear with a dynamic range of 0.10-2.0 µg/mL and an R2 value of 0.9998. The within-run accuracy and precision were both less than 20% at the lower limit of quantification (LLOQ) spike level. The LLOQ was 0.027 µg/mL which compared well with some values but was also orders of magnitude better than others reported in the literature. The percent recovery was 91.5% at the LLOQ spike level. The DLLME technique was applied in human plasma samples from patients who were on treatment with EFV. The human plasma samples gave concentrations of EFV ranging between 0.14-1.00 µg/mL with three samples out of seven showing concentrations that fell within or close to the recommended therapeutic range.

Computational modeling, fabrication, and characterization of the deep eutectic solvent-based green molecular cage for selective metronidazole extraction from plasma followed by UHPLC with diode array detector determination.

Four ternary deep eutectic solvents were computationally designed and synthesized, being used as candidate functional monomers in metronidazole molecular imprinting polymer synthesis, allowing selective extraction and determination by ultra high performance liquid chromatography with diode array detection. In terms of metronidazole selective extraction, the best results were obtained by (deep eutectic solvent)2 :(ethylene glycol dimethacrylate)11 , in which deep eutectic solvent is the functional monomer constructed by combining three components in 6:6:2 ratios of choline chloride:ethylene glycol:methacrylic acid. The effects of different parameters on molecular imprinted solid-phase extraction of metronidazole were thoroughly explored through screening design and response surface methodology. The adsorption mechanism findings show that the adsorption data are primarily fitted on the Freundlich model based on higher correlation coefficient. Kinetic experiments have shown that the mechanism of adsorption fits the pseudo-second-order model. The best extraction recovery (96.5%) was obtained in 25-min elution time, desorption temperature of 40°C, and 1.0 mL ACN as eluent. Metronidazole was measured by a validated ultra high performance liquid chromatography with diode array detection method. The calibration of the method was linear in the range of 0.1-10 µg/mL with limits of detection and quantification of 0.03 and 0.1 µg/mL, respectively. The method was successfully applied for the determination of metronidazole in human plasma.

HPLC Determination of Imidazoles with Variant Anti-Infective Activity in Their Dosage Forms and Human Plasma.

A suitable HPLC method has been selected and validated for rapid simultaneous separation and determination of four imidazole anti-infective drugs, secnidazole, omeprazole, albendazole, and fenbendazole, in their final dosage forms, in addition to human plasma within 5 min. The method suitability was derived from the superiority of using the environmentally benign solvent, methanol over acetonitrile as a mobile phase component in respect of safety issues and migration times. Separation of the four anti-infective drugs was performed on a Thermo Scientific® BDS Hypersil C8 column (5 µm, 2.50 × 4.60 mm) using a mobile phase consist of MeOH: 0.025 M KH2PO4 (70:30, v/v) adjusted to pH 3.20 with ortho-phosphoric acid at room temperature. The flow rate was 1.00 mL/min and maximum absorption was measured with UV detector set at 300 nm. Limits of detection were reported to be 0.41, 0.13, 0.18, and 0.15 µg/mL for secnidazole, omeprazole, albendazole, and fenbendazole, respectively, showing a high degree of the method sensitivity. The method of analysis was validated according to Food and Drug Administration (FDA)guidelines for the determination of the drugs, either in their dosage forms with highly precise recoveries, or clinically in human plasma, especially regarding pharmacokinetic and bioequivalence studies.

Colo-Pro: a pilot randomised controlled trial to compare standard bolus-dosed cefuroxime prophylaxis to bolus-continuous infusion-dosed cefuroxime prophylaxis for the prevention of infections after colorectal surgery.

Standard bolus-dosed antibiotic prophylaxis may not inhibit growth of antibiotic resistant colonic bacteria, a cause of SSIs after colorectal surgery. An alternative strategy is continuous administration of antibiotic throughout surgery, maintaining concentrations of antibiotics that inhibit growth of resistant bacteria. This study is a pilot comparing bolus-continuous infusion with bolus-dosed cefuroxime prophylaxis in colorectal surgery. This is a pilot randomised controlled trial in which participants received cefuroxime bolus-infusion (intervention arm) targeting free serum cefuroxime concentrations of 64 mg/L, or 1.5 g cefuroxime as a bolus dose four-hourly (standard arm). Patients in both arms received metronidazole (500 mg intravenously). Eligible participants were adults undergoing colorectal surgery expected to last for over 2 h. Results were analysed on an intention-to-treat basis. The study was successfully piloted, with 46% (90/196) of eligible patients recruited and 89% (80/90) of participants completing all components of the protocol. A trialled bolus-continuous dosing regimen was successful in maintaining free serum cefuroxime concentrations of 64 mg/L. No serious adverse reactions were identified. Rates of SSIs (superficial and deep SSIs) were lower in the intervention arm than the standard treatment arm (24% (10/42) vs. 30% (13/43)), as were infection within 30 days of operation (41% (17/43) vs 51% (22/43)) and urinary tract infections (2% (1/42) vs. 9% (4/43)). These infection rates can be used to power future clinical trials. This study demonstrates the feasibility of cefuroxime bolus-continuous infusion of antibiotic prophylaxis trials, and provides safety data for infusions targeting free serum cefuroxime concentrations of 64 mg/L. Trial registration: NCT02445859 .

Quantification of metronidazole in human plasma using a highly sensitive and rugged LC-MS/MS method for a bioequivalence study.

A highly sensitive, selective and rugged method has been described for the quantification of metronidazole (MTZ) in human plasma by liquid chromatography-tandem mass spectrometry using metronidazole-d4 as the internal standard (IS). The analyte and the IS were extracted from 100 µL plasma by liquid-liquid extraction. The clear samples obtained were chromatographed on an ACE C18 (100 × 4.6 mm, 5 µm) column using acetonitrile and 10.0 mm ammonium formate in water, pH 4.00 (80:20, v/v) as the mobile phase. A triple quadrupole mass spectrometer system equipped with turbo ion spray source and operated in multiple reaction monitoring mode was used for the detection and quantification of MTZ. The calibration range was established from 0.01 to 10.0 µg/mL. The results of validation testing for precision and accuracy, selectivity, matrix effects, recovery and stability complied with current bioanalytical guidelines. A run time of 3.0 min permitted analysis of more than 300 samples in a day. The method was applied to a bioequivalence study with 250 mg MTZ tablet formulation in 24 healthy Indian males.

Electrochemical sensor based on molecularly imprinted polymer for sensitive and selective determination of metronidazole via two different approaches.

A molecularly imprinted polymer decorated glassy carbon electrode (MIP/GCE) is facilely developed into an electrochemical sensing platform for detection of metronidazole (MNZ). MIP preparation was carried out via in situ electropolymerization and o-phenylenediamine was selected as the optimal functional monomer. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were employed to characterize and assess the performance of the so-obtained sensor. In particular, two assay methods, which are based on different principles, were involved in the detection procedure. One is based on MIP/catalysis (Method І) and the other is MIP/gate effect (Method II). Comparison of these two methods was made in the aspects including detection range, sensitivity, accuracy, selectivity, repeatability, and long-term stability. It is found that Method І affords a lower detection limit of 3.33 × 10(-10) M (S/N = 3) while the detection limit of Method II is 6.67 × 10(-10) M (S/N = 3). The linear range of Method І and II is 1.0 × 10(-9) to 1.0 × 10(-8) M and 2.0 × 10(-9) to 1.0 × 10(-7) M, respectively. The MIP/GCE exhibits good recognition ability towards the template molecule-MNZ in the presence of the analogues of MNZ and other interferents, which can be ascribed to the successful imprinting effect during MIP membrane preparation. Graphical Abstract Procedure for fabricating MIP/GCE and its application in detecting metronidazole in serum.

Metronidazole pharmacokinetics during rapid growth in turkeys - relation to changes in haemodynamics and drug metabolism.

Whereas interspecies variation in pharmacokinetics is a commonly investigated issue, variations in drug kinetics within a species are less documented. The aim of the study was to assess the influence of age-related changes in haemodynamics on the pharmacokinetics of metronidazole (MTZ) and its hydroxy metabolite (MTZ-OH) in turkeys. MTZ was administered intravenously and orally at a dose of 25 mg/kg. Plasma drug and metabolite concentrations were assessed by high-performance liquid chromatography, and pharmacokinetic parameters were calculated by noncompartmental analysis. Haemodynamic parameters (heart rate, stroke volume, cardiac output) were assessed by echocardiography and extraction ratio for MTZ was calculated based on total body clearance (ClB ). Between the 5th and 15th week of age, ClB of MTZ decreased from 3.6 to 1.2 mL/min/kg causing a twofold increase in the mean residence time (MRT) and elimination half-life (T1/2el ). The MTZ-OH production decreased threefold and its MRT and T1/2el increased. Although heart rate significantly decreased with age, cardiac output increased. Extraction ratio was low in all age groups. It is concluded that significant age-dependent decrease in ClB of MTZ in turkeys resulted from decreased perfusion of the clearing organs and their reduced metabolic capacity. This phenomenon is probably species specific and may apply to other therapeutic agents.

Analysis of metronidazole in equine plasma using liquid chromatography/tandem mass spectrometry and high-resolution accurate mass spectrometry.

RATIONALE: Treatment of racehorses with bicarbonate solutions to manage acidosis and muscle cramps prior to competition is banned in Pennsylvania (PA). Use of excess bicarbonate in horses causes diarrhea, requiring treatment with an antibiotic such as metronidazole (MTNZ). At present no method exists for detecting MTNZ in equine plasma. Thus, a liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the detection, quantification and confirmation of MTNZ was developed. METHODS: The analyte was recovered from plasma by liquid-liquid extraction using methyl tert-butyl ether and separated on an ACE® C18 column with its guard column. The mobile phase comprised a mixture of 5 mM ammonium formate (pH 3.5) and acetonitrile (60:40; v/v). Mass analysis was performed on an LTQ XL linear ion trap mass spectrometer in positive electrospray ionization mode while accurate mass determination was also performed in positive electrospray ionization mode using high-resolution accurate mass spectrometry (HRAMS). RESULTS: The limit of detection (LOD), limit of confirmation (LOC) and lower limit of quantification (LLOD) were 1, 2 and 50 ng/mL, respectively. The analyte in plasma was stable at -20 and -70°C for 28 days, as well as for 24 h at 20°C in the autosampler. The percentage coefficients of variation (% CV) for the intra-day and inter-day precision for the LLOQ were 5.1:3.68 and 13.21:9.95, respectively, while the intra-day accuracy was from 98.71 to 101.57% and that of the inter-day was from 88.64 to 96.6%. The matrix effect was between 9 and 24%. The precursor → product ion transition m/z 172 → 128, a retention time of 2.92 min and the accurate mass of the [M+H](+) ion of the analyte (m/z 172.0173) were used as criteria for confirmation of the presence of MTNZ in equine plasma. CONCLUSIONS: The method is highly sensitive and selective for the detection, identification and confirmation of MTNZ in equine plasma. Thus, illegal use of MTNZ in racehorses can be routinely monitored within the US State of Pennsylvania. The method is fast, sensitive, reproducible, and reliable.

A rapid and sensitive determination of hypoxic radiosensitizer agent nimorazole in rat plasma by LC-MS/MS and its application to a pharmacokinetic study.

A highly sensitive, accurate and robust LC-MS/MS method was developed and validated for determination of nimorazole (NMZ) in rat plasma using metronidazole (MNZ) as internal standard (IS). The analyte and IS were extracted from plasma by precipitating protein with acetonitrile and were chromatographed using an Agilent Poroshell 120, EC-C18 column. The mobile phase was composed of a mixture of acetonitrile and 0.1 % formic acid (85:15 v/v). The total run time was 1.5 min and injection volume was 5 µL. Multiple reaction monitoring mode using the transitions of m/z 227.1 → m/z 114.0 for MNZ and m/z 172.10 → m/z 128.1 for IS were monitored on a triple quadrupole mass spectrometer, operating in positive ion mode. The calibration curve was linear in the range of 0.25-200 ng/mL (r(2) > 0.9996) and the lower limit of quantification was 0.25 ng/mL in the rat plasma samples. Recoveries of NMZ ranged between 88.05 and 95.25%. The precision (intra-day and inter-day) and accuracy of the quality control samples were 1.25-8.20% and -2.50-3.10, respectively. The analyte and IS were found to be stable during all sample storage and analysis procedures. The LC-MS/MS method described here was validated and successfully applied to pharmacokinetic study in rats.

Pharmacokinetics of metronidazole in foals: influence of age within the neonatal period.

Neonatal foals have unique pharmacokinetics, which may lead to accumulation of certain drugs when adult horse dosage regimens are used. Given its lipophilic nature and requirement for hepatic metabolism, metronidazole may be one of these drugs. The purpose of this study was to determine the pharmacokinetic profiles of metronidazole in twelve healthy foals at 1-2.5 days of age when administered as a single intravenous (IV) and intragastric (IG) dose of 15 mg/kg. Foals in the intravenous group were studied a second time at 10-12 days of age to evaluate the influence of age on pharmacokinetics within the neonatal period. Blood samples were collected at serial time points after metronidazole administration. Metronidazole concentration in plasma was measured using LC-MS. Pharmacokinetic parameters were determined using noncompartmental analysis and compared between age groups. At 1-2.5 days of age, the mean peak plasma concentration after IV infusion was 18.79 ± 1.46 µg/mL, elimination half-life was 11.8 ± 1.77 h, clearance was 0.84 ± 0.13 mL/min/kg and the volume of distribution (steady-state) was 0.87 ± 0.07 L/kg. At 10-12 days of age, the mean peak plasma concentration after IV infusion was 18.17 ± 1.42 µg/mL, elimination half-life was 9.07 ± 2.84 h, clearance was 1.14 ± 0.21 mL/min/kg and the volume of distribution (steady-state) was 0.88 ± 0.06 L/kg. Oral approximated bioavailability was 100%. Cmax and Tmax after oral dosing were 14.85 ± 0.54 µg/mL and 1.75 (1-4) h, respectively. The elimination half-life was longer and clearance was reduced in neonatal foals at 1-2.5 days as compared to 10-12 days of age (P = 0.006, P = 0.001, respectively). This study warrants consideration for altered dosing recommendations in foals, especially a longer interval (12 h).

Novel fluorescent membrane for metronidazole sensing prepared by covalent immobilization of a pyrenebutyric acid derivative.

In the present paper, we report the fabrication of a new sensing membrane for fluorescence detection of metronidazole (MNZ). Briefly, a pyrenebutyric acid derivative, 2-(methacryloyloxy) ethyl-4-(1-pyrenyl) butanoate (MPB) with a double bond, was synthesized and copolymerized with 2-hydroxyethylmethacrylate (HEMA) on the activated glass surface by thermal initiation in the presence of cross-linker. The sensor responds linearly to metronidazole in the concentration range of 1.23~35.48 mg.L(-1) in aqueous solution with a detection limit of 0.36 mg.L(-1). The lifetime is enhanced by covalently immobilizing the pyrenebutyric acid derivative on glass slide, which hinders leaching of the dye from the membrane. The sensor could be regenerated after use by washing in methanol (RSD = 2.42 %), and it shows sufficient stability, and selectivity. Interference of other pharmaceuticals on membrane performance is discussed. The developed membrane has been successfully applied for the direct determination of metronidazole in human serum sample without pretreatment.

In vivo evaluation of a radiogallium-labeled bifunctional radiopharmaceutical, Ga-DOTA-MN2, for hypoxic tumor imaging.

On the basis of the findings obtained by X-ray crystallography of Ga-DOTA chelates and the drug design concept of bifunctional radiopharmaceuticals, we previously designed and synthesized a radiogallium-labeled DOTA chelate containing two metronidazole moieties, (67)Ga-DOTA-MN2, for hypoxic tumor imaging. As expected, (67)Ga-DOTA-MN2 exhibited high in vivo stability, although two carboxyl groups in the DOTA skeleton were conjugated with metronidazole moieties. In this study, we evaluated (67/68)Ga-DOTA-MN2 as a nuclear imaging agent for hypoxic tumors. (67)Ga-labeling of DOTA-MN2 with (67)GaCl(3) was achieved with high radiochemical yield (>85%) by 1-min of microwave irradiation (50 W). The pharmacokinetics of (67)Ga-DOTA-MN2 were examined in FM3A tumor-bearing mice, and compared with those of (67)Ga-DOTA-MN1 containing one metronidazole unit and (67)Ga-DOTA. Upon administration, (67)Ga-DOTA-MN2 exhibited higher accumulation in the implanted tumors than (67)Ga-DOTA. Tumor-to-blood ratios of (67)Ga-DOTA-MN2 were about two-fold higher than those of (67)Ga-DOTA-MN1. Autoradiographic analysis showed the heterogeneous localization of (67)Ga-DOTA-MN2 in the tumors, which corresponds to hypoxic regions suggested by well-established hypoxia marker drug, pimonidazole. Furthermore, in positron emission tomography (PET) study, the tumors of mice administered (68)Ga-labeled DOTA-MN2 were clearly imaged by small-animal PET at 1 h after administration. This study demonstrates the potential usefulness of (67/68)Ga-DOTA-MN2 as a nuclear imaging agent for hypoxic tumors and suggests that two functional moieties, such as metronidazole, can be conjugated to radiogallium-DOTA chelate without reducing the complex stability. The present findings provide useful information about the chemical design of radiogallium-labeled radiopharmaceuticals for PET and single photon emission computed tomography (SPECT) studies.

Investigation of the safety of topical metronidazole from a pharmacokinetic perspective.

Metronidazole (MTZ) ointment has been used widely as a hospital preparation against cancerous malodor. Although cancerous tissue with ulcer-like symptoms is likely to have a higher capacity to absorb drugs than normal skin, the extent to which MTZ is absorbed when a topical preparation is applied to cancerous tissue remains unclear. Furthermore, few studies have investigated the drug interactions involving MTZ despite its long use in clinical practice. In the present study, plasma concentration of MTZ was measured in a breast cancer patient using MTZ ointment for cancerous malodor and basic research was also conducted with the objective of investigating the safety of topical MTZ from a pharmacokinetic perspective. 4.75 µg/mL (27.8 µM) of MTZ was detected in the patient's plasma, which was close to the plasma concentration after oral dosage of MTZ. In a metabolic inhibition study using human liver microsomes, cytochrome P450 (CYP) 2C9-mediated hydroxylation of S-warfarin was almost unaffected by MTZ at the corresponding concentrations. In addition, 3-d repeated oral administration of MTZ (200 mg/kg/d) to rats did not show any significant effects on the hepatic mRNA levels of various CYP isozymes and CYP2C protein levels. These results suggest that the reported interaction of oral MTZ and S-warfarin was not due to CYP2C9 inhibition and that drug interactions via inhibition of CYP2C9 is unlikely to occur when MTZ ointment is applied to ulcerous skin. This information should be valuable for assessing the safety of MTZ ointment used for mitigating cancerous malodor.

Development and validation of a dried blood spot-HPLC assay for the determination of metronidazole in neonatal whole blood samples.

A selective and sensitive high-performance liquid chromatography method with UV detection for the determination of metronidazole in dried blood spots (DBS) has been developed and validated. DBS samples [spiked or patient samples] were prepared by applying blood (30 microL) to Guthrie cards. Discs (6 mm diameter) were punched from the cards and extracted using water containing the internal standard, tinidazole. The extracted sample was chromatographed without further treatment using a reversed phase system involving a Symmetry(R) C18 (5 microm, 3.9 x 150 mm) preceded by a Symmetry(R) guard column of matching chemistry and a detection wavelength of 317 nm. The mobile phase comprised acetonitrile/0.01 M phosphate solution (KH(2)PO(4)), pH 4.7, 15:85, v/v, with a flow rate of 1 mL/min. The calibration was linear over the range 2.5-50 mg/mL. The limits of detection and quantification were 0.6 and 1.8 microg/mL, respectively. The method has been applied to the determination of 203 DBS samples from neonatal patients for a phamacokinetic/pharmacodynamic study.

Fabrication of carbon dots@restricted access molecularly imprinted polymers for selective detection of metronidazole in serum.

A custom-tailored design was proposed for the fabrication of carbon dots coupled with restricted access materials and molecularly imprinted polymers (CDs@RAM-MIPs) to detect metronidazole (MNZ). Biomass carbon dots (CDs) were derived from longan peels assisted with high pressure microwave, and had the merits of eco-friendly, excellent photostability and low toxicity. In this work, glycidyl methacrylate was used as a co-polymeric monomer to increase hydroxyl groups on the surface of synthetic materials, which eliminated the interference of biological macromolecules. The specific binding cavities of CDs@RAM-MIPs were formed after removing the template molecule (MNZ). The obtained CDs@RAM-MIPs can selectively capture MNZ through the specific interaction between recognition sites and MNZ, and obey photoinduced electron transfer fluorescence quenching mechanism. The highly sensitive and selective fluorescent sensor based CDs@RAM-MIPs had a wide linear range (50-1200 ng mL-1) and a low detection limit (17.4 ng mL-1) for MNZ. It has been utilized to detect MNZ in serum with recoveries of 93.5%-102.7%, and the relative standards (RSDs) were 1.9%-3.6%, respectively. This work provides a thoughtful strategy for preparation and application of CDs@RAM-MIPs, which presages its great potential for detecting trace compounds in real samples.

Cerium doped magnetite nanoparticles for highly sensitive detection of metronidazole via chemiluminescence assay.

Cerium doped magnetite nanoparticle (CDM) was synthesized via a co-precipitation method and used as the co-reactant of luminol-K3Fe(CN)6 chemiluminescent system. The physical-chemical features of CDM were studied by XPS, XRD, HRTEM, FESEM, VSM, BET, and FTIR analyses. This simple and highly sensitive nanoprobe enabled the determination of minor concentrations of metronidazole (MNZ). Owing to the quenching efficacy of MNZ in the studied chemiluminescence system, a linear range of 3.47 × 10-6-9.37 × 10-5 mol/L was obtained with a limit of detection of 3.91 × 10-7 mol/L. This biosensor was used for MNZ detection in human serum samples, which was highly efficient. The outcomes of this study give credit to the proposed biosensor to be applied for detection of MNZ in biological samples.

Quantification of metronidazole in human bile fluid and plasma by liquid chromatography-tandem mass spectrometry.

This study was conducted to develop a highly selective, sensitive, and validated method for quantifying metronidazole in human plasma and bile fluid. Metronidazole and metronidazole-d4 (internal standard) were extracted from 100 µL of plasma and bile fluid by liquid-liquid extraction. Liquid chromatography with a Hydrosphere C18 column (50 × 2.0 mm) was performed using 10 mM ammonium formate (pH 4.0) and acetonitrile (20:80, v/v) as the mobile phase. Triple quadrupole mass spectrometry was operated with an electrospray ionization interface in multiple reaction monitoring and positive ion modes. The calibration curves were linear for bile and plasma samples over the range of 50-20,000 ng/mL (r2 > 0.999). The intra- and inter-day coefficients of variation (CVs) for plasma ranged from 2.50% to 7.85% and 3.11% to 16.9%, respectively; for bile, the intra-and inter-run precision (CVs) ranged from 2.76% to 13.2% and 3.16% to 11.5%, respectively. The mean extraction recovery for metronidazole ranged from 76.5% to 82.1% in plasma and from 78.8% to 87.8% in bile, respectively. Our proposed analytical method was successfully applied to determine metronidazole concentrations in bile as well as in plasma at multiple time points in a patient with acute cholangitis.

The plasma pharmacokinetics of fosfomycin and metronidazole after intraperitoneal administration in patients undergoing appendectomy for uncomplicated appendicitis.

We aimed to investigate the pharmacokinetics of fosfomycin and metronidazole after intraperitoneal administration of the combination of fosfomycin and metronidazole in patients undergoing laparoscopic appendectomy for uncomplicated appendicitis. We included eight otherwise healthy men undergoing laparoscopic appendectomy. The trial treatment was administered at the end of the surgical procedure and left in the abdominal cavity. Trial drugs consisted of 4 g fosfomycin and 1 g metronidazole in a total volume of 500.2 mL. Blood samples were collected prior to and ½, 1, 2, 4, 8, 12 and 24 h after administration. High-performance liquid chromatography-mass spectrometry was used for the measurement of plasma concentrations, and pharmacokinetic calculations were undertaken. Antimicrobial susceptibility testing was undertaken on isolates from intraoperatively collected specimens. The median maximal concentration for fosfomycin in plasma was 104.4 mg/L, median time point for the maximal concentration was 1.5 h, median half-life 3.0 h, and median area under the curve 608 mg*h/L. The median maximal concentration for metronidazole in plasma was 13.6 mg/L, median time point for the maximal concentration was 2.0 h, median half-life 7.3 h, and median area under the curve was 164 mg*h/L. All aerobic bacteria were susceptible to fosfomycin, and all anaerobes were susceptible to metronidazole. Plasma concentrations of fosfomycin and metronidazole were in line with concentrations reported from pharmacokinetic studies after intravenous administration and were within therapeutic ranges.

Ion mobility spectrometry as a detector for molecular imprinted polymer separation and metronidazole determination in pharmaceutical and human serum samples.

Application of ion mobility spectrometry (IMS) as the detection technique for a separation method based on molecular imprinted polymer (MIP) was investigated and evaluated for the first time. On the basis of the results obtained in this work, the MIP-IMS system can be used as a powerful technique for separation, preconcentration, and detection of the metronidazole drug in pharmaceutical and human serum samples. The method is exhaustively validated in terms of sensitivity, selectivity, recovery, reproducibility, and column capacity. The linear dynamic range of 0.05-70.00 microg/mL was obtained for the determination of metronidazole with IMS. The recovery of analyzed drug was calculated to be above 89%, and the relative standard deviation (RSD) was lower than 6% for all experiments. Various real samples were analyzed with the coupled techniques, and the results obtained revealed the efficient cleanup of the samples using MIP separation before the analysis by IMS as a detection technique.