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.

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.

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.

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.

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.

CuCo2O4/N-Doped CNTs loaded with molecularly imprinted polymer for electrochemical sensor: Preparation, characterization and detection of metronidazole.

CuCo2O4 nanoparticles modified with nitrogen doped carbon nanotubes (CuCo2O4/N-CNTs) have high specific surface area and good electrical conductivity. Herein, a novel electrochemical sensor based on CuCo2O4/N-CNTs loaded molecularly imprinted polymer (MIP) modified glassy carbon electrode (GCE) is proposed for rapid and ultrasensitive detection of metronidazole (MNZ). The composite of CuCo2O4/N-CNTs with MIP significantly enhances the electrical signal. The electrochemical polymerization was performed with MNZ as template and aniline as functional monomer by cyclic voltammetry (CV), and differential pulse voltammetry (DPV) was used to detect MNZ. Factors that affect sensor response were optimized. Under the optimal experimental conditions, the DPV current response shows two linearity ranges for MNZ in the range of 0.005-0.1 µM and 0.1-100 µM with very low limit of detection (LOD) of 0.48 nM (S/N = 3). This electrochemical sensing system has high sensitivity, selectivity, excellent reproducibility, repeatability and stability. The recovery (95.9%-100.9%) and reasonable relative standard deviation (RSD) (3.2%-4.8%) for determination of real samples indicate the practicality of the sensing system. This sensing system has high potential for rapid determination of MNZ in samples such as metronidazole tablets, human serum and urine.

UPLC/MS/MS assay for the simultaneous determination of seven antibiotics in human serum-Application to pediatric studies.

A rapid and highly sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) assay was developed for quantification of 7 antibiotics in low sample volumes (50 µL): amoxicillin, azithromycin, cefotaxime, ciprofloxacin, meropenem, metronidazole and piperacillin, for both routine monitoring and pharmacokinetic studies. After protein precipitation by acetonitrile, the antibiotics were separated on an Acquity UPLC HSS T3 column (run time, 4 min). The mobile phase consisted of a mixture of (A) ammonium acetate (pH 2.4; 5 mM) and (B) acetonitrile acidified with 0.1% formic acid, delivered at 500 µl/min in a gradient elution mode. Total time run was 2.75 min. Ions were detected in the turbo-ion-spray-positive and multiple-reaction-monitoring modes. The assay was accurate and reproductible for the quantification of the seven antibiotics in serum samples over large concentration ranges.

Determination of total or free cefazolin and metronidazole in human plasma or interstitial fluid by HPLC-UV for pharmacokinetic studies in man.

Cefazolin (CFZ) plus metronidazole (MTZ) is commonly used for perioperative antibiotic prophylaxis. An HPLC-UV method is described for the simultaneous determination of total or free cefazolin and metronidazole in human plasma or in microdialysate of subcutaneous tissue. Separation was performed isocratically using a reversed phase column and phosphate buffer/acetonitrile as mobile phase. The validation characteristics were similar for both drugs. Linearity has been shown down to 0.1 mg/L (R > 0.9990). Intra- and inter-assay precision (CV) and in-accuracy were < 5%. The method was applied to the determination of cefazolin and metronidazole in plasma and microdialysate of surgical patients following 30-min intravenous infusion of cefazolin/metronidazole 2.0/0.5 g.

Biocompatible chitosan-pectin polyelectrolyte complex for simultaneous electrochemical determination of metronidazole and metribuzin.

Development of novel biocompatible sensor material suitable for modest, cost-effective, and rapid practical application is a demanding research interest in the field of electroanalytical chemistry. In this context, for the first time, we utilized biocompatible chitosan-pectin biopolyelectrolyte (CS-PC BPE) complex for the simultaneous electroreduction of an important antibiotic drug (metronidazole-MNZ) and herbicide (metribuzin-MTZ). This sensor reveals an attractive welfares such as simplicity, biocompatibility, and low production cost. Under optimized experimental conditions, the electroanalytical investigation confirmed that CS-PC BPE modified glassy carbon electrode (CS-PC BPE/GCE) was found to sense MNZ and MTZ in the nanomolar range. Moreover, as-prepared CS-PC BPE/GCE exhibited prominent selectivity, stability, and reproducibility. Additionally, the possible MNZ and MTZ sensing mechanism of CS-PC BPE/GCE have been discussed in detail. Lastly, real sample analysis was also carried out and revealed from several investigations that the CS-PC BPE/GCE is a good electrochemical sensor system for the detection of targeted analytes.

Metronidazole concentration in the bloodstream following its topical application, at different concentration levels, on experimental skin wounds during healing by secondary intention1.

PURPOSE: To characterize qualitatively and quantitatively the absorption of metronidazole solution, in greater concentrations and for longer periods, when applied topically to an experimental open skin wound model. METHODS: An open skin wound, 2 cm in diameter and total skin thickness was prepared, under anesthetic, in the dorsal region of 108 Wistar rats weighing between 300 and 350 grams. The animals were allocated to groups of 18 animals in accordance with the concentration of metronidazole in the solution to be applied daily to the wound. In the control group (CG), 0.9% sodium chloride solution was used for application, and in the experimental groups (GI, GII, GIII, GIV and GV) metronidazole solution at 4%, 6%, 8%, 10% and 12%, respectively, was applied. After 3, 7 and 14 days of treatment. Blood samples collected through cardiac puncture were examined for the existence or non-existence of metronidazole, using high performance liquid chromatography (HPLC). Detected metronidazole values were compared statistically within each group (temporal analysis 3 days X 7 days X 14 days) and between the groups that used topical metronidazole (4% X 6% X 8% X 10% and 12%) using the Kruskal-Wallis test, considering a statistical significance of 95% (p<0.05). RESULTS: Metronidazole was detected in all the samples at all times in all the groups in which topical metronidazole was applied to the wounds. Characteristically, there was no significant difference between the doses obtained within each group over time (3 days X 7 days X 14 days) GI=0.461; GII=0.154; GIII=0.888; GIV= 0.264 and GV=0.152. In the evaluation between groups, a similar degree of absorption was found after 3 days (p=0.829) and 14 days (p=0.751). CONCLUSION: The serum concentration of metronidazole that was achieved was not influenced by the concentration of the solution applied to the skin wound, with similar extend, or by the duration of the application.

Pharmacokinetic and Pharmacodynamic Properties of Metronidazole in Pediatric Patients With Acute Appendicitis: A Prospective Study.

BACKGROUND: Metronidazole is traditionally dosed every 6-8 hours even though in adults it has a long half-life, concentration-dependent killing, and 3-hour postantibiotic effect. Based on this logic, some pediatric hospitals adopted once-daily dosing for appendicitis, despite limited pharmacokinetics-pharmacodynamics (PK/PD) in children. We studied pediatric patients with appendicitis given metronidazole once daily to determine whether this dosing would meet target area under the curve (AUC)/minimum inhibitory concentration (MIC) ratio of ≥70 for Bacteroides fragilis. METHODS: One hundred pediatric patients aged 4-17 years had an average of 3 blood draws per patient during the first 24 hours after a 30 mg/kg per dose of intravenous metronidazole. Concentrations of drug were determined using validated liquid chromatography and tandem mass spectrometry. A NONMEM model was constructed for determining PK, followed by Monte Carlo simulations to generate a population of plasma concentration-time AUC of metronidazole and hydroxy-metronidazole. RESULTS: Simulated AUC values met target attainment (AUC/MIC ratio of ≥70 to B fragilis MICs) for 96%-100% of all patients for an MIC of 2 mcg/mL. For MICs of 4 and 8 mcg/mL, target attainment ranged from 61% to 97% and 9% to 71%, respectively. Areas under the curve were similar to that of adults receiving 1000 mg and 1500 mg q24, or 500 mg q8 hours. CONCLUSIONS: Metronidazole, 30 mg/kg per dose, once daily achieved AUC target attainment for B fragilis with an MIC of 2 mcg/mL or less in pediatric appendicitis patients. Based on this and studies in adults, there does not seem to be any PK/PD advantage of more frequent dosing in this population.

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 .

In-situ insertion of multi-walled carbon nanotubes in the Fe3O4/N/C composite derived from iron-based metal-organic frameworks as a catalyst for effective sensing acetaminophen and metronidazole.

In this paper, a novel Fe3O4/N/C@MWCNTs composite derived from iron-based metal-organic frameworks (H2N-Fe-MIL-88B) with multi-walled carbon nanotubes (MWCNTs) was prepared successfully through a simple calcination process. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy and electrochemical measurements were employed to comprehensive characterize the composites. Compare with the physical mixture, in-situ insertion of MWCNTs in the Fe3O4/N/C formed Fe3O4/N/C@MWCNTs composite has the higher conductivity, larger BET surface area and more satisfying electrocatalytic properties. Meanwhile, this composite with the reasonable combinations exhibits remarkable electrocatalytic activities for acetaminophen (AP) and metronidazole (MNZ) due to the synergistic interaction between the components. Thus, the Fe3O4/N/C@MWCNTs-2-600-based electrochemical sensor was established to effectively detect these two medicine molecules, respectively. In the optimized test conditions, the proposed sensor exhibits a wide linear response (0.5-5.0 µM and 5.0-1355.0 µM) for AP and the limit of detection (LOD) was achieved to be 0.14 µM (S/N = 3). Meanwhile, this sensor also shows two linear relationships with the concentration of MNZ in the range of 1.0 µM to 10.0 µM and 10.0 µM to 725.0 µM with the LOD of 0.19 µM (S/N = 3). Moreover, the satisfactory results were also acquired when the proposed sensor was used for the determination of AP and MNZ in the human serum and urine, demonstrating great promising of this electrochemical sensor for clinical applications.

Metronidazole concentration in the bloodstream following its topical application, at different concentration levels, on experimental skin wounds during healing by secondary intention

Abstract Purpose: To characterize qualitatively and quantitatively the absorption of metronidazole solution, in greater concentrations and for longer periods, when applied topically to an experimental open skin wound model. Methods: An open skin wound, 2 cm in diameter and total skin thickness was prepared, under anesthetic, in the dorsal region of 108 Wistar rats weighing between 300 and 350 grams. The animals were allocated to groups of 18 animals in accordance with the concentration of metronidazole in the solution to be applied daily to the wound. In the control group (CG), 0.9% sodium chloride solution was used for application, and in the experimental groups (GI, GII, GIII, GIV and GV) metronidazole solution at 4%, 6%, 8%, 10% and 12%, respectively, was applied. After 3, 7 and 14 days of treatment. Blood samples collected through cardiac puncture were examined for the existence or non-existence of metronidazole, using high performance liquid chromatography (HPLC). Detected metronidazole values were compared statistically within each group (temporal analysis 3 days X 7 days X 14 days) and between the groups that used topical metronidazole (4% X 6% X 8% X 10% and 12%) using the Kruskal-Wallis test, considering a statistical significance of 95% (p<0.05). Results: Metronidazole was detected in all the samples at all times in all the groups in which topical metronidazole was applied to the wounds. Characteristically, there was no significant difference between the doses obtained within each group over time (3 days X 7 days X 14 days) GI=0.461; GII=0.154; GIII=0.888; GIV= 0.264 and GV=0.152. In the evaluation between groups, a similar degree of absorption was found after 3 days (p=0.829) and 14 days (p=0.751). Conclusion: The serum concentration of metronidazole that was achieved was not influenced by the concentration of the solution applied to the skin wound, with similar extend, or by the duration of the application.

Development of a UPLC-MS/MS method for quantitation of metronidazole and 2-hydroxy metronidazole in human plasma and its application to a pharmacokinetic study.

An ultra-performance liquid-chromatography mass-spectrometry (UPLC-MS/MS) method for simultaneous quantitation of metronidazole and 2-hydroxymetronidazole in human plasma was developed and validated. Metronidazole and 2-hydroxymetronidazole were extracted from a small volume of human plasma (10 µL) by hydrophilic lipophilic balanced solid phase extraction on 96-well µ-elution plates. Chromatographic separation of analytes was achieved on an Acquity UPLC BEH C18 column (1.7 µm, 2.1 × 100 mm) using gradient elution with a blend of 0.1% formic acid in water and 0.1% formic acid in methanol at a flow rate of 0.25 mL/min. Mass spectrometric detection was achieved using multiple reaction monitoring (MRM) in positive-ion electrospray-ionization (ESI) mode. Ion transitions were optimized at m/z 171.85->127.9 for metronidazole and m/z 187.9->125.9 for 2-hydroxymetronidazole. The assay was linear for both analytes over the concentration range of 0.1-300 µM; intra- and inter-assay precisions and accuracies were <13%. Recoveries for metronidazole and 2-hydroxymetronidazole ranged from 88 to 99% and 78 to 86%, respectively. Matrix effects for metronidazole and 2-hydroxymetronidazole in plasma ranged from 102 to 105% and 99 to 106%, respectively. The method was successfully applied to determine metronidazole and 2-hydroxymetronidazole plasma concentrations in a pharmacokinetic study conducted in adults administered an oral dose of 500 mg metronidazole. Pharmacokinetic parameters were comparable to previously reported values. By design, this method is amenable to high sample throughput and has the potential to be automated.

Development of a LC-MS method for simultaneous determination of amoxicillin and metronidazole in human serum using hydrophilic interaction chromatography (HILIC).

A method was developed for the determination of amoxicillin and metronidazole in human serum. The procedure used was hydrophilic interaction chromatography (HILIC) followed by mass spectrometric (MS) detection. Chromatographic separation was achieved on a ZIC-HILIC column and the mobile phase consisted of a mixture of 0.1% (v/v) formic acid in water and 0.1% (v/v) formic acid in acetonitrile. The method was validated with regard to selectivity, accuracy, precision, calibration, lower limit of quantification (LOQ), extraction recovery and matrix effect. The LOQs were 0.0138 and 0.008 µg/ml for amoxicillin and metronidazole respectively, while for quantification purposes linearity was achieved in the range of 0.1 µg/ml to 6.4 µg/ml for both drugs with correlation coefficients >0.9990. The intraday precision (expressed as %RSD) and the accuracy (expressed as the % deviation from the nominal value) was <15% for both antibiotics at all QC levels. Extraction recoveries for both drugs and internal standards were >80%, while a considerable matrix effect (<60%) was observed for amoxicillin. Finally, the method was applied to the determination of amoxicillin and metronidazole concentrations in serum for 20 patients.

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.

Green synthesis of graphitic carbon nitride nanosheet (g-C3N4) and using it as a label-free fluorosensor for detection of metronidazole via quenching of the fluorescence.

In this research, g-C3N4nanosheets were facilely fabricated by thermal polymerization and then exfoliated into ultrathin nanosheets through ultrasonication in water media. Low-cost C-N nanosheets prepared by melamine possessed a highly π-conjugated structure and fluorescence property. In the present study, the g-C3N4nanosheet was used as a switch-off fluorescence sensor for rapid and sensitive sensing of metronidazole in biological fluids. These nanosheets were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy. The fluorescence of the solution of the g-C3N4nanosheets was quenched effectively by metronidazole through two mechanisms: fluorescence resonance energy transfer and the formation of a donor-acceptor charge-transfer complex between π-electron rich donors. Under optimal conditions, the detection linear range for metronidazole was found to be from 0.01 to 0.10µgml-1, with a limit of detection (LOD) of 0.008µgml-1 which can cover standard range of metronidazole in real samples. Moreover, the proposed method has offered a green, rapid, and sensitive probe for quantitative determination of metronidazole in drug and biological fluids.