Elimination of matrix effects in urine for determination of ethyl glucuronide by liquid chromatography-tandem mass spectrometry.

RATIONALE: Alcohol use disorder affects 4% to 5% of the world's population. Analysis methods are available for various biological fluids to detect this disorder. Determination of ethyl glucuronide in urine by the liquid chromatography-tandem mass spectrometry (LC/MS/MS) method is frequently used in forensic toxicology. These analyses are known to cause matrix effects. METHODS: The presented study describes the elimination of matrix effects for ethyl glucuronide. This study used two different LC/MS/MS systems containing orthogonal and z-spray ion sources. Ethyl glucuronide was analyzed in negative polarity in electrospray ionization. A different dilution method was chosen for each study. The methods were developed and validated according to the European Medicines Agency bioanalytical method validation parameters. RESULTS: The lower limit of quantitation of the developed methods was 0.025 µg/mL for ethyl glucuronide. The calibration curve of ethyl glucuronide was between 0.025 and 100 µg/mL with a correlation coefficient of >0.99 for the two methods. CONCLUSIONS: It was determined that the analyses using the z-spray ion source were more affected by the matrix effect. The two validated methods involve rapid analysis time and simple sample preparation. Also, the methods were applied to real patients' urine.

Determination of cefuroxime in breast milk by LC-MS/MS using SALLME technique.

The World Health Organization recommends that infants be exclusively breastfed for the first 6 months. Antibiotics are among the most commonly prescribed drugs for pregnant and lactating women. The vast majority of drugs pass into breast milk, which may create a risk for the infant. In cases where drug exposure may pose a risk, breastfeeding should be discontinued. Therefore, the mother's drug use should be decided by considering the most accurate and recent data. Cefuroxime is a second-generation cephalosporin antibiotic with a broad spectrum of activity against Gram-negative and -positive microorganisms. In this study, we aimed to develop the LC-MS/MS method using salt-assisted liquid-liquid micro-extraction (SALLME) for the determination of cefuroxime in breast milk. The method was validated according to the European Medicines Agency (EMA) guidelines. Cefuroxime and the internal standard cefixime were extracted from plasma by a SALLME technique. The results obtained from the entire validation study are at an acceptable level according to the EMA criteria. The calibration curve of cefuroxime was between 25 and 1000 ng/ml, with correlation coefficients of >0.99. The lower limit of quantitation was 25 ng/ml for cefuroxime. Furthermore, the developed method was applied for the determination of cefuroxime in real patient breast milk.

Determination of levetiracetam in human plasma by online heart-cutting liquid chromatography: Application to therapeutic drug monitoring.

Levetiracetam is an antiepileptic drug for the treatment of psychiatric patients. In this study, a selective, straightforward, and rapid online heart-cutting liquid chromatography method was developed for the therapeutic drug monitoring of levetiracetam. This method allows for the determination of levetiracetam in human plasma without complex sample preparation. The mobile phases consisted of 30 mM aq. orthophosphoric acid solution/methanol (70:30) at a flow rate of 1 mL/min for the first system and 10 mM aq. orthophosphoric acid solution/methanol (55:45) at a flow rate of 1 mL/min for the second system. The first separation was carried out on a GL Sciences Intersil ODS-3 column (4.6 mm × 150 mm, 3 µm) and the second separation was carried out on a Restek Ultra PFPP column (4.6 mm × 150 mm, 5 µm). The detection was carried out at 205 nm for both systems. The method was validated for selectivity and linearity, which were in the 6-60 µg/mL range. Intra- and interassay accuracies were <112.6%, and the intra- and interassay precisions were <6.4% for all quality control samples. The lower limit of quantitation was 6 µg/mL. The developed method was successfully applied for therapeutic drug monitoring of plasma samples from patients.

Determination of acamprosate in human plasma by UPLC-MS/MS: Application to therapeutic drug monitoring.

Acamprosate is a medication used to treat alcohol dependence. Therapeutic drug monitoring is important in drugs for the treatment of substance-related disorders. Therefore, in this study, a new selective, very simple and rapid ultra-performance liquid chromatography-tandem mass spectrometer method was developed for the therapeutic drug monitoring of acamprosate. The developed method allows the determination of acamprosate in human plasma. The method was validated in terms of selectivity and linearity, which was in the range of 100-1,200 ng/ml for acamprosate. Intra-assay and inter-assay accuracy and precision were within the acceptable limits of the Eueopean Medicines Agency guideline. The lower limit of quantitation was 100 ng/ml for acamprosate. The developed method was successfully applied for therapeutic drug monitoring in patient plasma samples.

Fabrication of a molecularly imprinted polymer-based electrochemical sensor for the selective assay of antipsychotic drug clozapine and performance comparison with LC-MS/MS.

Clozapine (CLO) is an atypical antipsychotic drug indicated for the treatment of schizophrenia. The treatment effectiveness of CLO is better than that of other atypical antipsychotics, and it has the advantage of being able to determine its effectiveness by measuring its concentration in the patient's blood. Thus, sensitive, selective, and accurate determination of CLO in blood is highly significant for treatment monitoring. This study describes the design and fabrication of a molecularly imprinted polymer (MIP)-based electrochemical sensor for CLO determination. This is the first MIP-based electrochemical application in the literature for CLO determination. Employing the thermal polymerization approach, the MIP was formed on the glassy carbon electrode (GCE) using CLO as the template, trans-3-(3-Pyridyl)acrylic acid (3,3-TA) as the functional monomer, and the support of zinc oxide nanoparticles (ZnO NPs). Elaborate characterizations in terms of surface morphology and electrochemistry were performed via scanning electron microscopy (SEM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) methods. An indirect approach was employed to determine CLO in standard solution, real human biological samples, and tablet formulation, using 5 × 10-3 M [Fe(CN)6]3-/4- solution as the redox probe. The limit of detection (LOD) values for the standard solution and serum sample were calculated as 2.9 × 10-11 M and 6.01 × 10-12 M, respectively. These values and recovery studies confirmed the sensor's sensitivity and feasibility. The measurements in the presence of similarly structured compounds (olanzapine and quetiapine fumarate) verified the sensor's superior selectivity. Moreover, the developed sensor's performance was compared and verified using an LC-MS/MS method using the student's t-test and F-test.

A new method for the therapeutic drug monitoring of chlorpromazine in plasma by gas chromatography-mass spectrometry using dispersive liquid-liquid microextraction.

Background: Chlorpromazine is the first antipsychotic drug developed and is included in the list of 'essential drugs' prepared by the WHO. Therapeutic drug monitoring is an important point for psychotropic drugs because of significant genetic variability in their metabolism and poor compliance of the patients with treatment. Method: We developed a novel GC-MS method using dispersive liquid-liquid microextraction for the therapeutic monitoring of chlorpromazine. Results: The method was validated according to the European Medicines Agency guidelines. The developed method's lower limit of quantification was set as 30 ng/ml. The calibration curve of chlorpromazine was validated between 30 and 600 ng/ml, with correlation coefficients of more than 0.99. Conclusion: The developed method was applied to real human patient plasma.

A novel method for the therapeutic drug monitoring of biperiden in plasma by GC-MS using salt-assisted liquid-liquid microextraction.

Biperiden is an anticholinergic agent with central effects. It is used in Parkinson's syndromes and in the treatment of extrapyramidal symptoms that occur with the use of various agents (neuroleptics, antipsychotics). It causes anticholinergic syndrome in high doses. For this reason, therapeutic drug monitoring of biperiden is important. This study, it was aimed to develop a validated GC-MS method for the therapeutic monitoring of biperiden in human plasma. Biperiden and internal standard biperiden-d5 were extracted from plasma using the salt-assisted liquid-liquid extraction method. The method was validated according to the European Medicines Agency (EMA), Bioanalytical method validation guidelines. The lower limit of quantification of the developed method was chosen as 0.5 ng/mL. The calibration curve of biperiden for the method was validated between 0.5 and 15 ng/mL, showing correlation coefficients >0.99. In addition, the developed method was used for the therapeutic drug monitoring of biperiden in real patient plasma.

Hydrogen production using cocaine metabolite in microbial electrolysis cells.

In this study, the effects of cocaine metabolite, benzoylecgonine, commonly found in wastewater on hydrogen production were investigated using microbial electrolysis cells. Benzoylecgonine dissolved in synthetic urine and human urine containing benzoylecgonine were inoculated to evaluate hydrogen production performance in microbial electrolysis cells. Microbial electrolysis cells were inoculated with synthetic urine and human urine containing the cocaine metabolite benzoylecgonine for hydrogen gas production performance. Gas production was observed and measured daily by gas chromatography. GC-MS was used to analyze the compounds found in human urine before and after operation in microbial electrolysis cells. The metabolite's pH values and optical density in microbial electrolysis cells were analyzed spectrophotometrically. Hydrogen gas was successfully produced in microbial electrolysis cells (~ 5.5 mL) at the end of the 24th day in the presence of benzoylecgonine in synthetic urine. Human urine containing benzoylecgonine also generated hydrogen in microbial electrolysis cells. In conclusion, microbial electrolysis cells can be used to remove cocaine metabolites from contaminated wastewater generating hydrogen gas. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-023-03805-7.

Determination of Enzymatic Hydrolysis Efficiency in Detection of Cannabis Use by UPLC-MS-MS.

Cannabis is still the most widely used illegal plant in the world. However, cannabis use is prohibited in many countries. After cannabis use, Δ9-tetrahydrocannabinol is metabolized in the liver to 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THC-COOH) and most undergo glucuronidation. THC-COOH and THC-COOH glucuronide are excreted in the urine. The total concentration of THC-COOH in the urine sample is measured to determine cannabis use. The total concentration is determined after enzymatic or alkaline hydrolysis. In this study, comparing enzymatic hydrolysis efficiency is presented comprehensively together with the method developed for the determination of total THC-COOH in the urine. Also, the method was validated according to the European Medicines Agency Guidelines on bioanalytical method validation. The method has rapid hydrolysis time (20 min), rapid analysis time (5 min) and simple sample preparation. The lower limit of quantitation of the developed method was 1 ng/mL for THC-COOH. The calibration curve of THC-COOH was between 1 and 2,000 ng/mL with a correlation coefficient >0.99. Also, the method was applied to real patient's urine. We think that the results will provide a new perspective on enzymatic hydrolysis optimization studies.

Pharmacokinetic study of clarithromycin in human breast milk by UPLC-MS/MS.

This study aimed to develop a validated UPLC-MS/MS method for pharmacokinetic analysis of clarithromycin in human breast milk. For sample preparation, proteins precipitated with methanol and azithromycin were used as internal standards. Clarithromycin and azithromycin detection was achieved using electrospray ionization in positive mode. The chromatographic separation time was 5 min. The lower limit of quantification was 50 ng/mL. The calibration curve of clarithromycin was 50-4000 ng/mL, with a correlation coefficient> 0.99. The method was successfully applied to determine clarithromycin levels in breast milk obtained from a lactating mother after oral administration of a single tablet containing 500 mg of clarithromycin. The maximum human breast milk concentration (Cmax) was 3660 ng/mL, the time to reach the maximum concentration (tmax) was 2.5 h, and the area under curve (AUC0-24) was 18450 ng h/mL. The present study provides a novel UPLC-MS/MS method for pharmacokinetic analysis of clarithromycin in breast milk.

Determination of pethidine of abuse and relevant metabolite norpethidine in urine by ultra-performance liquid chromatography-tandem mass spectrometry.

Pethidine is an opiate agonist used orally and parenterally. Pethidine-containing drugs abuse is frequently encountered on health workers and patients. The analysis methods used to determine the abuse of pethidine are important for forensic toxicology. Pethidine is metabolized to norpethidine by the liver. Therefore, the determination of pethidine and norpethidine in urine is one of the methods to determine the abuse of pethidine. In this study, we have developed a precise, simple and rapid ultra-performance liquid chromatography-tandem mass spectrometer method for the determination of pethidine and norpethidine simultaneously. The developed method was validated in terms of selectivity and linearity which was in the range of 9-1800 ng/mL for both pethidine and norpethidine. The intra-assay and inter-assay accuracy and precision were found within acceptable limits of the EMA guideline. Lower limits of quantitation were 9 ng/mL for both pethidine and norpethidine. The developed method was successfully applied for the determination of both analytes in the real samples.

Chemical and molecular characterization of metabolites from Flavobacterium sp.

In this study, a Flavobacterium sp. is isolated from natural spring, and identified using molecular techniques. Extracellular and intracellular secondary metabolites are identified using solid phase microextraction gas chromatography-mass spectrometry and ultra performance liquid chromatography. Cytotoxic activity of the extracellular compounds produced by the Flavobacterium sp. and quercetin as the standard are measured using ECV304 human endothelial cells in vitro. Our results show that Flavobacterim sp. isolate has the highest percentage of similarity with Flavobacterium cheonhonense strain ARSA-15 (99%). Quercetin is detected as the major extracellular compound produced by the Flavobacterium sp. Methanol extract of Flavobacterium sp. resulted in a higher cell viability results when compared to DMSO extracts. Computational chemistry approach was used and it has been found that polar solvent (methanol) contributed to higher antioxidant activity. In conclusion, Flavobacterium sp. can be used to produce quercetin for industrial purposes.

Substance Abuse Profiles of Patients Admitted to the Alcohol and Drug Addiction Research, Treatment, and Education Center in Turkey.

OBJECTIVES: To determine the substance abuse profiles of patients treated a Drug Addiction Research, Treatment, and Education Center (AMATEM) in association with the percentage of substance use distribution and multiple substance use in their urine samples. For this, we retrospectively evaluated the urine sample analysis reports of 600 male and female patients aged 13 to 65 years who were treated at the AMATEM unit of Istanbul Neuropsychiatry Hospital between January 1st, 2015, and December 12th, 2015. MATERIALS AND METHODS: The urine samples were sent to Üsküdar University Advanced Toxicology Analysis Laboratory and were analyzed using a UPLC tandem mass spectrometer (UPLC-MS/MS). To determine the substance use profiles of the patients applying to AMATEM, statistical assessment was performed on the analysis reports of the patients. RESULTS: When the analysis reports of the 600 urine samples were examined, 293 patients were identified to have used addictive substances. The substances most frequently detected in the urine samples were respectively: cannabis, alcohol, morphine, cocaine, synthetic cannabinoids, 3,4-Methylenedioxymethamphetamine, and amphetamine. CONCLUSION: The findings in our study resemble the rates of cannabis use by the young population throughout the world. Our results show differences to the literature regarding the consumption of synthetic cannabinoids because the variety of synthetic cannabinoids change rapidly around the world each year.