scholarly journals Determination of Urinary Pterins by Capillary Electrophoresis Coupled with LED-Induced Fluorescence Detector

Molecules ◽  
2019 ◽  
Vol 24 (6) ◽  
pp. 1166 ◽  
Author(s):  
Wojciech Grochocki ◽  
Magdalena Buszewska-Forajta ◽  
Szymon Macioszek ◽  
Michał J. Markuszewski
Keyword(s):  
Capillary Electrophoresis ◽  
Limit Of Detection ◽  
Urine Samples ◽  
High Price ◽  
Range Limit ◽  
Uv Detector ◽  
Fluorescence Detector ◽  
Limit Of Quantification ◽  
Sample Stability

Urinary pterins have been found as potential biomarkers in many pathophysiological conditions including inflammation, viral infections, and cancer. However, pterins determination in biological samples is difficult due to their degradation under exposure to air, light, and heat. Besides, they occur at shallow concentration levels, and thus, standard UV detectors cannot be used without additional sample preconcentration. On the other hand, ultra-sensitive laser-induced fluorescence (LIF) detection can be used since pterins exhibit native fluorescence. The main factor that limits an everyday use of LIF detectors is its high price. Here, an alternative detector, i.e., light-emitted diode induced fluorescence (LEDIF) detector, was evaluated for the determination of pterins in urine samples after capillary electrophoresis (CE) separation. An optimized method was validated in terms of linearity range, limit of detection (LOD), limit of quantification (LOQ), intra- and interday precision and accuracy, sample stability in the autosampler, and sample stability during the freezing/thawing cycle. The obtained LOD (0.1 µM) and LOQ (0.3 µM) values were three-order of magnitude lower compared to UV detector, and two orders of magnitude higher compared to previously reported house-built LIF detector. The applicability of the validated method was demonstrated in the analysis of urine samples from healthy individuals and cancer patients.

scholarly journals A Stability Indicating UPLC Method for the Determination of Tramadol Hydrochloride: Application to Pharmaceutical Analysis

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Kanakapura B. Vinay ◽  
Hosakere D. Revanasiddappa ◽  
Cijo M. Xavier ◽  
Pavagada J. Ramesh ◽  
Madihalli S. Raghu
Keyword(s):  
Limit Of Detection ◽  
Potassium Dihydrogen Phosphate ◽  
Reversed Phase ◽  
Forced Degradation ◽  
Dihydrogen Phosphate ◽  
Uv Detector ◽  
Limit Of Quantification ◽  
Tramadol Hydrochloride ◽  
Stability Indicating

The use of Ultra Performance Liquid Chromatography (UPLC), with a rapid 5-minute reversed phase isocratic separation on a 1.7 μm reversed-phase packing material to provide rapid ‘‘high throughput’’ support for tramadol hydrochloride (TMH) is demonstrated. A simple, precise and accurate stability-indicating isocratic UPLC method was developed for the determination of TMH in bulk drug and in its tablets. The method was developed using Waters Aquity BEH C18 column (100 mm × 2.1 mm, 1.7 μm) with mobile phase consisting of a mixture of potassium dihydrogen phosphate buffer of pH 2.8 and an equal volume of acetonitrile (60 : 40 v/v). The eluted compound was detected at 226 nm with a UV detector. The standard curve of mean peak area versus concentration showed an excellent linearity over a concentration range 0.5–300 μg mL−1 TMH with regression coefficient (r) value of 0.9999. The limit of detection (S/N =3) was 0.08 μg mL−1 and the limit of quantification (S/N =10) was 0.2 μg mL−1. Forced degradation of the bulk sample was conducted an accordance with the ICH guidelines. Acidic, basic, hydrolytic, oxidative, thermal and photolytic degradation were used to assess the stability indicating power of the method. TMH was found to degrade significantly in acidic, basic and oxidative stress conditions and stable in thermal, hydrolytic and photolytic conditions.

scholarly journals Determination of Sulpiride by Capillary Electrophoresis with End-Column Electrogenerated Chemiluminescence Detection

2002 ◽  
Vol 48 (7) ◽  
pp. 1049-1058 ◽  
Author(s):  
Jifeng Liu ◽  
Weidong Cao ◽  
Haibo Qiu ◽  
Xiuhua Sun ◽  
Xiurong Yang ◽  
...  
Keyword(s):  
Capillary Electrophoresis ◽  
Human Plasma ◽  
Phosphate Buffer ◽  
Limit Of Detection ◽  
Extraction Procedure ◽  
Fused Silica ◽  
Urine Samples ◽  
Electrogenerated Chemiluminescence ◽  
Driving Voltage

Abstract Background: Capillary electrophoresis (CE) with tris(2,2′-bipyridyl)ruthenium(II) [Ru(bpy)32+]-electrogenerated chemiluminescence (ECL) detection is a promising method for clinical analysis. In this study, a method combining CE with Ru(bpy)32+ ECL (CE-ECL) detection that can be applied to amine-containing clinical species was developed, and the performance of CE-ECL as a quantitative method for determination of sulpiride in human plasma or urine was evaluated. Methods: Sulpiride was separated by capillary zone electrophoresis in uncoated fused-silica capillaries [50 cm × 25 μm (i.d.)] filled with phosphate buffer (pH 8.0) and a driving voltage of +15 kV, with end-column Ru(bpy)32+ ECL detection. A platinum disc electrode was used as working electrode. Sulpiride in human plasma or urine samples (100 μL) was extracted by a double-step liquid-liquid extraction procedure, dried under nitrogen at 35 °C in a water bath, and reconstituted with 100 μL of filtered water. The extraction solvent was ethyl acetate–dichloromethane (5:1 by volume). Results: Under optimum conditions (pH 8.0 phosphate buffer, injection for 6 s at 10 kV, and +1.2 V as detection potential), separation of sulpiride was accomplished within 4 min. The calibration curve was linear over a concentration range of 0.05–25.0 μmol/L, and the limit of detection was 2.9 × 10−8 mol/L for sulpiride. Intra- and interday CVs for ECL intensities were <6%. Extraction recoveries of sulpiride were 95.6–101% with CVs of 2.9–6.0%. The method was clinically validated for patient plasma and urine samples. Conclusions: CE combined with Ru(bpy)32+ ECL is reproducible, precise, selective, and enables the analysis of sulpiride in human plasma and urine. It thus is of value for rapid and efficient analysis of amine-containing analytes of clinical interest.

scholarly journals Development and Validation of Sibutramine Determination in Drug Products by Capillary Electrophoresis

2020 ◽  
Vol 9 (4) ◽  
pp. 141-145
Author(s):  
A. M. Sukhanova ◽  
I. B. Perova ◽  
K. I. Eller ◽  
G. M. Rodioinova ◽  
S. V. Chernova ◽  
...  
Keyword(s):  
Capillary Electrophoresis ◽  
Quantitative Determination ◽  
Limit Of Detection ◽  
Array Detector ◽  
Diode Array ◽  
Diode Array Detector ◽  
Limit Of Quantification ◽  
Drug Products ◽  
Development And Validation

Introduction. Recently, there has been a growing trend in the number of obese and overweight patients. To date, sibutramine is the most effective drug for treating obesity and overweight. The drug is an inhibitor of the reuptake of serotonin and norepinephrine, which leads to a decrease in hunger, and therefore, to weight loss.Aim. To develop and validate a methodology for the determination of sibutramine in drugs by capillary electrophoresis (CE) using an ultraviolet diode array detector.Materials and methods. Quantitative determination of sibutramine in drugs was carried out using the CE method with an ultraviolet diode array detector. A solution of phosphate buffer 50 mmol pH = 7.0 was used as a solvent and working electrolyte; to separate the peaks – quartz capillary 56 cm, 50 μm.Results and discussion. The developed method was validated according to the following parameters: specificity, linearity, correctness, precision, limit of detection and limit of quantification.Conclusion. A method for the quantitative determination of sibutramine in drugs by the CE method using an ultraviolet diode array detector has been developed and validated. This method meets all the requirements of General Pharmacopoeia Monograph 1.1.0012.15 «Validation of the analytical method» and can be used to control the quality of drugs, the active pharmaceutical substance of which is sibutramine.

scholarly journals Design and Functionalization of a µPAD for the Enzymatic Determination of Nitrate in Urine

Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6355
Author(s):  
Francisca T. S. M. Ferreira ◽  
Raquel B. R. Mesquita ◽  
António O. S. S. Rangel
Keyword(s):  
Limit Of Detection ◽  
Colorimetric Detection ◽  
Enzymatic Reaction ◽  
Urine Samples ◽  
Griess Reagent ◽  
Limit Of Quantification ◽  
Enzymatic Determination ◽  
Vacuum Atmosphere ◽  
Nitrate Determination

In this work, the design of a microfluidic paper-based analytical device (μPAD) for the quantification of nitrate in urine samples was described. Nitrate monitoring is highly relevant due to its association to some diseases and health conditions. The nitrate determination was achieved by combining the selectivity of the nitrate reductase enzymatic reaction with the colorimetric detection of nitrite by the well-known Griess reagent. For the optimization of the nitrate determination μPAD, several variables associated with the design and construction of the device were studied. Furthermore, the interference of the urine matrix was evaluated, and stability studies were performed, under different conditions. The developed μPAD enabled us to obtain a limit of detection of 0.04 mM, a limit of quantification of 0.14 mM and a dynamic concentration range of 0.14–1.0 mM. The designed μPAD proved to be stable for 24 h when stored at room temperature in air or vacuum atmosphere, and 60 days when stored in vacuum at −20 °C. The accuracy of the nitrate μPAD measurements was confirmed by analyzing four certified samples (prepared in synthetic urine) and performing recovery studies using urine samples.

Capillary Electrophoresis Method for Determination of Escitalopram Oxalate in Urine Samples and Different Dosage Forms

2020 ◽  
Vol 58 (8) ◽  
pp. 759-769
Author(s):  
Wafa F S Badulla ◽  
Arın G Dal Poçan ◽  
Zeki Atkoşar ◽  
Göksel Arlı
Keyword(s):  
Capillary Electrophoresis ◽  
Limit Of Detection ◽  
Background Electrolyte ◽  
Dosage Forms ◽  
Fused Silica ◽  
Urine Samples ◽  
Effective Length ◽  
Simple Liquid ◽  
Pharmaceutical Dosage Forms

Abstract Application of capillary electrophoresis (CE) has become a rapidly growing analytical technique for the estimation of drugs in pharmaceutical dosage forms and biological fluids. In this study, an effective and sensitive method was developed for the determination of escitalopram oxalate (ESC-OX) by CE with diode-array detection at 200 nm. The separation was achieved by a fused silica capillary with 40 cm effective length (48.5 cm total, 75 μm i.d.). The background electrolyte was composed of 15 mM phosphate buffer (pH 2.5). The applied potential was 22.5 kV, and the samples were injected at 50 mbar pressure for 10 s. Metoprolol was used as an internal standard (IS). The migration time under these optimum conditions was 6.51 ± 0.07 and 6.73 ± 0.08 min for ESC-OX and IS, respectively, with total run time 7 min. The method was validated for linearity, precision, accuracy, specificity and sensitivity. The limit of detection was calculated as 3.85 and 5.07 ng mL−1 for standard and urine samples, respectively. The developed method was employed successfully for the determination of ESC-OX in different pharmaceutical dosage forms and spiked human urine after simple liquid–liquid extraction with good recovery.

scholarly journals Development of a HPLC-UV method for determination of meloxicam in human plasma and pharmaceutical dosage forms

2014 ◽  
Vol 60 (4) ◽  
pp. 142-145 ◽  
Author(s):  
Csifo Enikő ◽  
Croitoru M. D. ◽  
Fülöp Ibolya ◽  
Muntean Daniela-Lucia
Keyword(s):  
Human Plasma ◽  
Limit Of Detection ◽  
Low Cost ◽  
Extraction Procedure ◽  
Dosage Forms ◽  
Composition Gradient ◽  
Range Limit ◽  
Limit Of Quantification ◽  
Pharmaceutical Dosage Forms

Abstract Objectives: A simple, quick and low cost HPLC-UV method for assay of meloxicam in plasma and pharmaceutical dosage forms was developed. Methods: Separation and assay of meloxicam, using a simple reverse phase HPLC-UV method was achieved using an Agilent Zorbax SB C18 column, with methanol and 1% aqueous solution of glacial acetic acid as mobile phase. Elution was performed with composition gradient, meloxicam being detected at 355 nm with a 5 minutes analysis time. The method was tested on human plasma and pharmaceutical dosage forms. Results: The retention time of the meloxicam was 3,7 minutes. Regression analysis showed good linearity, with correlation coefficient R= 0,9997; linear regression equation: y = 206,1x -77,5 over the 20-2000 ng/ml concentration range. Limit of detection was determined to be 5 ng/ml and limit of quantification was set at 15 ng/ml. The recovery of the analyte in human plasma was low: 30,50%, however it was reproducible, with a coefficient of variation of 4,83%. The analysis of the tablets resulted in a 85,82% of meloxicam compared to the declared concentration. Conclusions: The method proposed is quick, simple and adequate for detecting the meloxicam in human plasma. Although the recovery rate was low, it was reproducible, which leads to the fact, that improving extraction procedure can optimize the method.

scholarly journals Development and Validation of Stability-Indicating RP-UPLC Method for the Determination of Methdilazine in Bulk Drug and in Pharmaceutical Dosage Form

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Madihalli S. Raghu ◽  
Kanakapura Basavaiah ◽  
Cijo M. Xavier ◽  
Kudige N. Prashanth
Keyword(s):  
Limit Of Detection ◽  
Bulk Sample ◽  
Reversed Phase ◽  
Forced Degradation ◽  
Uv Detector ◽  
Limit Of Quantification ◽  
Pharmaceutical Dosage Form ◽  
Stability Indicating ◽  
Bulk Drug

A simple, precise, and accurate, and stability-indicating isocratic Ultraperformance Liquid Chromatography (UPLC) method was developed for the determination of methdilazine hydrochloride (MDH) in bulk drug and in its tablets. The use of UPLC, with a rapid 5-minute-reversed-phase isocratic separation on a 1.7 μm reversed-phase packing material to provide rapid ‘‘high throughput’’ support for MDH, is demonstrated. The method was developed using Waters Acquity BEH C18 column (100 mm × 2.1 mm, 1.7 μm) with mobile phase consisting of a mixture of potassium dihydrogenorthophosphate and 1-pentane sulphonic acid buffer of pH 4.0 and acetonitrile (60 : 40 v/v). The eluted compound was detected at 254 nm with a UV detector. The standard curve of mean peak area versus concentration showed an excellent linearity over a concentration range 0.5–80 μg mL−1 MDH with regression coefficient () value of 0.9999. The limit of detection () was 0.2 μg mL−1 and the limit of quantification () was 0.5 μg mL−1. Forced degradation of the bulk sample was conducted in accordance with the ICH guidelines. Acidic, basic, hydrolytic, oxidative, thermal, and photolytic degradations were used to assess the stability indicating power of the method. The drug was found to be stable in acidic, basic, thermal, hydrolytic, and photolytic stress conditions and showed slight degradation in oxidative stress condition.

HPLC DETERMINATION OF N-METHYLETHANOLAMINE IN DIPHENHYDRAMINE HYDROCHLORIDE DRUG SUBSTANCE BY PRE-COLUMN DERIVATIZATION

INDIAN DRUGS ◽  
2018 ◽  
Vol 55 (10) ◽  
pp. 56-62
Author(s):  
A Anerao ◽  
◽  
V. Dighe ◽  
A Gupta ◽  
C. Patil ◽  
...  
Keyword(s):  
High Performance ◽  
Limit Of Detection ◽  
Active Pharmaceutical Ingredient ◽  
Hplc Method ◽  
Uv Detector ◽  
Limit Of Quantification ◽  
Chromatography Method ◽  
Diphenhydramine Hydrochloride ◽  
Liquid Chromatography Method

N-Methylethanolamine is the side chain of the drug diphenhydramine hydrochloride. A sensitive high performance liquid chromatography method with pre-column derivatization was developed and validated for the determination of N-methylethanolamine impurity in diphenhydramine hydrochloride active pharmaceutical ingredient. HPLC method on column Cosmosil MS-II, C-18, 250 mm X 4.6 mm, particle size 5 μm with UV detector was used. The proposed method is specific, linear, accurate, rugged and precise. The calibration curves showed good linearity over the concentration range of 0.03 mg/g to 1.5 mg/g and the correlation coefficient was 0.999. Method had very low limit of detection (LOD) and limit of quantification (LOQ) as 0.01 mg/g and 0.03 mg/g, respectively, of the analyte. Accuracy was observed within 94.4% to 96.2%.

scholarly journals Measurement of Glutathione as a Tool for Oxidative Stress Studies by High Performance Liquid Chromatography

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4196
Author(s):  
Faisal Nuhu ◽  
Andrew Gordon ◽  
Roger Sturmey ◽  
Anne-Marie Seymour ◽  
Sunil Bhandari
Keyword(s):  
Oxidative Stress ◽  
High Performance ◽  
Limit Of Detection ◽  
Kidney Diseases ◽  
Biological Tissues ◽  
Clinical Samples ◽  
Range Limit ◽  
Limit Of Quantification ◽  
Reliable Determination

Background: Maintenance of the ratio of glutathione in the reduced (GSH) and oxidised (GSSG) state in cells is important in redox control, signal transduction and gene regulation, factors that are altered in many diseases. The accurate and reliable determination of GSH and GSSG simultaneously is a useful tool for oxidative stress determination. Measurement is limited primarily to the underestimation of GSH and overestimation GSSG as a result of auto-oxidation of GSH. The aim of this study was to overcome this limitation and develop, optimise and validate a reverse-phase high performance liquid chromatographic (HPLC) assay of GSH and GSSG for the determination of oxidant status in cardiac and chronic kidney diseases. Methods: Fluorescence detection of the derivative, glutathione-O-pthaldialdehyde (OPA) adduct was used. The assay was validated by measuring the stability of glutathione and glutathione-OPA adduct under conditions that could affect the reproducibility including reaction time and temperature. Linearity, concentration range, limit of detection (LOD), limit of quantification (LOQ), recovery and extraction efficiency and selectivity of the method were assessed. Results: There was excellent linearity for GSH (r2 = 0.998) and GSSG (r2 = 0.996) over concentration ranges of 0.1 µM–4 mM and 0.2 µM–0.4 mM respectively. The extraction of GSH from tissues was consistent and precise. The limit of detection for GSH and GSSG were 0.34 µM and 0.26 µM respectively whilst their limits of quantification were 1.14 µM and 0.88 µM respectively. Conclusion: These data validate a method for the simultaneous measurement of GSH and GSSG in samples extracted from biological tissues and offer a simple determination of redox status in clinical samples.

scholarly journals Simultaneous determination of phytoestrogens in dietary supplements by high-performance liquid chromatography

2021 ◽  
Vol 4 (3) ◽  
pp. 24-35
Author(s):  
Thanh An Vu Thi ◽  
Thanh Hoa Mac Thi ◽  
Khanh Cao Cong ◽  
◽  
◽  
...  
Keyword(s):  
Dietary Supplements ◽  
Mobile Phase ◽  
High Performance ◽  
Limit Of Detection ◽  
Ultrasonic Method ◽  
Gradient Elution ◽  
Analysis Procedure ◽  
Range Limit ◽  
Limit Of Quantification

The bio-active phytoestrogen compounds (puerarin, daidzin, glycitin, genistin, miroestrol, daidzein, glycitein, genistein) in dietary supplements were extracted by ultrasonic method with methanol solvent in 40oC. The analysis procedure was carried out on HPLC Alliance e2695 (Waters) system, with RP-C18 Reliant (25 mm × 4.6 mm; 5µm) column, at 30oC. Phytoestrogens were separated by using gradient elution with a mobile phase consisting 0.1% (v/v) phosphoric aqueous solution and methanol in 45 minutes. The method was validated by determining its specificity, linear range, limit of detection, limit of quantification, repeatability and accuracy. This method was applied succesfully to determine content of Phytoestrogens in commercial dietary supplement products.

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