scholarly journals Determination of Dialkyl Phosphates as Breakdown Products of Organophosphorus Insecticides in Fruit Juices by HPTLC with Fluorescence Detection

2009 ◽  
Vol 92 (3) ◽  
pp. 691-698 ◽  
Author(s):  
Wolfgang Schwack ◽  
Tatjana Zeisler ◽  
Constanze Stiefel
Keyword(s):  
Apple Juice ◽  
Degradation Products ◽  
Organophosphorus Pesticides ◽  
Internal Standard ◽  
Barium Chloride ◽  
Fruit Juices ◽  
Limit Of Quantification ◽  
Dimethyl Phosphate ◽  
Relative Standard

Abstract Dialkyl phosphates (DAP) are common degradation products of organophosphorus pesticides that are used as urinary biomarkers for human exposure. An HPTLC method was developed for the quantitative determination of DAP in fruit juices, i.e., dimethyl phosphate (DMP), dimethyl thiophosphate (DMTP), diethyl phosphate (DEP), and diethyl thiophosphate (DETP). Dibutyl phosphate (DBP) was used as an internal standard. The method was based on precipitation of fruit acids in the presence of barium chloride and acetonitrile and liquidliquid extraction with acetonitrilediethyl ether. Extracted DAP were derivatized with 1-(bromoacetyl)pyrene (BAP), and the BAP derivatives separated on HPTLC amino plates with dichloromethane as the mobile phase. Densitometry was performed by measurement of fluorescence at 366/>400 nm. The limit of quantification (LOQ) values were between 0.8 and 1.4 ng/zone. Fluorescence enhancement was achieved by dipping the plate into a paraffin oil solution, increasing the sensitivity and resulting in an LOQ of 0.50.6 ng/zone. Repeatabilities with relative standard deviations of 3.5 (n = 5, at 1520 ng/zone) and coefficients of correlation of 0.9999 were highly satisfactory for rapid trace analysis of DAP in the fruit juices by HPTLC. The mean recoveries from apple juice spiked at 0.5 mg/L were 74, 83, 70, and 57 for DMP, DEP, DMTP, and DETP, respectively. If an application volume of 5 L of apple juice extract was applied, the LOQ in apple juice was 300 g/L. However, this can be lowered by application of higher volumes (up to 50 L) or a more concentrated derivatization batch.

ICH/FDA Guidelines-Compliant Validated Stability-Indicating HPLC-UV Method for the Determination of Axitinib in Bulk and Dosage Forms

2020 ◽  
Vol 16 (8) ◽  
pp. 1106-1112
Author(s):  
Ibrahim A. Darwish ◽  
Nasr Y. Khalil ◽  
Mohammad AlZeer
Keyword(s):  
High Performance ◽  
Kinase Inhibitor ◽  
Degradation Products ◽  
Internal Standard ◽  
Dosage Forms ◽  
Uv Detector ◽  
Stability Indicating ◽  
Therapeutic Benefits ◽  
Relative Standard

Background: Axitinib (AXT) is a member of the new generation of the kinase inhibitor indicated for the treatment of advanced renal cell carcinoma. Its therapeutic benefits depend on assuring the good-quality of its dosage forms in terms of content and stability of the pharmaceutically active ingredient. Objective: This study was devoted to the development of a simple, sensitive and accurate stabilityindicating high-performance liquid chromatographic method with ultraviolet detection (HPLC-UV) for the determination of AXT in its bulk and dosage forms. Methods: Waters HPLC system was used. The chromatographic separation of AXT, internal standard (olaparib), and degradation products were performed on the Nucleosil CN column (250 × 4.6 mm, 5 μm). The mobile phase consisted of water:acetonitrile:methanol (40:40:20, v/v/v) with a flow rate of 1 ml/min, and the UV detector was set at 225 nm. AXT was subjected to different accelerated stress conditions and the degradation products, when any, were completely resolved from the intact AXT. Results: The method was linear (r = 0.9998) in the concentration range of 5-50 μg/ml. The limits of detection and quantitation were 0.85 and 2.57 μg/ml, respectively. The accuracy of the method, measured as recovery, was in the range of 98.0-103.6% with relative standard deviations in the range of 0.06-3.43%. The results of stability testing revealed that AXT was mostly stable in neutral and oxidative conditions; however, it was unstable in alkaline and acidic conditions. The kinetics of degradation were studied, and the kinetic rate constants were determined. The proposed method was successfully applied for the determination of AXT in bulk drug and dosage forms. Conclusions: A stability-indicating HPLC-UV method was developed and validated for assessing AXT stability in its bulk and dosage forms. The method met the regulatory requirements of the International Conference on Harmonization (ICH) and the Food and Drug Administration (FDA). The results demonstrated that the method would have great value when applied in quality control and stability studies for AXT.

Development and Validation of a New Method for the Determination of Anti-hepatitis C Agent Simeprevir in Human Plasma using HPLC with Fluorescence Detection

2020 ◽  
Vol 16 (4) ◽  
pp. 428-435
Author(s):  
Ahmed F.A. Youssef ◽  
Yousry M. Issa ◽  
Kareem M. Nabil
Keyword(s):  
Hepatitis C ◽  
Human Plasma ◽  
Fluorescence Detection ◽  
Internal Standard ◽  
Protein Precipitation ◽  
Assay Method ◽  
Fluorescence Detector ◽  
Limit Of Quantification ◽  
Relative Standard

Background: Simeprevir is one of the recently discovered drugs for treating hepatitis C which is one of the major diseases across the globe. Objective: The present study involves the development of a new and unique High-Performance Liquid Chromatography (HPLC) method using fluorescence detection for the determination of simeprevir (SIM) in human plasma. Methods: Two methods of extractions were tested, protein precipitation using acetonitrile and liquidliquid extraction. A 25 mM dipotassium hydrogen orthophosphate (pH 7.0)/ACN (50/50; v/v), was used as mobile phase and C18 reversed phase column as the stationary phase. The chromatographic conditions were optimized and the concentration of simeprevir was determined by using the fluorescence detector. Cyclobenzaprine was used as an internal standard. Results: Recovery of the assay method based on protein precipitation was up to 100%. Intra-day and inter-day accuracies range from 92.30 to 107.80%, with Relative Standard Deviation (RSD) range 1.65-8.02%. The present method was successfully applied to a pharmacokinetic study where SIM was administered as a single dose of 150 mg SIM/capsule (Olysio®) to healthy individuals. Conclusion: This method exhibits high sensitivity with a low limit of quantification 10 ng mL-1, good selectivity using fluorescence detection, wide linear application range 10-3000 ng mL-1, good recovery and highly precise and validation results. The developed method can be applied in routine analysis for real samples.

scholarly journals Quantitative Determination of Azithromycin in Human Plasma by Liquid Chromatography–Mass Spectrometry and its Application in Pharmackokinetic Study

2012 ◽  
Vol 11 (1) ◽  
pp. 55-63 ◽  
Author(s):  
Maizbha Uddin Ahmed ◽  
Mohammad Safiqul Islam ◽  
Tasmin Ara Sultana ◽  
AGM Mostofa ◽  
Muhammad Shahdaat Bin Sayeed ◽  
...  
Keyword(s):  
Mobile Phase ◽  
Solid Phase ◽  
Internal Standard ◽  
Extraction Process ◽  
Serum Samples ◽  
Limit Of Quantification ◽  
Relative Standard ◽  
Linear Concentration Range ◽  
Linear Concentration

Azithromycin is an effective and well-known antimicrobial agent. In the present study, a simple, sensitive and specific LC/MS/MS method has been developed and validated for the quantification of Azithromycin in  human serum samples using Clarithromycin as internal standard. Azithromycin was extracted from biological matrix  by using solid phase extraction process. The chromatographic separation was performed on Luna C18 (3 ?, 2x150   mm) column with a mobile phase consisting of 35 mM ammonium acetate buffer (mobile phase-A) and acetonitrile  and methanol in ratio of 90:10 ( as mobile phase-B) at a flow rate of 0.25 mL/min. The method was validated over a  linear concentration range of 0.5?50.0 ng/mL and limit of quantification (LOQ) was 0.5 ng/mL with a coefficient of  correlation (r2) = 0.9998. The intra-day and inter-day precision expressed as relative standard deviation were 1.64% – 8.43% and 2.32% – 9.92%, respectively. The average recovery of azithromycin from serum was 98.11%. The method  was successfully applied to a pharmacokinetic study after oral administration of Azithromycin 200 mg/5 ml suspension in healthy Bangladeshi volunteers. DOI: http://dx.doi.org/10.3329/dujps.v11i1.12488 Dhaka Univ. J. Pharm. Sci. 11(1): 55-63, 2012 (June)

Development and Validation of a Quantitative NMR Method for the Determination of the Commercial Tablet Formulation of Sulfasalazine

2018 ◽  
Vol 15 (1) ◽  
pp. 39-44 ◽  
Author(s):  
Feng Su ◽  
Zi-qing Sun ◽  
Xian-rui Liang
Keyword(s):  
Maleic Acid ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Tablet Formulation ◽  
Quantitative Nmr ◽  
Limit Of Quantification ◽  
Relative Standard ◽  
Development And Validation ◽  
Good Agreement

Introduction: Quantitative NMR spectroscopy (qNMR) is a rapid, simple and efficient method for the assay of sulfasalazine (SSZ) in commercial tablet formulation. Materials and Methods: The qNMR method was demonstrated using maleic acid as an internal standard and DMSO-d6 as a solvent. The characteristic signals of SSZ at δ 8.36 ppm and maleic acid at δ 6.28 ppm were quantified. The reliability of the quantification method had been implemented successfully in validated experiments including specificity and selectivity, linearity, recovery, precision concentration rang, limit of detection (LOD), limit of quantification (LOQ), stability and robustness. Conclusion: The method was found to be liner (R2 = 0.9991) from 8.62 to 20.14 mg/0.6 mL DMSO-d6 in the drug concentration range. The maximum relative standard deviation (RSD) of recovery and precision were tested to be 0.59% and 0.65%, respectively. The LOD and LOQ were determined to be 0.02, 0.07 mg/mL, respectively. The RSD of stability was 0.05%. The robustness was demonstrated by changing four different parameters with the maximum difference less than 0.9%. In addition, the result of qNMR showed in good agreement with the HPLC and UV methods. Based on the experiments, the developed method was successfully applied to the determination of SSZ in commercial tablet.

scholarly journals Validation and Optimization of a Simple RP-HPLC Method for the Determination of Paracetamol in Human Serum and its Application in a Pharmacokinetic Study with Healthy Bangladeshi Male Volunteers

2015 ◽  
Vol 13 (2) ◽  
pp. 125-131
Author(s):  
Anisa Alam Tanam ◽  
Mohammad Firoz Khan ◽  
Ridwan Bin Rashid ◽  
Md Zakir Sultan ◽  
Mohammad A Rashid
Keyword(s):  
Human Serum ◽  
Pharmacokinetic Study ◽  
Internal Standard ◽  
Immediate Release ◽  
Hplc Method ◽  
Serum Samples ◽  
Limit Of Quantification ◽  
Rp Hplc ◽  
Relative Standard

Acetaminophen (paracetamol) is an analgesic and antipyretic agent with minimum anti-inflammatory properties. In the present study a simple, fast, accurate, precise and reproducible RP-HPLC method has been developed and validated for the quantification of paracetamol in human serum samples using theophylline as internal standard. Protein precipitation with perchloric acid was employed in the extraction of paracetamol and theophylline from biological matrix. The chromatographic separation was accomplished on Phenomenex C18 column with a mobile phase comprising of 0.05 mM sodium sulfate buffer (pH 2.2 ± 0.02 adjusted with phosphoric acid) and acetonitrile at a ratio of 93:7 at a flow rate of 1.0 ml/min. The chromatogram was monitored by UV detection at a wavelength of 254 nm. The method was validated over a linear concentration range of 2-100 ?g/ml and limit of quantification (LOQ) was 1.61 ?g/ml with a correlation coefficient (r2) 0.997. The intra-day and inter-day precision expressed as relative standard deviation were found to be 0.49 - 2.68% and 0.36 - 3.44%, respectively. The average recovery of paracetamol from serum ranged from 99.0 - 106.4%. The method was successfully applied to a pharmacokinetic study after oral administration of immediate release paracetamol tablet (1000 mg) in four healthy Bangladeshi volunteers. The mean Cmax was found to be 11.03 ± 3.21 ?g/ml, which occurred at Tmax of 0.88 ± 0.14 hr. The half life, AUC0-8 and AUC0-? values were found to be 3.09 ± 0.71 hr, 31.06 ± 6.57 hr-?g/ml and 37.92 ± 9.51 hr- ?g/ml, respectively. DOI: http://dx.doi.org/10.3329/dujps.v13i2.21889 Dhaka Univ. J. Pharm. Sci. 13(2): 125-131, 2014 (December)

scholarly journals Application of High Performance Liquid Chromatography to the Analysis of Pesticide Residues in Apple Juice

2018 ◽  
Vol 67 (1) ◽  
pp. 93-102 ◽  
Author(s):  
Lenche Velkoska-Markovska ◽  
Biljana Petanovska-Ilievska ◽  
Aleksandar Markovski
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Pesticide Residues ◽  
High Performance ◽  
Apple Juice ◽  
Solid Phase ◽  
Limit Of Quantification ◽  
Relative Standard ◽  
Standard Deviations

Summary The modern apple production involves the use of large amounts of pesticides that can be found in processed products such as apple juice. Harmful effects of pesticide residues on humans, especially children, are well known, hence the content of pesticide residues in fruit, vegetables and their juices should be controlled. This study presents an application of a new, relatively simple and reliable analytical method for qualitative and quantitative determination of three organophosphorus and one organonitrogen pesticide residues in apple juices. The analysis utilizes reversed-phase high-performance liquid chromatography (RP-HPLC) followed by UV diode array detection. Prior to HPLC analysis, a solid-phase extraction (SPE) was used for analytes concentration and sample clean-up. Specificity, selectivity, linearity, precision, accuracy and limit of quantification (LOQ) were examined to assess the validity of the developed method. The method had satisfactory values of multiple correlation coefficients for calibration curves (R2 ≥ 0.95 ). The precision was evaluated for the retention times and peak areas, and the estimated values for relative standard deviations (RSD) were 0.05 % - 0.18 % and 0.09 % - 0.62 %, respectively, which indicated an excellent precision of the proposed method. Under the established conditions, the recovery of analytes was 93.80 % - 119.41 %, with relative standard deviations below 0.56 %. This method was successfully applied for determination of some organophosphorus and organonitrogen pesticide residues in apple juices which were taken from Macedonian markets. The achieved values for LOQs were low enough compared to the MRLs of the investigated pesticides in apple according to the Regulation (EC) No 396/2005. Detectable residues of the examined pesticides were not found in the analyzed samples.

scholarly journals Development and validation of a GC–MS method for the simultaneous determination of acetochlor, fluorochloridone, and pendimethalin in a herbicide emulsifiable concentrate formulation

2020 ◽  
Vol 32 (4) ◽  
pp. 238-241 ◽  
Author(s):  
Dandan Wang ◽  
Shengde Wu
Keyword(s):  
Internal Standard ◽  
Ternary Mixtures ◽  
Gas Chromatography Mass Spectrometry ◽  
Selected Ion Monitoring ◽  
Limit Of Quantification ◽  
Emulsifiable Concentrate ◽  
Relative Standard ◽  
Replicate Measurements ◽  
Development And Validation

This paper describes a rapid method to simultaneously determine acetochlor, fluorochloridone and pendimethalin present in a herbicide emulsifiable concentrate (EC) formulation using gas chromatography–mass spectrometry (GC–MS). Selected ion monitoring mode was performed to increase the sensitivity, with dibutyl phthalate as an internal standard. The method was validated with respect to linearity, accuracy, precision, and stability. Chromatographic separation was carried out on a TG-5 MS column (30 m × 0.25 mm × 0.25 μm) with helium as the carrier gas at a flow rate of 1.0 mL/min. Calibration curves were linear over 2.0–20.0 μg/mL for each analyte, and the limit of quantification was below 20 ng/mL. Good performance in terms of recovery ranging from 94.5% to 102.5% at 3 concentration levels proved excellent accuracy. The intra- and inter-day relative standard deviations for 6 replicate measurements were always less than 5%. The developed method is simple and efficient for the routine determination of the ternary mixtures in a compound herbicide EC formulation product.

scholarly journals Development and Validation of Simple RP-HPLC Method for Intracellular Determination of Fluconazole Concentration and Its Application to the Study ofCandida albicansAzole Resistance

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Tigran K. Davtyan ◽  
Levon A. Melikyan ◽  
Nune A. Nikoyan ◽  
Hripsime P. Aleksanyan ◽  
Nairi G. Grigoryan
Keyword(s):  
High Performance ◽  
Internal Standard ◽  
Gradient Elution ◽  
Drug Susceptibility ◽  
Intracellular Concentration ◽  
Limit Of Quantification ◽  
Rp Hplc ◽  
Microbiological Methods ◽  
Relative Standard

Candida albicans(strains NCTC-885-653 and ATCC-10231) long-term cultivated in the presence of antifungal agent fluconazole (FLC) and classical microbiological methods for determination of minimal inhibitory concentration (MIC) were used in this study. A simple and sensitive method based on reverse-phase high-performance liquid chromatography (RP-HPLC) has been developed for the determination of FLC intracellular concentration inC. albicansusing tinidazole as an internal standard. Following extraction with dichloromethane, the chromatographic separation was achieved on a Machery-Nagel EC250/2 Nucleodur-100-3 C18 column by gradient elution using the mobile phase consisting of (A) 0.01 M ammonium acetate buffer, pH = 5.00, and (B) acetonitrile. Different analytical performance parameters such as linearity, precision, accuracy, limit of quantification (LOQ), and robustness were determined according to US DHHS FDA and EMEA guidelines. The method was linear for FLC(r=0.9999)ranging from 100 to 10000 ng/mL. The intraday and interday precisions (relative standard deviation) were within 2.79 and 2.64%, respectively, and the accuracy (relative error) was less than 2.82%. The extraction recovery ranged from 79.3 to 85.5%. The reliable method was successfully applied toC. albicansazole-resistance study and it was shown that intracellular concentration of FLC correlated with a yeast drug susceptibility profile and MIC values.

scholarly journals GAS CHROMATOGRAPHIC DETERMINATION OF 23 ORGANOPHOSPHORUS PESTICIDES RESIDUE IN BOTTLE GUARD MATRIX

2018 ◽  
Vol 10 (1) ◽  
pp. 53
Author(s):  
Sudeep Mishra ◽  
Lalitesh Kr. Thakur ◽  
Neelam Richhariya
Keyword(s):  
Limit Of Detection ◽  
Organophosphorus Pesticides ◽  
Chromatographic Determination ◽  
Limit Of Quantification ◽  
Relative Standard ◽  
Residue Levels ◽  
The Mean ◽  
Pesticides Residue ◽  
Chromatographic Mass

Objective: To validate in-house QuEChERS method, which scrutinizes and quantify the residue levels of some most frequently used organophosphorus pesticides and to prove a complete workflow for routine multi-residue pesticide analysis in representative bottle guard matrices and study the persistence of 23 organ phosphorus pesticides.Methods: QuEChERS (quick, easy, cheap, effective, rugged and safe) extraction method was followed. Method validation and residue screening of bottle guard samples were conducted by GC-FPD (Gas Chromatography-Flame Photometric Detector) were used to analyse the presence of pesticides whereas confirmation of pesticides was done by GC-MS (Gas Chromatographic-Mass Spectrometer). Results: For bottle guard matrix, LOD (limit of detection) and LOQ (limit of quantification) values are lowest for phorate (0.005 mg/kg and 0.015 mg/kg) and highest for parathion-methyl (0.1 mg/kg and 0.3 mg/kg) respectively. Calibration curve, was plotted between an area of 23 pesticide standard mixture against seven different concentration levels of 0.01, 0.02, 0.05, 0.10, 0.20, 0.50, 1.00 mg/kg with regression coefficient (R2) are in the range of 0.978-0.994. The mean recovered amount at 0.05 mg/kg spikeing concentration are in the range of lowest 0.0413 mg/kg to highest 0.0467 mg/kg and relative standard deviation are in the range of lowest 2.2 to highest 8.571.Conclusion: For ensuring exposure to contaminants, especially by dietary intake, Robust analytical methods were validated for carrying out both research and monitoring programmes and thus for defining limitations and supporting enforcement of regulations.

Stability Indicating Liquid Chromatographic Method for the Determination of Fenofibrate and its Application to Kinetic Studies

2013 ◽  
Vol 5 (4) ◽  
pp. 1866-1874
Author(s):  
K. Srinivasa Rao ◽  
Keshar N K ◽  
N Jena ◽  
M.E.B Rao ◽  
A K Patnaik
Keyword(s):  
Degradation Products ◽  
Kinetic Studies ◽  
Pharmaceutical Formulations ◽  
Assay Method ◽  
Pharmaceutical Dosage Form ◽  
Stability Indicating ◽  
Zero Order Kinetics ◽  
Relative Standard ◽  
Liquid Chromatographic

A stability-indicating LC assay method was developed for the quantitative determination of fenofibrate (FFB) in pharmaceutical dosage form in the presence of its degradation products and kinetic determinations were evaluated in acidic, alkaline and peroxide degradation conditions. Chromatographic separation was achieved by use of Zorbax C18 column (250 × 4.0 mm, 5 μm). The mobile phase was established by mixing phosphate buffer (pH adjusted 3 with phosphoric acid) and acetonitrile (30:70 v/v). FFB degraded in acidic, alkaline and hydrogen peroxide conditions, while it was more stable in thermal and photolytic conditions. The described method was linear over a range of 1.0-500 μg/ml for determination of FFB (r= 0.9999). The precision was demonstrated by relative standard deviation (RSD) of intra-day (RSD= 0.56– 0.91) and inter-day studies (RSD= 1.47). The mean recovery was found to be 100.01%. The acid and alkaline degradations of FFB in 1M HCl and 1M NaOH solutions showed an apparent zero-order kinetics with rate constants 0.0736 and 0.0698  min−1 respectively and the peroxide degradation with 5% H2O2 demonstrated an apparent first-order kinetics with rate constant k = 0.0202 per min. The t1/2, t90   values are also determined for all the kinetic studies. The developed method was found to be simple, specific, robust, linear, precise, and accurate for the determination of FFB in pharmaceutical formulations.  

Sign in / Sign up

Export Citation Format

Share Document