Tag Archives: HPLC

Comparative Enantioseparation of Amlodipine by HPLC and Capillary Electrophoresis

DOI: 10.2478/amma-2018-0001

Objective: The purpose of this study was to separate the enantiomers of amlodipine by High Performance Liquid Chromatography (HPLC) using ovomucoid (OVM) as chiral selector, respectively by Capillary Electrophoresis (CE) using cyclodextrines and to evaluate the analytical performance of the both proposed methods.
Material and methods: HPLC enantioseparation of amlodipine was performed on an HPLC Agilent Technologies 1100 series using as chiral stationary phase an Ultron ES OVM, 150×4.6 mm column with ovomucoid as chiral selector. The stereoselective CE analysis of amlodipine was achieved on Agilent Technologies 7100 CE using uncoated fused-silica capillaries 48 cm x 50 mm and different type of cyclodextrins as chiral selectors.
Results: A mobile phase consisting of 80% Na2HPO4 10 mM at a pH level of 5.0 and 20% ACN, isocratic elution at a flow of 1 ml/min turned to be the optimal experimental conditions for HPLC analysis (R=5.51; α=1.71) with retention times shorter than 10 minutes for the two isomers, tR (S-AML) = 4.63 (min); tR (R-AML) = 5.54 (min). The migration times for amlodipine enantiomers were tm (S-AML) = 8.15 (min) and tm (R-AML)= 8.45 (min) and the optimum CE conditions have proven to be a buffer solution containing 25 mM H3PO4 at pH 3.0 and 20 mM α-CD as chiral selector and a capillary temperature set at 15°C (R=1.51; α=1.03).
Conclusion: The analytical performances of the chromatographic method using OVM as chiral selector are superior to the electrophoretic analysis method but the CE method is more economical and may represent an alternative to the HPLC chromatographic separation.

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The Risk of Using Poppy Seed Tea Made from Several Varieties Available on the Romanian Market

DOI: 10.1515/amma-2017-0013

Objective: the number of alkaloids like morphine and codeine found in poppy seeds used in food industry are monitored by a directive given by European Food Safety Authority. Based on this regulation the aim of the study was to determine the quantity of morphine and codeine from several brands of poppy seeds.
Methods: an HPLC-UV method (205 nm) was developed to measure the quantity of morphine and codeine. Sample preparation was made using recipes posted on Drugs Forum by some users. Limits of detection were not determined because the lowest concentration from the reference (0.1 µg/ml) detected morphine concentrations that are far lower than a limit of toxicological concern.
Results: The concentrations, which were found, ranged between Below the Level of Toxicological Concern (BLTC) – 243.26 mg/kg for morphine and BLTC – 88.58 mg/kg for codeine using several methods of preparation.
Conclusions: one can observe that there are some brands of poppy seeds which do not respect the regulation about the amount of morphine and codeine. The high amount of morphine in some samples suggests that there are different varieties of poppy seeds, which can be used for an illicit purpose and can lead to addiction or even overdose in some cases.

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The Influence of Some Parameters on Chiral Separation of Ibuprofen by High-Performance Liquid Chromatography and Capillary Electrophoresis

DOI: 10.1515/amma-2017-0009

Objective: The aim of the study was to compare the influence of mobile phase composition and temperature on chiral separation of racemic ibuprofen by capillary electrophoresis and high performance liquid chromatography with UV detection.
Materials and methods: Racemic ibuprofen was analysed on a chiral OVM column with an HPLC system 1100 Agilent Technologies, under isocratic elution, by using potassium dihydrogen phosphate 20 mM and ethanol in mobile phase. The flow rate was set at 1 mL/min, UV detector at 220 nm and different column temperatures were tested. For electrophoresis separation an Agilent CE G1600AX Capillary Electrophoresis System system, with UV detection, was used. The electrophoresis analysis was performed at different pH values and temperatures, with phosphate buffer 25 mM and methyl-β-cyclodextrin as chiral selector.
Results: The chromatograhic analysis reveals a high influence of mobile phase pH on ibuprofen enantiomers separation. An elution with a mixture of potassium dihydrogen phosphate 20 mM pH=3 and ethanol, at 25ºC, allowed enantiomers separation with good resolution in less than 8 min.
Conclusions: The proposed HPLC method proved suitable for the separation of ibuprofen enantiomers with a good resolution, but the capillary electrophoresis tested parameters did not allow chiral discrimination.

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The Analysis of Flavonoids from Inula helenium L. Flowers and Leaves

Objective: In this study we investigated the flavonoids in the leaves and flowers of Inula helenium L..
Material and method: Flowers and leaves were harvested from the Medicinal Plant Garden of the University of Medicine and Pharmacy of Tîrgu Mureș. Dried vegetable product was extracted with methanol and in order to investigate aglycones we prepared hydrolised extracts. We screened the vegetable product for flavonoids using a TLC method, then we determined the total flavonoid content by a spectrophotometric method. HPLC-MS and HPLC-UV methods were used to determine polyphenols in methanolic and hydrolised extracts.
Results: Flavonoid content varies from 1.83% in leaves to 1.43% in flowers, equivalent in hyperoside. We identified the flavonols quercetin and kaempferol and the glycosides isoquercitrin, quercitrin and rutoside. Isoquercitrin is the major compound, in a concentration of 0.898 mg/g dry vegetable product.
Conclusions: Our study shows that the leaves and flowers of Inula helenium L. contain a high percentage of flavonoids with pharmacological activities.

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Presence of Nitrite and Nitrate Anions in Precipitation in Tîrgu Mureş and Surrounding Areas as a Result of Nitric Oxide Pollution

Objective: The city of Tîrgu Mureş, and of course other cities around the world, is polluted with nitrogen oxides. Most of the time, nitrogen oxides concentration into the air is between legal limits. However, this measurement is made on ground level and most of the pollutant gases are raised into the atmosphere from where is possible to return to the ground in form of nitrite and nitrate. These substances can contaminate soil and groundwater. The objective of the study was to measure nitrite and nitrate contents in groundwater and precipitation in and around Tîrgu Mureş.
Methods: A simple ion pair high pressure liquid chromatographic method with UV detection was used.
Results: High amounts of nitrite and nitrate were measured up to 25 km from the city of Tîrgu Mureş. An astonishing 4200 mg/ml melted snow was measured at about 100 m from the polluting plant. Other concentrations were between tens and hundreds of μg/ml melted snow. Rain water concentrations were in the same range. Most of the spring water samples we tested were over the drinking water limits stated by EU.
Conclusions: The high amounts of nitrites and nitrates found in precipitations around the city of Tîrgu Mureş show that pollution with nitrogen oxides goes beyond expected extent. This pollution is a health risk since precipitation will contaminate soil, and possibly crops will be contaminated too. Presence of airborne free radicals and activated pollutants will also increase due to the presence of these anions in unusual high amounts in air moisture.

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Simultaneous Determination of Atorvastatin and Amlodipine in Industrial Tablets by Apparent Content Curve and HPLC Methods

DOI: 10.2478/amma-2013-0010

Introduction: This study proposes the simultaneous determination of atorvastatin and amlodipine in industrial tablets by a quantitative spectrophotometric method, named the apparent content curve method, test method, and by an HPLC method with UV detection as reference method.
Materials and methods: A synthetic mixture and two fixed medicinal combinations containing amlodipine and atorvastatin were investigated by the apparent content curve method, a simple and relatively inexpensive UV-VIS spectrophotometric method based on a mathematical approach derived from the Lambert-Beer law. The results were compared with those obtained by an HPLC method.
Results: A good correlation of the results was obtained, the difference between the pair results was not significant (p >0.05).
Conclusions: The proposed spectrophotometric method is an easier and cheaper alternative for the quantitative determination of amlodipine and atorvastatin in industrial fixed-dose combinations.

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Analytical Performance of an HPLC and CZE Methods for the Analysis and Separation of Perindopril Erbumine and Indapamide

DOI: 10.1515/amma-2015-0073

Introduction: Perindopril, as an angiotensin converting enzyme inhibitor and indapamide, as a thiazide like diuretic, can be administrated together for the treatment of high blood preasure and other cardiovascular diseases. The aim of this study was to develop two simple and reliable separation methods for perindopril and indapamide by high performance liquid chromatography and capillary zone electrophoresis in order to evaluate their behaviour under separation conditions, for simultaneous separation.
Materials and methods: Standard solutions of perindopril erbumine and indapamide in proper solvents were analized. An Agilent 1100 series HPLC system was used for the separation of the two analytes on a C18 stationary phase (Zorbax Stable Bond 3.5 µm), under an isocratic elution. As a comparative method, an Agilent 7100 series capillary electrophoresis system was used for the development of the electrophoretic method.
Results: Both developed methods turned to comply to the separation performance parameters such as resolution and selectivity, with low limits of detection, wide range of liniarity. No statistical difference concerning precision of the qualitative parameters was observed. Time analysis less than 5 minutes both for chromatographic and electrophoretic separations proved to generate cost and time effective analysis methods.
Conclusions: Two analytical methods, HPLC and CZE respectively, for the separation of perindoprile erbumine and indapamide have been successfully developed, both recording satisfactory analytical parameters.

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Presence of Nitrate and Nitrite in Well Water in Mureș County

DOI: 10.1515/amma-2015-0063

Objective: One of the most important sources of nitrite and nitrate anions, besides vegetables and meat products, is the drinking water. Presence of nitrite and nitrate in the water in higher concentrations than those set by EFSA (0.5 mg/l nitrite, 50 mg/l nitrate), may have toxicological significance. A quantitative determination of these ions in samples collected from several pleases from Mureș County was made.
Methods: Ninety-seven well water samples were tested from 12 different places from Mureș County. We used a simple HPLC-UV ion pair method for the determination of nitrite and nitrate concentrations. Sensitivity of the method enables the quantification for concentrations far below the MCL value.
Results: The highest amounts of nitrate and nitrite were measured in Sângeorgiu de Mureș and Cristeșt. Concentrations of nitrite and nitrate were exceeded in 4.12% and respectively 44.32% of the samples.
Conclusions: The high amounts of nitrites and nitrates existing in well water go beyond the expected extent. This pollution can become a health risk since this water is used in human nutrition especially in child nourishment.

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