scholarly journals Gradient HPLC in the determination of drug lipophilicity and acidity

2001 ◽  
Vol 73 (9) ◽  
pp. 1465-1475 ◽  
Author(s):  
Roman Kaliszan ◽  
Piotr Haber ◽  
Tomasz Baczek ◽  
Danuta Siluk
Keyword(s):  
Mobile Phase ◽  
High Performance ◽  
Standard Procedure ◽  
Gradient Elution ◽  
Log P ◽  
Retention Data ◽  
Organic Modifier ◽  
Wide Range ◽  
Aqueous Component ◽  
Initial Ph

The linear-solvent strength (LSS) model of gradient elution in high-performance liquid chromatography (HPLC) has been demonstrated to provide parameters of lipophilicity and acidity of analytes. pKa and log kw values are determined in three gradient runs. The first two experiments use an aqueous buffered eluent with a wide-range organic modifier gradient at pH of buffer, providing suppression of ionization of the analyte. That experiment allows an estimate of contents of the organic modifier in the mobile phase (%B), producing requested retention coefficient, k, for the nonionized form of the analyte. The next experiment is carried out with the latter %B and a pH-gradient of the aqueous component of the eluent that is sufficient to overlap possible pKa value of the analyte. The initial pH of the buffer used to make the mobile phase is selected to insure that the analyte is in nonionized form. The resulting retention time allows an estimate of pKa in a solvent of the given %B.The log kw parameter obtained correlated well with the corresponding value obtained by the standard procedure of extrapolation of retention data determined in a series of isocratic measurements. The correlation between log kw and the reference parameter of lipophilicity, log P, was very good for a series of test analytes. The values of pKa were found to correlate with the literature pKa data determined in water for a set of aniline derivatives studied.

scholarly journals Preparation and Hydro-Lipophilic Properties of Methoxylated and Methylated 1-Hydroxynaphthalene-2-Carboxanilides

Proceedings ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 43 ◽  
Author(s):  
Iva Kapustikova ◽  
Tomas Gonec ◽  
Jiri Kos ◽  
Ewelina Spaczynska ◽  
Michal Oravec ◽  
...  
Keyword(s):  
Mobile Phase ◽  
High Performance ◽  
Chemical Structure ◽  
Reversed Phase ◽  
Log P ◽  
Organic Modifier ◽  
Chromatography Method ◽  
P Values ◽  
Liquid Chromatography Method ◽  
Substituted 1

A series of variously methoxylated and methylated N-aryl-1-hydroxynaphthalene-2-carboxanilides was prepared and characterized as potential anti-invasive agents. As it is known that lipophilicity significantly influences the biological activity of compounds, the hydro-lipophilic properties of these mono-, di- and tri-substituted 1-hydroxynaphthalene-2-carboxanilides are investigated in the study. All the discussed hydroxynaphthalene derivatives were analyzed using the reversed-phase, high-performance liquid chromatography method, to measure lipophilicity. The procedure was performed under isocratic conditions with methanol as an organic modifier in the mobile phase, using an end-capped, non-polar C18 stationary reversed-phase column. The present study discusses the correlations between the logarithm of the capacity factor k and log P/Clog P values, calculated in various ways, as well as the relationships between the lipophilicity and the chemical structure of the studied compounds.

Analysis of organic impurities of besifloxacin hydrochloride by high performance liquid chromatography with isocratic and gradient elution.

2019 ◽  
Vol 16 ◽  
Author(s):  
Joanna Wittckind Manoel ◽  
Camila Ferrazza Alves Giordani ◽  
Livia Maronesi Bueno ◽  
Sarah Chagas Campanharo ◽  
Elfrides Eva Sherman Schapoval ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Mobile Phase ◽  
High Performance ◽  
Gradient Elution ◽  
Pharmaceutical Product ◽  
Raw Material ◽  
Isocratic Elution ◽  
Organic Impurities ◽  
Elution Method

Introduction: Impurity analysis is an important step in the quality control of pharmaceutical ingredients and final product. Impurities can arise from drug synthesis or excipients and even at small concentrations may affect product efficacy and safety. In this work two methods using high performance liquid chromatography (HPLC) were developed and validated for the evaluation of besifloxacin and its impurity synthesis, with isocratic elution and another with gradient elution. Method: The analysis by HPLC in isocratic elution mode was performed using a cyano column maintained at 25 °C. The mobile phase was composed by 0.5% triethylamine (pH 3.0): acetonitrile (88:12 v/v) eluted at a flow rate of 1.0 ml/min with detection at 330 nm. The gradient elution method was carried out with the same column and mobile phase components only modifying the rate between organic and aqueous phase during analysis. The procedures have been validated according to internationally accepted guidelines, observing results within acceptable limits. Results: The methods presented were found to be linear in the 140 to 260 µg/ml range for besifloxacin and 0.3 to 2.3 µg/ml for an impurity named A. The limits of detection and quantification were respectively 0.07 and 0.3 µg/ml for impurity A, with a 20 µL injection volume. The precision achieved for all analyses performed provided RSD inter-day equal to 6.47 and 6.36% for impurity A with isocratic elution and gradient, respectively. The accuracy was higher than 99% and robustness exhibited satisfactory results. In the isocratic method an analysis time of 25 min and 15 min was obtained for gradient. For impurity A, the number of theoretical plates in the isocratic mode was about 5000 while in the gradient mode it was about 45000, hence, it made the column more efficient by changing the mobile phase composition during elution. In besifloxacin raw material and in pharmaceutical product used in this study, other related impurities were present but but impurity A was searched for and not detected Conclusion: The proposed methods can be applied for quantitative determination of impurities in the analysis of the besifloxacin raw material, as well as in ophthalmic suspension of the drug, considering the quantitation limit.

scholarly journals Preparation and Hydro-Lipophilic Properties of Selected Novel Chlorinated and Brominated N-Arylcinnamamides

Proceedings ◽  
2019 ◽  
Vol 41 (1) ◽  
pp. 11
Author(s):  
Tomas Strharsky ◽  
Timotej Jankech ◽  
Jiri Kos ◽  
Kristina Maricakova ◽  
Andrea Pramukova ◽  
...  
Keyword(s):  
High Performance ◽  
Chemical Structure ◽  
Antimicrobial Agents ◽  
Reversed Phase ◽  
Log P ◽  
Organic Modifier ◽  
Chromatography Method ◽  
P Values ◽  
Liquid Chromatography Method ◽  
Derivatives Of

A series of six di- and tri-halogenated N-arylcinnamanilides designed as anti-inflammatory and antimicrobial agents was prepared and characterized. Since it is known that lipophilicity significantly influences the biological activity of compounds, the hydro-lipophilic properties of these di- and tri-substituted N-arylcinnamanilides were investigated in the study. All the discussed derivatives of cinnamic acid were analyzed using the reversed-phase high performance liquid chromatography method to measure lipophilicity. The procedure was performed under isocratic conditions with methanol as an organic modifier in the mobile phase using an end-capped non-polar C18 stationary reversed-phase column. In the present study, the correlations between the logarithm of the capacity factor k and log P/Clog P values calculated in various ways as well as the relationships between the lipophilicity and the chemical structure of the studied compounds are discussed.

Detection of Synthetic Drugs as Adulterants in Natural and Herbal Slimming Products by LC-ESI-MS/MS with Polarity Switching

2016 ◽  
Vol 99 (4) ◽  
pp. 929-940 ◽  
Author(s):  
Phyllis Wilson ◽  
Claude Masse
Keyword(s):  
Weight Loss ◽  
Simultaneous Detection ◽  
Gradient Elution ◽  
Ammonium Formate ◽  
Synthetic Drugs ◽  
Polarity Switching ◽  
Validation Parameters ◽  
Wide Range ◽  
Aqueous Component ◽  
Positive Mode

Abstract The purpose of this study was to develop an LC-tandem MS method for the simultaneous detection of common synthetic drugs as adulterants in natural and herbal slimming products. Sixteen drugs belonging to a wide range of pharmaceutical classes were studied. Included in the list of drugs were anorexics, anxiolytics, antidepressants, diuretics, laxatives, and stimulants. The method used a C18 column (4.6 × 50 mm and 1.8 μm particle size). Separation of the drugs was achieved by gradient elution using 4 mM ammonium formate in water + 0.1% formic acid as the aqueous component and 4 mM ammonium formate in methanol + 0.1% formic as the organic component of the mobile phase. As not all of the analytes ionized in the positive mode, the mass spectrometer was operated in the electrospray ionization mode with polarity switching. The samples were extracted with methanol and the use of 50% acetonitrile in water and 50% methanol in water were investigated as diluents for injection into the LC-MS system. Utilizing both diluents, the validation parameters including accuracy, precision, LOD, and LOQ were assessed. The validation results and utilization of the method to analyze a variety of weight-loss supplements indicate that the two diluents give similar results and can be used interchangeably. This knowledge provides the user with the option of selecting either diluent for sample preparation depending on the sample matrix without having to revalidate the method. The method was applied to the analysis of weight-loss supplements available in local pharmacies, herbal pharmacies, and over the Internet.

scholarly journals Method Development and Validation for Quantification of Potential Genotoxic Impurity, PyCl in Lansoprazole Hydrochloride using Liquid Chromatography Combined with Mass Spectrometry

2021 ◽  
Vol 33 (5) ◽  
pp. 1165-1168
Author(s):  
C. Purushotham Reddy ◽  
G. Venkateswara Rao ◽  
K. Ramakrishna ◽  
K.M.V. Narayana Rao
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Mobile Phase ◽  
High Performance ◽  
Method Development ◽  
Limit Of Detection ◽  
Gradient Elution ◽  
Solution Stability ◽  
Selective Ion Monitoring ◽  
Acquity Uplc

A sensitive and robust high performance liquid chromatography combined with tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of potential genotoxic impurity (PGI), 2-(chloromethyl)-3-methyl-4-(2,2,2-trifluoroethoxy)-pyridine hydrochloride (PyCl) in lansoprazole as per ICH Q2 guideline. In this method, PyCl and lansoprazole were well-separated from each other on Acquity UPLC BEH-C18 column (50 × 4.6 mm × 1.7 μ) in a gradient elution mode with the mobile phase consisting of 0.1% formic acid in water (mobile phase-A) and acetonitrile (mobile phase-B) at a flow rate of 0.4 mL/min. For the quantitation of Py-Cl, selective ion monitoring (SIM) mode was used with m/z 240 ion in LC-MS method. The validated method was found to be precise, accurate and linear from the range of LOQ level to 150% with respect to sample concentration and the correlation co-efficient was found to be 0.998. Limit of detection (LOD) and limit of quantifications (LOQ) were found to be 0.000012 and 0.000004 mg/mL, respectively. The validated method was found to be sensitive and the recoveries were found to be well within the range from 83.4% to 95.9% for Py-Cl. Further, the solution stability was also established as the same were found to be stable upto 24 h.

scholarly journals Simultaneous Identification and Quantification of Three Xanthones and Two Polyisoprenylated Benzophenones in Eight Indian Garcinia Species Using a Validated UHPLC-PDA Method

2019 ◽  
Vol 102 (5) ◽  
pp. 1423-1434
Author(s):  
Azazahemad A Kureshi ◽  
Chirag Dholakiya ◽  
Tabaruk Hussain ◽  
Amit Mirgal ◽  
Siddhesh P Salvi ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Mobile Phase ◽  
Plant Secondary Metabolites ◽  
Gradient Elution ◽  
Garcinia Cambogia ◽  
Wide Range ◽  
Photodiode Array ◽  
Simultaneous Identification ◽  
Gradient Elution Mode ◽  
Identification And Quantification

Abstract Background: Xanthones and polyisoprenylated benzophenones (PIBs) are two important classes of plant secondary metabolites with a wide range of bioactivities. Garcinia species synthesize numerous xanthones and PIBs. As per the literature, no data claiming simultaneous identification and quantification of three xanthones, α-mangostin, β-mangostin, γ-mangostin, and two PIBs, xanthochymol, isoxanthochymol, were found. Methods: A validated ultra-HPLC (UHPLC)-photodiode array (PDA) method for the simultaneous identification and quantification of five compounds in different extracts of eight Indian Garcinia species was developed. The compounds were separated on a Waters ACQUITY™ UPLC H-Class column using a mobile phase consisting of solvents 0.1% formic acid in water (A) and methanol (B) in gradient elution mode. The total run time was 9 min. Results: From fruit rinds of eight Indian Garcinia species, namely Garcinia cambogia, G. cowa, G. indica, G. loniceroides, G. mangostana, G. morella, G. pedunculata, and G. xanthochymus, extracts were prepared using solvents of varying polarity. These extracts were analyzed for five biologically important compounds, namely α-mangostin, β-mangostin, γ-mangostin, xanthochymol, and isoxanthochymol. The results revealed that there is a wide variation in concentration of these compounds in extracts of Garcinia species. Conclusions: The developed and validated UHPLC-PDA method could be used for simultaneous identification and quantification of these five compounds for bioprospection of other Garcinia species.

Separation of metal-cyanide complexes by reversed-phase ion-interaction high-performance liquid chromatography

1994 ◽  
Vol 72 (2) ◽  
pp. 269-273 ◽  
Author(s):  
Louis Giroux ◽  
Dwight J. Barkley
Keyword(s):  
Ionic Strength ◽  
Mobile Phase ◽  
High Performance ◽  
Reversed Phase ◽  
Organic Modifier ◽  
Experimental Conditions ◽  
Metal Cyanide ◽  
Cyanide Complexes ◽  
Cyano Complexes ◽  
Phase Differences

Reversed-phase ion-interaction chromatography has been used to study the separation of Cu(I), Ag(I), Ni(II), Au(I), Co(III), Fe(III), and Fe(II) cyano complexes on silica and carbon-based reversed-phases with UV detection at 215 nm. Separation of the metal-cyanide complexes was affected by a number of experimental factors including the nature and concentration of the organic modifier, nature and concentration of the ion-pairing reagent, pH, and ionic strength of the mobile phase. Differences between the elution order of metallo-cyanides observed in the present work and in other investigations under similar experimental conditions are explained by a difference in the ionic strength of the mobile phase. Finally, this technique is used to analyze metal-cyanide complexes in a gold mill solution.

scholarly journals A Simple Analytical Method for High-Throughput Screening of Major Sugars from Soybean by Normal-Phase HPLC with Evaporative Light Scattering Detection

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Babu Valliyodan ◽  
Haiying Shi ◽  
Henry T. Nguyen
Keyword(s):  
Light Scattering ◽  
Analytical Method ◽  
High Throughput Screening ◽  
Mobile Phase ◽  
High Performance ◽  
Pure Water ◽  
Gradient Elution ◽  
Chromatographic Retention ◽  
Simple Analytical Method ◽  
Evaporative Light Scattering

This paper presents a simple analytical method for determining sugars in soybean (Glycine max (L.) Merr.) tissues. Sample preparation was modified from several early published methods. High-performance liquid chromatography (HPLC) equipped with an evaporative light scattering detector (ELSD) was used to separate, identify, and quantify seven sugars, including glucose, galactose, fructose, sucrose, melibiose, raffinose, and stachyose. Two mobile phases were programed into a gradient elution. Mobile phase A is pure water and mobile phase B is a mixture of acetonitrile and acetone 75 : 25 (v/v). Total chromatographic retention time is less than 20 minutes. This method has been validated for detection limit, calibration range, and intraday and interday repeatability. This method has been used analyzing more than 5000 soybean samples in the experiments studying natural genetic variation of sugar contents and components in soybean seeds and other tissues.

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