Chemometric Approach to Evaluate the Parameters Affecting Electrospray: Application of a Statistical Design of Experiments for the Study of Arginine Ionization

2005 ◽  
Vol 11 (4) ◽  
pp. 361-370 ◽  
Author(s):  
Laurence Charles ◽  
Stéphanie Caloprisco ◽  
Salimo Mohameda ◽  
Michelle Sergent
Keyword(s):  
Formic Acid ◽  
Acid Concentration ◽  
Flow Rate ◽  
Mobile Phase ◽  
Gas Flow ◽  
Statistical Design ◽  
Statistical Design Of Experiments ◽  
Experimental Conditions ◽  
Mobile Phase Flow Rate ◽  
Methanol Content

The effects of different experimental parameters on arginine electrospray ionization have been investigated with response surface modeling design. This chemometric technique allows a study of the effects of selected experimental variables and their interactions on the response of an experiment by performing a limited number of analyses. Six variables were studied: methanol content in the liquid phase, formic acid concentration, electrospray voltage, orifice voltage, mobile phase flow rate, and sheath gas flow rate. Signal abundance and signal-to-noise ratio of the protonated molecule and the protonated dimer were measured from the electrospray mass spectra and these four responses were tested by the design. The factor that exhibits the greatest influence on MH+ abundance is shown to be the liquid flow rate whereas the formation of protonated dimers is mainly controlled by the percentage of methanol in the mobile phase. A strong synergic effect of methanol content and formic acid concentration in the liquid has also been demonstrated in the study of noise level. Moreover, the capabilities of the multicriteria optimization method have been demonstrated through the successful prediction of a set of optimal experimental conditions.

SIMULTANEOUS ESTIMATION OF CURCUMIN AND GEFITINIB IN BULK AND TISSUE SAMPLES (PLASMA AND BRAIN HOMOGENATE) BY RP-HPLC: APPLICATION TO A DISTRIBUTION STUDY

INDIAN DRUGS ◽  
2019 ◽  
Vol 56 (07) ◽  
pp. 59-68
Author(s):  
H Mahajan ◽  
S Savale ◽  
P Nerkar ◽  
Keyword(s):  
Flow Rate ◽  
Mobile Phase ◽  
Internal Standard ◽  
Brain Homogenate ◽  
Reversed Phase ◽  
Hplc Method ◽  
Simultaneous Estimation ◽  
Bulk Analysis ◽  
Experimental Conditions ◽  
Rp Hplc

The present study was aimed at developing a Reversed-Phase High-Performance Liquid Chromatography (RP-HPLC) method for simultaneous determination of curcumin (CRM) and gefitinib (GFT) in bulk, plasma and brain homogenate. hydrochlorothiazide was used as an internal standard (IS). A new simple, rapid, selective, precise and accurate RP-HPLC method has been developed. The separation was achieved by using C-18 column (Qualisil BDS C18, 250 mm x 4.6 mm I.D.) coupled with a guard column of silica, mobile phase consisted of acetonitrile: water with 0.1% formic acid (30:70 v/v). The flow rate was 0.2 ml/min and the drug was detected using PDA detector at the wavelength of 242 nm. The experimental conditions, including the diluting solvent, mobile phase composition, column saturation and flow rate, were optimised to provide high-resolution and reproducible peaks. The method was developed and tested for linearity range of 10-60 μg/mL for bulk analysis and 200-800 ng/mL for plasma and brain homogenate. The developed method was validated as per ICH guidelines, in terms of linearity, application of the proposed method to bulk sample, recovery, precision, repeatability, ruggedness, sensitivity (LOD and LOQ) and robustness and stability study (short and long-term stabilities, freeze/thaw stability, post-preparative). The low value of % RSD showed that the method was precise within the acceptance limit of 2%. The developed method was successfully applied for the analysis of the drug in bulk as well as various marketed formulation and drug in plasma and brain distribution studies.

scholarly journals Purification of Flavonoids from Mulberry Leaves via High-Speed Counter-Current Chromatography

Processes ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 91 ◽  
Author(s):  
Pian Zhang ◽  
Kang-Ling Zhu ◽  
Jun Zhang ◽  
Yan Li ◽  
Heng Zhang ◽  
...  
Keyword(s):  
Flow Rate ◽  
Mobile Phase ◽  
High Speed ◽  
Separation Efficiency ◽  
Phase Flow ◽  
Mobile Phase Flow Rate ◽  
Mulberry Leaves ◽  
Mulberry Leaf ◽  
Solvent Systems ◽  
Counter Current

In order to obtain high-purity flavonoid products, the extracts from mulberry leaves were separated and purified via high-speed counter-current chromatography (HSCCC). Moreover, the product was detected via high-performance liquid chromatography (HPLC). The characteristic absorption wavelength of the rutin standard for HSCCC detection and HPLC analysis at 257 nm was tested by ultraviolet scanning analysis. The effect of solvent systems and mobile phase flow rate on the separation efficiency were then researched. Finally, the solvent system of V(ethyl acetate):V(n-butanol):V(water) = 4:1:5 was selected as the operating system for HSCCC. This work theoretically analyzed the impact of the molecular structure and polarity of flavonoids on the choice of solvent systems. The results showed that the mobile phase flow rate had a great influence on the separation efficiency. Furthermore, the separation efficiency increased as the mobile phase flow rate decreased. When the mobile phase flow rate was 5 mL/min, the peak time for flavonoids was 140 min, the retention of the stationary phase was 56.4%, and the purity of the product reached 93.8%. The results of this study greatly improved the purity of flavonoids in mulberry leaf and provided a strong support for the separation and purification of mulberry leaf extract.

scholarly journals Flow-dependent separation selectivity for organic molecules on metal–organic frameworks containing adsorbents

2016 ◽  
Vol 52 (30) ◽  
pp. 5301-5304 ◽  
Author(s):  
Anton Peristyy ◽  
Pavel N. Nesterenko ◽  
Anita Das ◽  
Deanna M. D'Alessandro ◽  
Emily F. Hilder ◽  
...  
Keyword(s):  
Flow Rate ◽  
Mobile Phase ◽  
Organic Molecules ◽  
Metal Organic Frameworks ◽  
Phase Flow ◽  
Mobile Phase Flow Rate ◽  
Separation Selectivity ◽  
Metal Organic

A new effect was discovered which allows changes of selectivity by variation of the mobile phase flow rate.

scholarly journals Development and validation of a rapid selective high-throughput LC-MS/MS method for the determination of triclabendazole sulfoxide concentrations in sheep plasma and its use in bioequivalence studies

2021 ◽  
Author(s):  
Lénárd Farczádi ◽  
Álmos Dósa ◽  
Orsolya Melles ◽  
Laurian Vlase
Keyword(s):  
Formic Acid ◽  
Flow Rate ◽  
Mobile Phase ◽  
Liver Fluke ◽  
Internal Standard ◽  
Gradient Elution ◽  
Sample Processing ◽  
Development And Validation ◽  
Analytical Separation

AbstractTriclabendazole is one of the main drugs used to treat liver fluke in livestock. A rapid LC-MS/MS method was developed and validated to determine ovine plasma levels of triclabendazole sulfoxide.A Gemini NX-C18 column was used to achieve analytical separation, with gradient elution of a mobile phase composed of 0.1% formic acid in acetonitril and 0.1% formic acid in water at flow rate of 0.6 mL/min. MRM with positive ESI ionization was used for the detection of triclabendazole sulfoxide (m/z 360.10 from m/z 376.97). Fenbendazole was used as internal standard. Plasma protein precipitation with acetonitrile was used for sample processing.The method was validated with regards to selectivity, linearity (r > 0.9939), within run and between run precision (CV < 8.9%) and accuracy (bias < 8.9%) over the concentration range 1–100 µg/mL plasma.The method developed is simple, selective and can be applied in bioequivalence and bioavailability studies.

scholarly journals Development and Validation of LC Method for the Determination of Famciclovir in Pharmaceutical Formulation Using an Experimental Design

2008 ◽  
Vol 5 (1) ◽  
pp. 58-67 ◽  
Author(s):  
Srinivas Vishnumulaka ◽  
Narasimha Rao Medicherla ◽  
Allam Appa Rao ◽  
G. Edela Srinubabu
Keyword(s):  
Experimental Design ◽  
Flow Rate ◽  
Mobile Phase ◽  
Internal Standard ◽  
Pharmaceutical Formulations ◽  
Hplc Method ◽  
Internal Standard Method ◽  
Intermediate Precision ◽  
Mobile Phase Flow Rate ◽  
Development And Validation

A rapid and sensitive RP-HPLC method with UV detection (242 nm) for routine analysis of famciclovir in pharmaceutical formulations was developed. Chromatography was performed with mobile phase containing a mixture of methanol and phosphate buffer (50:50,v/v) with flow rate 1.0 mL min−1. Quantitation was accomplished with internal standard method. The procedure was validated for linearity (correlation coefficient =0.9999), accuracy, robustness and intermediate precision. Experimental design was used for validation of robustness and intermediate precision. To test robustness, three factors were considered; percentage v/v of methanol in mobile phase, flow rate and pH; flow rate, the percentage of organic modifier and pH have considerable important effect on the response. For intermediate precision measure the variables considered were: analyst, equipment and number of days. The RSD value (0.86%,n=24) indicated an acceptable precision of the analytical method. The proposed method was simple, sensitive, precise, accurate and quick and useful for routine quality control.

Limitations of Statistical Design of Experiments Approaches in Engineering Testing

2000 ◽  
Vol 122 (2) ◽  
pp. 254-259 ◽  
Author(s):  
Stelu Deaconu ◽  
Hugh W. Coleman
Keyword(s):  
Experimental Data ◽  
Design Of Experiments ◽  
Regression Models ◽  
Statistical Design ◽  
Statistical Design Of Experiments ◽  
Experimental Conditions ◽  
True Value ◽  
Correct Model ◽  
Degree Of Confidence ◽  
Significant Change

A hypothetical experiment and Monte Carlo simulations were used to examine the effectiveness of statistical design of experiments methods in identifying from the experimental data the correct terms in postulated regression models for a variety of experimental conditions. Two analysis of variance techniques (components of variance and pooled mean square error) combined with F-test statistics were investigated with first-order and second-order regression models. It was concluded that there are experimental conditions for which one or the other of the procedures results in model identification with high confidence, but there are also other conditions in which neither procedure is successful. The ability of the statistical approaches to identify the correct models varies so drastically, depending on experimental conditions, that it seems unlikely that arbitrarily choosing a method and applying it will lead to identification of the effects that are significant with a reasonable degree of confidence. It is concluded that before designing and conducting an experiment, one should use simulations of the proposed experiment with postulated truths in order to determine which statistical design of experiments approach, if any, will identify the correct model from the experimental data with an acceptable degree of confidence. In addition, no significant change in the effectiveness of the methods in identifying the correct model was observed when systematic uncertainties of up to 10 percent in the independent variables and in the response were introduced into the simulations. An explanation is that the systematic errors in the simulation data caused a shift of the whole response surface up or down from the true value, without a significant change in shape. [S0098-2202(00)03102-3]

Gas chromatography with programming the mobile phase flow rate

1979 ◽  
Vol 12 (5) ◽  
pp. 271-276 ◽  
Author(s):  
S. A. Volkov ◽  
Yu. A. Sultanovich ◽  
K. I. Sakodinskii
Keyword(s):  
Gas Chromatography ◽  
Flow Rate ◽  
Mobile Phase ◽  
Phase Flow ◽  
Mobile Phase Flow Rate

scholarly journals RP-HPLC Method Development and Validation for the Estimation of Lansoprazole in Presence of Related Substances by QbD Approach

2021 ◽  
pp. 138-150
Author(s):  
Sachin B. Gholve ◽  
Jaiprakash N. Sangshetti ◽  
Omprakash G. Bhusnure ◽  
Ram S. Sakhare ◽  
Pratap H. Bhosale ◽  
...  
Keyword(s):  
Flow Rate ◽  
Mobile Phase ◽  
Method Development ◽  
Hplc Method ◽  
Drug Substance ◽  
Gastric Ulcers ◽  
Mobile Phase Flow Rate ◽  
Column Temperature ◽  
Rp Hplc

A rapid specific RP-HPLC method has been developed for the determination of Lansoprazole impurities in the drug substance. The control of pharmaceutical impurities is currently a critical issue in the pharmaceutical industry. The International Council for Harmonization (ICH) has formulated a workable guideline regarding the control of impurities. The objective of the recent study was to develop and validate a HPLC method for the quantitative determination of process-related impurities of Lansoprazole in pharmaceutical drug substance. Lansoprazole, 2-[[[3-methyl-4-(2,2,2-trifluoroethoxy)-2-pyridinyl] methyl]-sulfinyl]- 1H-benzimidazole is an proton pump inhibitor used in the management of gastric ulcers. Chromatographic identification of the impurities was carried out by response surface methodology, applying a three-level Box Behnken design with three center points. Three factors selected were a mobile phase, flow rate, column temperature. Evaluation of the main factor, their interaction, and the quadric effect on peak resolution were done on Waters Symmetry C8, 250 x 4.6mm, 5µm column is used for the development of the method. The mobile phase consists of buffer and acetonitrile. The flow rate of the mobile phase was 1.0 ml/min with gradient elution. The column temperature is ambient and the detection wavelength is 235 nm. The injection volume was 10 µL. The method was validated as per ICH guidelines for linearity in the range of 50-150 µg/ml and the LOD & LOQ values obtained were 0.437×10-4 and 0.1325×10-3 µg/ml respectively which specifies the method's sensitivity. The proposed method was successfully used to determine the Lansoprazole impurities in drug substances.

scholarly journals Development and Validation of an HPLC Method for the Determination of the macrolide antibiotic Clarithromycin using Evaporative Light Scattering Detector in raw materials and Pharmaceutical Formulations

2017 ◽  
Vol 6 (4) ◽  
pp. 133-141 ◽  
Author(s):  
Zampia Tzouganaki ◽  
Michael Koupparis
Keyword(s):  
Flow Rate ◽  
Mobile Phase ◽  
Gas Flow ◽  
Raw Materials ◽  
Pharmaceutical Formulations ◽  
Reversed Phase ◽  
Hplc Method ◽  
Ich Guidelines ◽  
Development And Validation

In this work, ELS-Detector has been used for the development of an HPLC method for the determination of clarithromycin in pharmaceutical formulations (tablets and pediatric suspension). Isocratic reversed phase HPLC approach has been developed using a C-18 column (Waters Spherisorb 5 μm ODS2, 4.6x250 mm) and a mobile phase consisting of acetonitrile / aqueous trifluoroacetic acid as pairing reagent. Experimental parameters (temperature of heated drift tube, flow rate of mobile phase, gas flow rate, mobile phase composition) were optimized. Clarithromycin’ s stability was thoroughly examined in different solvent systems. Using the optimized conditions the working range was 5-100 μg/mL (upper limit can be increased considerably), with a detection limit of 4.5 μg/mL (6x10-6 M). The method was validated as per ICH guidelines. The retention time was 4.7 min. The method was successfully applied for the content assay of clarithromycin formulations.

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