bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of a Method to Determine Flavonol Aglycones in Ginkgo biloba Dietary Supplement Crude Materials and Finished Products by High-Performance Liquid Chromatography: Collaborative Study
Authors: Gray Dean , LeVanseler Kerri , Pan Meide , Waysek Edward H , Chandra A 
Published: February 2020

Abstract
An interlaboratory study was conducted for evaluation of a method to determine the flavonol aglycones quercetin, kaempferol, and isorhamnetin in Ginkgo biloba products. The method calculates total glycosides based on these aglycones formed after acid hydrolysis. Twelve matrixes were chosen for study by 12 collaborating laboratories in 2 countries. Test materials included crude leaf material, standardized dry powder extract, single and multiple entity finished products, ethanol and glycerol tinctures, and National Institute of Standards and Technology (NIST) standard reference materials (SRMs). Results from 11 laboratories were used for the final calculations. Eight of the 12 matrixes evaluated produced acceptable results for total flavonol glycosides, with HorRat scores ranging from 1.31 to 2.05; repeatability relative standard deviations (RSDr) from 1.46 to 4.14; and reproducibility relative standard deviations (RSDR) from 4.67 to 9.69. These 8 matrixes consisted primarily of simple dosage forms (e.g., dry powder extracts, crude leaf samples, liquid extracts, and SRMs) and a single tablet product (Ginkgo Awareness). Four additional matrixes, consisting of 3 tablets and 1 soft gel product (Ginkgold, Ginkoba, Ginkogen, and Ginkgo Phytosome, respectively), showed greater total flavonol glycoside HorRat scores in comparison, ranging from 2.39 to 5.13, with RSDr values from 2.83 to 8.16, and RSDR values from 8.53 to 20.4. Based on the results presented here, the method is recommended for Official First Action for determination of total flavonol glycosides calculated from quercetin, kaempferol, and isorhamnetin in dry powder extracts, crude leaf material, liquid extracts, and a select finished product, Ginkgo Awareness.
Direct Injection Liquid Chromatographic Technique for Simultaneous Determination of Two Antihistaminic Drugs and Their Main Metabolites in Serum
Authors: Emara Samy , El-Gindy Alaa , Mesbah Mostafa K , Hadad Ghada M 
Published: February 2020

Abstract
A very simple liquid chromatographic technique was developed and validated for the simultaneous determination of 2 antihistaminic drugs, loratadine (LT) and terfenadine (TR), and their major active metabolites, desloratadine (DL) and fexofenadine (FX), respectively, in human serum. LT, DL, TR, and FX from directly injected serum samples were enriched on a protein-coated RP8 silica precolumn (10 4.6 mm id) while serum constituents, such as proteins and salts, were eluted to waste. Using an online column-switching system, the drugs and their metabolites were quantitatively transferred and separated on a second analytical column (Shim-pack 5 μm particle size cyanopropyl, 250 × 4.6 mm id) followed by ultraviolet detection at 243 nm for LT and DL and 220 nm for TR and FX. Very good precision, accuracy, and linearity were obtained over the range of 101000 ng/mL for LT and DL, 10500 ng/mL for TR, and 103000 ng/mL for FX in human serum. High extraction recoveries from serum ranging from 96.03 to 98.19, 95.44 to 97.26, 95.61 to 98.17, and 95.60 to 97.89 for LT, DL, TR, and FX, respectively, were obtained.
Evaluating the Use of Fatty Acid Profiles to Identify Francisella tularensis
Authors: Whittaker Paul , Day James B , Curtis Sherill K , Fry Frederick S 
Published: February 2020

Abstract
Rapid capillary gas chromatography (GC) with flame-ionization detection was used to determine the cellular fatty acid profiles of Francisella tularensis. Two subspecies of F. tularensis, the live vaccine strain (LVS) derived from holarctica and a novicida strain Utah 112 (U112), were used to compare the extracted fatty acid methyl esters (FAMEs). A data set for the 2 subspecies was prepared using fatty acid profiles of bacteria grown on 2 types of media, Mueller-Hinton and cysteine heart agar supplemented with 5% rabbit blood (CHAB), and harvested at various time intervals (Day 1 through Day 4) with replicates prepared on different days. A total of 204 samples were analyzed. The results showed that these fatty acid quantitative profiles were unique for each of the subspecies and could be used as a fingerprint for the organism. It was determined by this rapid method that approximately 88% of the fatty acids in both the LVS and U112 strains included 6 saturated fatty acids: 10:0, 12:0, 14:0, 16:0, 18:0, and 20:0; and 4 hydroxy fatty acids 10:0 2OH, 16:0 3OH, 17:0 3OH, and 18:0 3OH. Data analysis and determination of clustering were performed by principal component analysis (PCA) and soft independent modeling of class analogy (SIMCA). Both PCA and SIMCA showed clear separation of the LVS and U112 strain and would be useful for prediction of unknowns. It was determined that the incubation time can be reduced from 48 to 24 h, and results are highly predictive for the identification of F. tularensis. In summary, analysis of FAMEs from F. tularensis subspecies LVS and U112 grown on CHAB or Mueller-Hinton media, and using a rapid GC method can provide a sensitive procedure for identification of these organisms.
Determination of Mammalian Lignans in Biological Samples by Modified Gas Chromatography/Mass Spectrometry
Authors: Bommareddy Ajay , Arasada Bhanu L , Mathees Duane P , Dwivedi Chandradhar 
Published: February 2020

Abstract
Lignans in flaxseed have been part of the human diet for centuries. In 1955, the isolation and structure of the lignan derivative secoisolariciresinol diglucoside (SDG) was reported. The biological role of SDG and mammalian lignan metabolites enterodiol and enterolactone was initially reported 20 years later. Experimental evidences showed the beneficial effects of lignans on breast, colon, and thyroid cancer. A modified gas chromatography/mass spectrometry (GC/MS) assay was developed for lignans in serum and colon samples of rats fed flaxseed meal. The method developed for the analysis of metabolites involves extraction and derivatization of samples and quantitative analysis by selected ion monitoring using GC/MS. The levels of lignan metabolites enterodiol and enterolactone were determined to be 0.013 and 0.23 M in serum samples and 0.008 and 1.63 M in colon samples.
Application of a Validated Method in the Stability Study of Colistin Sulfate and Methylparaben in a Veterinary Suspension Formulation by High-Performance Liquid Chromatography with a Diode Array Detector
Authors: PÉrez-Lozano Pilar , GarcÍa-Montoya Encarna , Orriols Anna , MiÑarro Montse , TicÓ Josep Ramon , SuÑÉ-Negre Josep Maria 
Published: February 2020

Abstract
A methodology following International Cooperation on Harmonization for Veterinary Products (VICH) guidelines for the stability evaluation of colistin sulfate in a nonaqueous suspension pharmaceutical dosage form for veterinary use (via their drinking water) is described. This method monitors the percentage of colistin sulfate during the stability study of the preparation in drinking water and establishes the shelf life of the final product by a new high-performance liquid chromatography method which was developed and validated for the simultaneous determination of colistin sulfate [colistin A (Polymixin E1) and colistin B (Polymixin E2)] and methylparaben (Nipagin&lt;sup/&gt;) using a diode array detector (DAD). The method uses a Kromasil C18 column and isocratic elution. The mobile phase consisted of an acetonitrilesodium sulfate anhydrous solution (25 + 75) pumped at a flow rate of 1.5 mL/min. The DAD was set at 215 nm. The validation study was carried out according to the VICH guidelines in order to prove that the new analytical method meets the reliability characteristics, which include the fundamental criteria for validation: selectivity, linearity, precision, accuracy, and sensitivity. The method was applied during the quality control or stability studies of the suspension dosage form in order to quantify the drug (colistin) and preservative, and proved to be suitable for rapid and reliable quality control.
Simultaneous Determination of Nitroimidazole Residues in Honey Samples by High-Performance Liquid Chromatography with Ultraviolet Detection
Authors: Zhou Jinhui , Shen Jianzhong , Xue Xiaofeng , Zhao Jing , Li Yi , Zhang Jinzhen , Zhang Suxia 
Published: February 2020

Abstract
A rapid and sensitive high-performance liquid chromatography (LC) method was developed for the simultaneous determination of metronidazole (MNZ), dimetridazole (DMZ), ronidazole (RNZ), tinidazole (TNZ), and 2-hydroxymethyl-1-methyl-5-nitroimidazole (HMMNI) in honey. After extraction with ethyl acetate and evaporation, the residue containing the nitroimidazoles was dissolved in ethyl acetatehexane and subjected to solid-phase extraction cleanup by amine extraction columns. The effluent was evaporated to dryness, and residues were dissolved and determined by LC with an ultraviolet detector set at 315 nm. The limits of detection were 1.02.0 ng/g for MNZ, DMZ, RNZ, TNZ, and HMMNI in honey. Average recoveries ranged from 71.5101.4% in honey fortified at 10, 20, 50, and 100 ng/g. The method was validated for the analysis of real honey samples.
Micellar Enhanced Spectrofluorometric Determination of Labetalol Through Complexation with Aluminium(III): Application to Dosage Forms and Biological Fluids
Authors: El-Enany Nahed 
Published: February 2020

Abstract
Two simple, sensitive, and specific spectrofluorometric procedures have been developed for the determination of labetalol (LBT) in pharmaceuticals and biological fluids. LBT was found to react with Al3+ , both in acetate buffer of pH 4.5 (Procedure I) and borate buffer of pH 8.0 (Procedure II), to produce highly fluorescent stable complexes. The fluorescence intensity could be enhanced by the addition of sodium dodecyl sulfate, resulting in 3.5- and 2.7-fold increases in the fluorescence intensity for Procedures I and II, respectively. In both procedures, the fluorescence intensity was measured at 408 nm after excitation at 320 nm. The different experimental parameters affecting the development and stability of the fluorescent products were carefully studied and optimized. The fluorescence intensity-concentration plots were rectilinear over the range of 0.020.1 and 0.010.05 g/mL with a detection limit of 0.003 and 0.001 g/mL for Procedures I and II, respectively. The proposed method was successfully applied to commercial tablets containing LBT. The results were in good agreement with those obtained using a reference spectrofluorometric method. Furthermore, the method was applied for the determination of LBT in spiked human plasma, and the recovery (n = 4) was 93.30 2.62%. A proposal of the reaction pathway was postulated for Procedures I and II, respectively.
Gas-Liquid Chromatographic Determination of Milk Fat and Cocoa Butter Equivalents in Milk Chocolate: Interlaboratory Study
Authors: Buchgraber Manuela , Androni Simona ,   Collaborators:, Berndt E-M , Kaufmann-Horlacher I , Lomnitz A , Matissek R , Maurer R , Neuberger G , Rodriguez-Estrada M T , Schreiner M , Schulokat S , Schut M , Wachter N 
Published: February 2020

Abstract
A collaborative trial was conducted to validate an analytical approach comprising method procedures for determination of milk fat and the detection and quantification of cocoa butter equivalents (CBEs) in milk chocolate. The whole approach is based on (1) comprehensive databases covering the triacylglycerol composition of a wide range of authentic milk fat, cocoa butter, and CBE samples and 947 gravimetrically prepared mixtures thereof; (2) the availability of a certified cocoa butter reference material for calibration; (3) an evaluation algorithm, which allows reliable quantitation of the milk fat content in chocolate; (4) a subsequent correction to take account of the triacylglycerols derived from milk fat; (5) mathematical expressions to detect the presence of CBEs in milk chocolate; and (6) a multivariate statistical formula to quantitate the amount of CBEs in milk chocolate. Twelve laboratories participated in the validation study. CBE admixtures were detected down to a level of 0.5 g CBE/100 g milk chocolate, without false-positive or -negative results. The applied quantitation model performed well at the statutory limit of 5 CBE addition to milk chocolate, with a prediction error of 0.7, and HorRat values ranging from 0.8 to 1.5. The relative standard deviation for reproducibility (RSDR) values for quantitation of CBEs in analyses of chocolate fat solutions ranged from 2.2 to 3.8 and for analyses of real chocolate samples, from 4.1 to 4.7, demonstrating that the whole approach, based solely on chocolate fat blends, is applicable to real milk chocolate samples.
Evaluation of Serum as a Potential Matrix for Multiresidue Determination of Fluoroquinolone Antibiotics in Chicken Using Liquid Chromatography-Fluorescence-Mass Spectrometryn
Authors: Schneider Marilyn J , Reyes-Herrera Ixchel , Donoghue Dan J 
Published: February 2020

Abstract
An efficient multiresidue method was successfully applied to the determination of fluoroquinolones (FQs) in chicken serum. In this method, FQs are extracted from matrix with ammoniacal acetonitrile, and the extracts are defatted and then evaporated. After addition of basic phosphate buffer and filtration, the samples are analyzed by liquid chromatography-fluorescence-mass spectrometryn (multiple mass spectrometry; MSn). This approach allows for simultaneous quantitation (fluorescence) and confirmation (MSn) of the FQs. Using this method, 8 FQs were determined in fortified chicken serum at levels of 10, 20, 50, and 100 ng/g. Recoveries ranged from 7199, with excellent relative standard deviations (&lt;10). Limits of quantitation for the FQs ranged from 0.055 ng/g. Confirmation was achieved by comparison of MS2 or MS3 product ion ratios with those of standard FQ samples. These quantitative and confirmatory results were compared with those obtained for muscle using this approach. Serum and muscle samples from enrofloxacin-dosed chickens were also analyzed with this method. The results show that enrofloxacin can be determined in both serum and muscle of chickens dosed at a level formerly approved by the U.S. Food and Drug Administration, for up to at least 48 h after withdrawal from dosing, and suggest that serum can provide an efficient matrix for monitoring FQ levels in chicken.
Detection of Actaea racemosa Adulteration by Thin-Layer Chromatography and Combined Thin-Layer Chromatography-Bioluminescence
Authors: Verbitski Sheryl M , Gourdin Gerald T , Ikenouye Larissa M , McChesney James D , Hildreth Jana 
Published: February 2020

Abstract
Actaea racemosa L. (black cohosh; syn. Cimicifuga racemosa L. Nutt.) is a native North American perennial whose root and rhizome preparations are commercially available as phytomedicines and dietary supplements, primarily for management of menopausal symptoms. Despite its wide use, methods that accurately identify processed A. racemosa are not well established; product adulteration remains a concern. Because of its similar appearance and growing locales, A. racemosa has been unintentionally mixed with other species of the genus, such as Actaea pachypoda Ell. (white cohosh) and more commonly Actaea podocarpa DC. (yellow cohosh). The genus Actaea also has 23 temperate species with numerous common names, which can also contribute to the misidentification of plant material. Consequently, a variety of Actaea spp. are common adulterants of commercially available black cohosh preparations. Thin-layer chromatography (TLC) and combined TLC-bioluminescence (Bioluminex) are efficient, economical, and effective techniques which provide characteristic patterns and toxicity profiles for each plant species. These data indicate that common black cohosh adulterants, such as yellow cohosh, can be differentiated from black cohosh by TLC and TLC-bioluminescence. This study also showed that unknown contaminants that were not detected using standard A. racemosa identity techniques were readily detected by TLC and TLC-bioluminescence.
Comparison of Digestibility and Quality of Intact Proteins with Their Respective Hydrolysates
Authors: Potier Myléne , Tomé Daniel 
Published: February 2020

Abstract
Quality of proteins depends on their composition in essential amino acids and on the availability of amino acids. Great interest has been shown in the role played by hydrolysates of proteins in clinical diets for pathologies with reduced absorptive capacity and food allergies caused by intact protein epitopes. Milk proteins are the most important protein source used in the development of protein hydrolysates designed for nutritional support of patients. Several studies have shown that casein and whey hydrolysates have a composition in amino acids equivalent to that in native milk proteins and that digestibility is similar or better. Among plant proteins, soy is the major source of hydrolysates. Soy hydrolysates are also used in infant formulas. Plant hydrolysates have good functional properties and a nutritional quality similar to that of starting material. Some technical improvements in production of hydrolysates, particularly for plants, are nevertheless necessary to improve product palatability.
Simultaneous Estimation of Acetylsalicylic Acid and Clopidogrel Bisulfate in Pure Powder and Tablet Formulations by High-Performance Column Liquid Chromatography and High-Performance Thin-Layer Chromatography
Authors: Patel Rashmin B , Shankar Madhira B , Patel Mrunali R , Bhatt Kashyap K 
Published: February 2020

Abstract
This paper describes validated high-performance column liquid chromatographic (HPLC) and high-performance thin-layer chromatographic (HPTLC) methods for simultaneous estimation of acetylsalicylic acid (ASA) and clopidogrel bisulfate (CLP) in pure powder and formulations. The HPLC separation was achieved on a Nucleosil C8 column (150 mm length 4.6 mm id, 5m particle size) using acetonitrilephosphate buffer, pH 3.0 (55 + 45, v/v) mobile phase at a flow rate of 1.0 mL/min at ambient temperature. The HPTLC separation was achieved on an aluminum-backed layer of silica gel 60F254 using ethyl acetatemethanoltolueneglacial acetic acid (5.0 + 1.0 + 4.0 + 0.1, v/v/v/v) mobile phase. Quantitation was achieved with UV detection at 235 nm over the concentration range 424 g/mL for both drugs, with mean recoveries of 99.98 0.28 and 100.16 0.66 for ASA and CLP, respectively, using the HPLC method. Quantitation was achieved with UV detection at 235 nm over the concentration range of 4001400 ng/spot for both drugs, with mean recoveries of 99.93 0.55 and 100.21 0.83 for ASA and CLP, respectively, using the HPTLC method. These methods are simple, precise, and sensitive, and they are applicable for the simultaneous determination of ASA and CLP in pure powder and formulations.
Simultaneous Determination of Free Carnitine and Total Choline by Liquid Chromatography/Mass Spectrometry in Infant Formula and Health-Care Products: Single-Laboratory Validation
Authors: Andrieux Pierre , Kilinc Tamara , Perrin Christian , Campos-Giménez Esther 
Published: February 2020

Abstract
A single-laboratory validation study was conducted for a liquid chromatographic/mass spectrometric (LC/MS) method for the simultaneous determination of the free carnitine and total choline in milk-based infant formula and health-care products. The sample preparation used for both carnitine and choline was adapted from AOAC Official Method 999.14, with an acidic and enzymatic hydrolysis of esterified forms of choline. Carnitine and choline were quantified by ion-pair chromatography with single-quadrupole MS detection, using their respective deuterated internal standards. The repeatability relative standard deviation was 2.5 and 2.1, respectively, for carnitine and choline. The intermediate reproducibility relative standard deviation was &lt;4.7 and 2.4, respectively, for carnitine and choline. The ranges of the average product-specific recoveries were 9298 and 94103, respectively, for carnitine and choline. Choline concentration determined in infant formula reference material SRM 1846 was in agreement with the reference value. The proposed method was compared with the enzymatic methods for a range of products; good correlation (r = 0.99) was obtained, although a significant bias was observed for both analytes. The method, with a short chromatographic run time (7 min), is convenient for routine analysis to enhance analytical throughput and is a good alternative to enzymatic assays.
Spectrophotometric and Column High-Performance Liquid Chromatographic Methods for Simultaneous Estimation of Metoprolol Tartrate and Hydrochlorothiazide in Tablets
Authors: Garg Gopal , Saraf Shailendra , Saraf Swarnlata 
Published: February 2020

Abstract
Simple, accurate, economical, and reproducible UV spectrophotometric and column high-performance liquid chromatographic (HPLC) methods were developed for simultaneous estimation of a 2-component drug mixture of metoprolol tartrate and hydrochlorothiazide in combined tablet dosage form. The first method used the simultaneous equation method with 7 mixed standards and the absorption maxima at 223 and 271 nm, respectively, for metoprolol tartrate and hydrochlorothiazide in methanol. Linearity was observed in the concentration ranges of 424 and 216 g/mL for metoprolol tartrate and hydrochlorothiazide, respectively. The developed HPLC method used a reversed-phase C18 column and methanolwater (95 + 5) mobile phase at an ambient temperature of 27 2C and UV detection at 225 nm; the run time was 10 min, and quantification was based on peak area. The injection repeatability and intraday and interday repeatability were calculated. Paracetamol was used as an internal standard for the HPLC method, and linearity was observed in the concentration range of 550 g/mL for metoprolol and 220 g/mL for hydrochlorothiazide. The proposed methods were successfully applied for the determination of metoprolol tartrate and hydrochlorothiazide in bulk powder and dosage form. The results obtained were analyzed statistically, and there was no significant difference between the 2 methods. The validation was performed according to International Conference on Harmonization guidelines.
Development of a Selective and Sensitive Spectrophotometric Method for the Trace Determination of Thallium(III) Using 3-Methyl-2-benzothiazolinone Hydrazone Hydrochloride and N-(1-naphthyl)-ethylenediamine Dihydrochloride
Authors: Nagaraja Padmarajaiah , Al-Tayar Naef Ghllab Saeed , Kumar Anantharaman Shiva 
Published: February 2020

Abstract
A simple, selective, sensitive, and rapid spectrophotometric method has been developed for the determination of thallium(III) using 3-methyl-2-benzothiazolinone hydrazone hydrochloride and N-(1-naphthyl)-ethylenediamine dihydrochloride. The obtained product had an absorption maximum of 590 nm. Beer's law was valid over the concentration range of 0.158 g/mL. The molar absorptivity and Sandell's sensitivity of the colored system were 2.93 104 L/molcm and 0.00723 g/mL, respectively. The effect of different acids on the sensitivity of the method, interference by foreign substances, the optimum reaction conditions, and other analytical parameters were evaluated. The proposed method has been successfully applied in the analysis of Tl(III) in standard reference materials, synthetic mixtures, and water and urine samples. The performance of the proposed method was evaluated in terms of Student's t-test and variance ratio F-test, which indicated the significance of the proposed method over reported methods.