bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimization and Validation of an RP-HPLC Method for Direct Determination of Metformin Hydrochloride in Human Urine and in a Dosage Form
Authors: El-Gindy Alaa , Nassar Mohammed Wafaa , El-Abasawy Nasr Mohammed , Attia Khalid Abdel-Salam , Al-Shabrawi Maisra 
Published: February 2020

Abstract
A simple, selective, sensitive, accurate, and precise method was developed for determination of metformin hydrochloride (MF) in human urine using RP-HPLC. The method depends upon using an octylsilyl (C8) 5 m particle size column at ambient temperature with mobile phase consisting of 33 mM sodium dihydrogen phosphate containing 6.38 mM hexanesulfonic acid sodium salt and adjusted to apparent pH 3.0 with phosphoric acidacetonitrile (93 7, v/v) at a flow rate of 1.5 mL/min. Quantitation was achieved with UV detection at 231 nm based on peak area with a linear calibration curve over the concentration range of 0.0150 g/mL. The proposed method was applied to the determination of the urinary excretion pattern of MF (the cumulative amounts excreted were calculated without pretreatment of the urine sample) and for determination of the dissolution pattern of MF tablets. The proposed method was completely validated according to the U.S. Food and Drug Administration guidelines.
Stress Degradation Studies and Kinetic Determinations of Duloxetine Enteric-Coated Pellets by HPLC
Authors: Gomes Patrícia , Wingert Nathalie R , Paim Clésio S , Schapoval Elfrides E S , Steppe Martin 
Published: February 2020

Abstract
A stability-indicating HPLC assay method was developed for the quantitative determination of duloxetine (DLX) in a pharmaceutical dosage form in the presence of its degradation products, and kinetic determinations were evaluated in acid conditions and UV-C radiation exposure. Chromatographic separation was achieved by use of an ACE&lt;sup/&gt; C18 column (250 4.0 mm id, 5 m particle size). The mobile phase was prepared by mixing aqueous 50 mM potassium phosphate buffer (pH 6.0 containing 0.3 triethylamine) and acetonitrile (60 40, v/v). DLX was rapidly degraded in an acid medium and in the presence of hydrogen peroxide and UV-C radiation; it was more stable in alkaline medium. The described method was linear over a range of 4.014.0 g/mL for determination of DLX (r = 0.9998). The precision was demonstrated by the RSD of intraday (0.791.07) and interday (0.85) studies. The mean recovery was found to be 100.56. The acid degradation of DLX in 0.1 M HCl solution showed an apparent zero-order kinetics (k = 0.177 g/mL/min), and the photodegradation demonstrated an apparent first-order kinetics (k = 0.082 g/mL/min). The developed method was found to be simple, specific, robust, linear, precise, and accurate for the determination of DLX in enteric-coated pellets.
Quantitative Analysis of the Cholesterol-Lowering Drugs Ezetimibe and Simvastatin in Pure Powder, Binary Mixtures, and a Combined Dosage Form by Spectrophotometry, Chemometry, and High-Performance Column Liquid Chromatography
Authors: Lotfy Hayam Mahmoud , Alamein Amal Mahmoud Aboul , Hegazy Maha Abdel Monem 
Published: February 2020

Abstract
Simple, accurate, sensitive, and precise UV spectrophotometric, chemometric, and HPLC methods were developed for simultaneous determination of a two-component drug mixture of ezetimibe (EZ) and simvastatin (SM) in laboratory-prepared mixtures and a combined tablet dosage form. Four spectrophotometric methods were developed, namely, ratio spectra derivative, ratio subtraction, isosbestic point, and mean centering of ratio spectra. The developed chemometric-assisted spectrophotometric method was the concentration residual augmented classical least-squares method; its prediction ability was assessed and compared to the conventional partial least-squares method. The developed HPLC method used an RP ZORBAX C18 column (5 m particle size, 250 4.6 mm id) with isocratic elution. The mobile phase was acetonitrilepH 3.5 phosphate buffer (40 60, v/v) at a flow rate of 1.0 mL/min, with UV detection at 230 nm. The accuracy, precision, and linearity ranges of the developed methods were determined. The developed methods were successfully applied for determination of EZ and SM in bulk powder, laboratory-prepared mixtures, and a combined dosage form. The results obtained were compared statistically with each other and to those of a reported HPLC method; there was no significant difference between the proposed methods and the reported method regarding both accuracy and precision.
Effect of Gamma Irradiation on Caprolactam Migration from Multilayer Polyamide 6 Films into Food Simulants: Development and Validation of a Gas Chromatographic Method
Authors: Félix1 Juliana S , Monteiro Magali , Manzoli José E , Padula Marisa 
Published: February 2020

Abstract
A GC method to determine caprolactam in water, 15 ethanol, and olive oil food simulants was developed and validated. Linear ranges varied from 0.96 to 642.82 g/mL for water, 0.64 to 800.32 g/mL for 15 ethanol, and 1.06 to 1062.34 g/g for olive oil, with correlation coefficients higher than 0.999. Method precision studies showed RSD values lower than 5.45, while method accuracy studies showed recovery from 72 to 111 for all simulants. The effect of gamma irradiation on caprolactam migration from multilayer polyamide 6 (PA-6) films intended for cheese into water, 15 ethanol, olive oil, and 3 acetic acid simulants was also studied. For migration assay, non-irradiated and irradiated (12 kGy) films were placed in contact with the simulant and exposed at 40C for 10 days. The validated method was used to quantify caprolactam migration from multilayer PA-6 films into the simulants, which ranged from 1.03 to 7.59 mg/kg for non-irradiated films, and from 4.82 to 11.32 mg/kg for irradiated films. Irradiation caused almost no changes in caprolactam levels, with the exception of olive oil, which showed an increase in the caprolactam level. All multilayer PA-6 films were in accordance with the requirements of the legislation for caprolactam migration.
Determination of Aflatoxin in Processed Dried Cassava Root: Validation of a New Analytical Method for Cassava Flour
Authors: Gnonlonfin G J Benoit , Katerere David R , Adjovi Yann , Brimer Leon , Shephard Gordon S , Sanni Ambaliou 
Published: February 2020

Abstract
A new method that uses HPLC with a photochemical reactor for enhanced detection was developed and validated for the determination of aflatoxins in cassava flour. Samples were spiked with a mixture of four aflatoxins at 5, 10, and 20 g/kg mixed with either 1 or 5 g NaCl and extracted with methanolwater (80 20, v/v) by shaking for 10 or 30 min. An immunoaffinity column was used for cleanup. HPLC with postcolumn derivatization, for enhancement of aflatoxin fluorescence, and fluorescence determination were used for quantitation of the toxin concentration. The method was validated for recovery, linearity, and precision at the three concentrations tested. Recovery ranges were 5270, 6985, and 8089 for the spiking levels of 5.0, 10.0, and 20.0 g/kg, respectively. It appears that the amount of salt (NaCl) and the shaking time are critical factors in this method; optimal performance was obtained when 1 g salt was used and the shaking time was 10 min. The good linearity and precision of the method allowed baseline separation from interferences, e.g., coumarins.
Optical Determination of L-tyrosine Based on Eggshell Membrane Immobilized Tyrosinase
Authors: Li Yong Jin 
Published: February 2020

Abstract
An optical biosensor based on the eggshell membrane immobilized tyrosinase is described for the detection of L-tyrosine (L-Tyr). The detection scheme was based on the measurement of absorption value of color adduct resulting from the reaction of 3-methyl-2-benzothiazolinone hydrazone and dopa-quinone produced from the enzymatic oxidation of L-Tyr. The prepared biosensor demonstrated optimum activity at pH 7, optimum temperature range of 2040C and a linear response for the L-Tyr concentration in range of 5200 M. It also showed good operation stability for repeated measurements (over 300 times) and storage stability after it had been kept at 4C for 3 months.
Modification of the BAX® System PCR Assay for Detecting Salmonella in Beef, Produce, and Soy Protein Isolate
Authors: Peng Linda X , Wallace Morgan , Andaloro Bridget , Fallon Dawn , Fleck Lois , Delduco Dan , Tice George 
Published: February 2020

Abstract
The BAX® System PCR assay for Salmonella detection in foods was previously validated as AOAC Research Institute (RI) Performance Tested MethodSM (PTM) 100201. New studies were conducted on beef and produce using the same media and protocol currently approved for the BAX System PCR assay for E. coli O157:H7 multiplex (MP). Additionally, soy protein isolate was tested for matrix extension using the U.S. Food and Drug Administration-Bacteriological Analytical Manual (FDA-BAM) enrichment protocols. The studies compared the BAX System method to the U.S. Department of Agriculture culture method for detecting Salmonella in beef and the FDA-BAM culture method for detecting Salmonella in produce and soy protein isolate. Method comparison studies on low-level inoculates showed that the BAX System assay for Salmonella performed as well as or better than the reference method for detecting Salmonella in beef and produce in 8–24 h enrichment when the BAX System E. coli O157:H7 MP media was used, and soy protein isolate in 20 h enrichment with lactose broth followed by 3 h regrowth in brain heart infusion broth. An inclusivity panel of 104 Salmonella strains with diverse serotypes was tested by the BAX System using the proprietary BAX System media and returned all positive results. Ruggedness factors involved in the enrichment phase were also evaluated by testing outside the specified parameters, and none of the factors examined affected the performance of the assay.
Chemical Composition and Antibacterial Activity of Origanum saccatum P.H. Davis Essential Oil Obtained by Solvent-Free Microwave Extraction: Comparison with Hydrodistillation
Authors: Sozmen Fazli , Uysal Burcu , Oksal Birsen S , Kose Elif Odabas , Deniz I Gokhan 
Published: February 2020

Abstract
The components of the essential oils (EOs) obtained by solvent-free microwave extraction (SFME) and hydrodistillation (HD) from endemic Origanum saccatum P.H. Davis were identified by using GC/MS. The main constituents of both EOs obtained by SFME and HD, respectively, from O. saccatum were p-cymene (72.5 and 70.6%), thymol (9.32 and 8.11%), and carvacrol (7.18 and 6.36%). The EO obtained by SFME contained substantially higher amounts of oxygenated compounds and lower amounts of monoterpenes than did the EO obtained by HD. The antibacterial activities of the EOs obtained by SFME and HD were evaluated with the disc diffusion method by comparison with 10 different bacterial strains. The antibacterial activity of the EO extracted by SFME was found to be more effective than that of the EO extracted by HD against seven of the tested bacteria.
Optimization and Validation of a Multiclass Screening and Confirmation Method for Drug Residues in Milk Using High-Performance Liquid Chromatography/Tandem Mass Spectrometry
Authors: Clark Susan B , Storey Joseph M , Turnipseed Sherri B 
Published: February 2020

Abstract
The further optimization and validation of a multiresidue veterinary drug screening method for milk is described. The drug residues of regulatory interest in milk include -lactams, sulfonamides, tetracyclines, fluoroquinolones, and macrolides. A previously published procedure has been modified to incorporate new compounds and to collect both screening and confirmatory ion transitions in one acquisition method. Milk samples were extracted with an equal volume of acetonitrile. The samples were then subjected to cleanup with a bonded SPE cartridge and a MW cutoff filter. The SPE protocol was modified to effectively recover a metabolite of flunixin. Established tolerance levels are set for most of these drugs in milk; thus, the screening procedure was semiquantitative, using positive controls for comparison. The positive controls, consisting of extracts from milk fortified with the drugs at their tolerance or safe level, were used to set statistically valid minimum response criteria for unknown samples. This updated method was validated with fortified milk, as well as with milk samples from animals administered veterinary drugs.
Substitute Technology for Reference Substances in the Analysis of Impurities in Cefonicid for Injection with HPLC Using a Diode Array Detector
Authors: Li Wei 
Published: February 2020

Abstract
With HPLC using a diode array detector (DAD), a method of substitution for reference substances in impurity profiling control was developed that combined peak tracking by the correlation of spectra with application of correction factors for determination of each impurity. For qualitative analysis, two-dimensional (2D) standard spectrochromatographic data produced by HPLC-DAD were compared with sample data to develop 2D chromatographic spectral correlative maps so that the three target impurities were recognized without preparation and injection of reference solutions. For quantitative analysis, correction factors among cefonicid and the three impurities were established. The correction factors were 1.06 for 5-mercapto-1,2,3,4-tetrazole 1-methyl sulfonic acid detected at 255 nm, 0.77 for 7-aminocephalosporanic acid detected at 265 nm, and 0.97 for methoxycefonicid detected at 268 nm. The method could be used in analysis of related substances in cefonicid for injection without recourse to chemical reference standards of the three impurities.
Capillary Methods for Drug Analysis
Authors: Hendrickx Ans , Mangelings Debby , Heyden Yvan Vander 
Published: February 2020

Abstract
This review gives an overview of the applicability of capillary electrophoresis, capillary liquid chromatography, capillary electrochromatography, and their derived techniques to analyze drug impurity mixtures, formulations, biological samples, and chiral compounds. For each application type, a few examples are given to illustrate the potential of the capillary technique. Details are provided about the capillaries used, chiral selectors, and stationary and mobile phases.
Development and Validation of an HPLC Method for Determination of Ziprasidone and Its Impurities in Pharmaceutical Dosage Forms
Authors: Pavlovic Marija , Malesevic Marija , Nikolic Katarina , Agbaba Danica 
Published: February 2020

Abstract
Ziprasidone is known as a novel “atypical” or “second-generation” antipsychotic drug. A sensitive and reproducible method was developed and validated for determination of ziprasidone and its major impurities, which are significantly different in polarity. The separation is performed on a Waters Spherisorb® octadecylsilyl 1 column (5.0 μm particle size, 250 × 4.6 mm id) using a gradient with mobile phase A [buffer–acetonitrile (80 + 20, v/v)] and mobile phase B [buffer–acetonitrile (10 + 90, v/v)] at a working temperature of 25°C. The buffer was 0.05 M KH2PO4 solution with an addition of 10 mL triethylamine/L solution, adjusted to pH 2.5 with orthophosphoric acid. The flow rate was 1.5 mL/min, and the eluate was monitored at 250 nm using a diode array detector. Optimization of the experimental conditions was performed using partial least squares regression, for which four factors were selected for optimization: buffer concentration, buffer pH, triethylamine concentration, and temperature. The proposed validated method is convenient and reliable for the assay and purity control in both raw materials and dosage forms.
Chemometric Detection of Acetaminophen in Pharmaceuticals by Infrared Spectroscopy Combined with Pattern Recognition Techniques: Comparison of Attenuated Total Reflectance-FTIR and Raman Spectroscopy
Authors: Komsta Łukasz , Czarnik-Matusewicz Henryk , Szostak Roman , Gumieniczek Anna , Pietraš Rafał , Skibiński Robert , Inglot Tadeusz 
Published: February 2020

Abstract
This paper presents and discusses the building of discriminant models from attenuated total reflectance (ATR)–FTIR and Raman spectra that were constructed to detect the presence of acetaminophen in over-the-counter pharmaceutical formulations. The datasets, containing 11 spectra of pure substances and 21 spectra of various formulations, were processed by partial least squares (PLS) discriminant analysis. The models found in the present study coped greatly with the discrimination, and their quality parameters were acceptable. A root mean square error of cross-validation was in the 0.14–0.35 range, while a root mean square error of prediction was in the 0.20–0.56 range. It was found that standard normal variate preprocessing had a negligible influence on the quality of ATR-FTIR; in the Raman case, it lowered the prediction error by 2. The influence of variable selection with the uninformative variable elimination by PLS method was studied, and no further model improvement was found.
Monolithic Spin Column: A New Extraction Device for Analysis of Drugs in Urine and Serum by GC/MS and HPLC/MS
Authors: Namera Akira , Nagao Masakata , Nakamoto Akihiro , Miyazaki Shota , Saito Takeshi 
Published: February 2020

Abstract
A monolithic spin column was developed for the extraction of analytes from biological materials. This column was constructed by packing a monolithic silica disk into a spin column. Sample loading, washing, and elution of the target drugs were accomplished simply by centrifugation of the column. Opiates and benzodiazepines are abused throughout the world. Identification and quantification of these drugs is very important to solve crimes or the cause of death. Three opiates (morphine, codeine, and dihydrocodeine) were extracted from urine and serum by using the column. After conversion to trimethylsilyl derivatives of the opiates by vigorous mixing with the derivatizing reagent, the solution was subjected to GC/MS. A linear curve was observed for opiates from 10 to 2500 ng/mL in urine and 5 to 1200 ng/mL in serum, respectively (correlation coefficient &gt; 0.996). For benzodiazepines, the hydroxyl metabolites of triazolam and etizolam were extracted from urine using the column, and the eluate was directly analyzed by HPLC/MS without evaporation. The LOD values were at the ppb level, with RSD values lower than 15%. The proposed methods were successfully applied to clinical and forensic cases, and good agreement of results was obtained compared to conventional methods.
Development and Validation of a UHPLC Method for the Determination of Flavonoids in Red Wine
Authors: Baranowska Irena , Magiera Sylwia 
Published: February 2020

Abstract
A simple and fast ultra-high-performance liquid chromatography (UHPLC) method was developed for the identification and quantification of the following flavonoids in red wine: (±)-catechin, (–)-epicatechin, rutin, quercitrin, hesperidin, neohesperidin, (±)-naringenin, hesperetin, and chrysin. Chromatographic separation of the flavonoids was performed on a Chromolith® Fast Gradient C18e column. A gradient elution was used with mobile phases consisting of 0.1% formic acid in water and acetonitrile. UV detection was performed at 280 nm. A complete separation of flavonoids was possible within 6 min. The calibration curves showed good linearity (R2 ≥ 0.9990) in the selected range of each analyte; the LOD ranged between 0.06 and 0.19 μg/mL. An optimized sample preparation method utilized SPE. The Oasis HLB column with the highest recoveries was selected for the preconcentration step. This method was successfully applied to the determination of these flavonoids in the red wine samples with excellent results.
Determination of Enantiomers of Atenolol and Propranolol in Pharmaceutical Formulations by HPLC
Authors: Torul Hilal , Tamer Uğur 
Published: February 2020

Abstract
A validated HPLC-UV method was developed for the determination of R(–), S(+)-atenolol and R(–), S(+)-propranolol in pharmaceutical formulations. The proposed method required no elaborate sample preparation and was found to be selective, linear, and repeatable within the established ranges. Atenolol and propranolol isomers were separated using a Chirex 3022 (S) column with the mobile phases hexane–dichloromethane–methanol–trifluoroacetic acid (35 + 35 + 5 + 0.25, v/v/v/v) and hexane–dichloromethane–ethanol–trifluoroacetic acid (55 + 40 + 5 + 0.25, v/v/v/v), respectively. The LOD values of R(–) and S(+)-atenolol were 12.3 and 9.86 μg/mL, respectively, and 0.61 and 0.89 μg/mL, respectively, for R(–) and S(+)-propranolol. Retention times of R(–)-propranolol and S(+)-propranolol were 12.4 and 14.3 min, respectively, and 29.06 and 32.71 min, respectively, for (R)-atenolol and (S)-atenolol. The proposed method was applied to the determination of enantiomers in pharmaceutical formulations, and no interference from any excipients was found.
Determination of Fumonisins B1 and B2 in Corn-Based Foods for Infants and Young Children by LC with Immunoaffinity Column Cleanup: Interlaboratory Validation Study
Authors: Solfrizzo Michele , De Girolamo Annalisa , Gambacorta Lucia , Visconti Angelo , Stroka Joerg , van Egmond Hans P ,   Collaborators:, Bouten K , Breidbach A , Burdaspal P , Çimen D , MacDonald S , Mujahid C , Nuotio K , Patel; S , Pereboom-de Faw D , Pietri A , Schnaufer R , Seefelder W , Senyuva H Z , Sizoo E , Thim A M 
Published: February 2020

Abstract
A liquid chromatographic method for the determination of fumonisins B1 (FB1) and B2 (FB2) in corn-based foods for infants and young children was subjected to an interlaboratory validation study involving 11 laboratories. Five blind duplicate sample pairs of each matrix were analyzed to establish the accuracy, repeatability, and reproducibility of the method. Mass fractions in the baby food samples ranged from 89.1 to 384.4 μg/kg FB1 and from 22.5 to 73.6 μg/kg FB2. The method involved a warm extraction with citrate phosphate buffer–methanol–acetonitrile (50 + 25 + 25, v/v/v), a cleanup through an immunoaffinity column, and an end-determination of fumonisins by LC after automated precolumn derivatization with-o-phthaldialdehyde reagent. RSDs for within- laboratory repeatability (RSDr) ranged from 6.8 to 23.5% for FB1 and 7.6 to 22.9% for FB2. RSDs for between-laboratory reproducibility (RSDR) ranged from 15.4 to 26.2% for FB1 and 21.6 to 36.3% for FB2. Mean FB1 recoveries from baby foods spiked at 100.0 and 250.0 μg/kg were 89 and 96%, respectively; for FB2 spiked foods at 25.0 and 62.5 μg/kg recoveries were 90 and 85%, respectively. HorRat values ranged from 0.8 to 1.2 for FB1, whereas for FB2 they ranged from 0.9 to 1.4 when calculated according to Horwitz, and from 1.0 to 1.7 when calculated according to Thompson, indicating an acceptable among- laboratory precision for all matrixes (HorRat values &lt;2).