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Orvosi Hetilap
Authors: Lajos Markó, Gergő Attila Molnár, Zoltán Wagner, Tamás Kőszegi, Zoltán Matus, Márton Mohás, Mónika Kuzma, István András Szijártó, and István Wittmann

mtsai: Population prevalence of albuminuria in the Australian Diabetes, Obesity, and Lifestyle (AusDiab) study: immunonephelometry compared with high-performance liquid chromatography. Am. J. Kidney Dis., 2006, 47 , 604

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glycosylated vitamin B 6 in wheat by high-performance liquid chromatography. Cereal Chem. , 72 , 217–223. Lorenz K. Analysis of free and glycosylated vitamin B6 in wheat by high-performance

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Batey, I.L., Gupta, R.B., MacRitchie, F. 1991. Use of size-exclusion high-performance liquid chromatography in the study of wheat flour proteins: An improved chromatographic procedure. Cereal Chem. 68 :207

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Acta Chromatographica
Authors: Chen Cheng, Nie Cun-Xi, Liang Jing, Wang Yong-Qiang, Liu Yan-Feng, Ge Wen-Xia, and Zhang Wen-Ju

developed report of the determination of gossypol carried out on animal plasma [ 9 – 11 ], tissue [ 11 , 12 ], and the cottonseed [ 8 , 13 ] and oil [ 14 ] was mostly based on high-performance liquid chromatography (HPLC) [ 11 , 13 ], high performance

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[ 8 ], gas chromatography-electron capture detection (GC-ECD) [ 9 ], gas chromatography-mass spectrometry (GC-MS) [ 10 ], gas-liquid chromatography (GLC) [ 11 ], high-performance liquid chromatography (HPLC) [ 12–14 ], and ultra-high-performance liquid

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-electron capture detection (GC-ECD) [ 9 ], gas chromatography-mass spectrometry (GC-MS) [ 10 ], gas-liquid chromatography (GLC) [ 11 ], high-performance liquid chromatography (HPLC) [ 12–14 ], and ultra-high-performance liquid chromatography-quadrupole time of

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validated to give reliable and reproducible data [ 7 ]. High performance liquid chromatography (HPLC) and HPLC-MS/MS are the widely used methods to quantify Esomeprazole in biological fluids [ 8–11 ]. As development of analytical method is evolving through

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This study describes the development and validation of some analytical methods as high-performance thin-layer chromatography (HPTLC), ultraviolet (UV)–densitometry, UV–high-performance liquid chromatography (HPLC), and derivative spectrophotometry elaborated for the estimation of lormetazepam in pharmaceutical formulations. HPTLC method was performed using silica plates, a mobile phase composed of acetonitrile‒water (6:4, v/v), and a densitometric detection at 241 nm. UV‒derivative spectrophotometry method was applied, and at first, the direct spectrum was recorded, then first-, second-, and third-derivative spectra were obtained and measured by peak-zero (P-0) or peak-peak (P-P) techniques. Moreover, HPLC method was performed using a Gemini C18 column and isocratic elution mode with a mobile phase composed of acetonitrile–water (65:35, v/v) and delivered at a flow rate of 0.5 mL min−1. In the case of HPTLC analysis, the quantification was achieved with acceptable precision (relative standard deviation [RSD] = 5.39%) and recovery of 98.53%, using a nonlinear calibration curve. For the UV‒derivative spectrophotometry method, all derivatives and wavelengths studied proved good linearity, precision (RSD = 2.30–6.13), and recovery (91.17–98.70%). On the other hand, the elaborated HPLC method provided good results of precision (RSD = 2.16%) and recovery of 97.60% in the concentration range of 1.95–62.5 μg mL−1 using linear regression analysis. It was concluded that the best results were found for HPLC method; however, all the developed methods can be considered comparable and successfully applied to the routine quality control of this drug in dosage form.

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Two sensitive, specific, and selective stability-indicating chromatographic methods were developed for the determination of cyclobenzaprine HCl (CZ) and asenapine maleate (AS) in pure forms, in the presence of their degradation products and in their pharmaceutical formulations. The first method was an isocratic reversed-phase high-performance liquid chromatography (RP-HPLC). Analysis was performed on cyano column using a mobile phase consisting of acetonitrile–(0.05 m) potassium dihydrogen phosphate buffer (pH 3 ± 0.1) (70:30, v/v) with a flow rate of 1.5 mL min−1 and ultraviolet (UV) detection at 290 nm for the determination of CZ, and methanol–(0.05 m) potassium dihydrogen phosphate buffer (pH 6 ± 0.1) (70:30, v/v) with a flow rate of 1.5 mL min−1 and UV detection at 220 nm for the determination of AS. The second method was thin-layer chromatography (TLC), using silica gel 60 F254 plates and toluene–methanol–chloroform-ammonia solution 33% (5:3:6:0.1, by volume) as the mobile phase for the two drugs. The spots were scanned densitometrically at 290 and 220 nm for the determination of CZ and AS, respectively. The methods were validated according to the International Conference on Harmonization (ICH) guidelines, and the acceptance criteria for linearity, accuracy, precision, specificity, and system suitability were met in all cases. The linearity ranges were 2.5–25 μg mL−1 for the RP-HPLC method and 5–50 μg band−1 for the TLC method for both drugs. The limits of detection for the RP-HPLC method were 0.250 and 0.578 for CZ and AS, respectively, while the limits of quantification were 0.758 and 1.572 for CZ and AS, respectively. The limits of detection for the TLC method were 1.355 and 1.284 for CZ and AS, respectively, while the limits of quantification were 4.472 and 3.891 for CZ and AS, respectively. The results were compared statistically at a 95% confidence level with the reported methods. There were no significant differences between the mean percentage recoveries and the precisions of the two methods.

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Two novel, sensitive, and selective stability-indicating chromatographic methods were described for the analysis of zopiclone (ZOP) in the presence of its degradation products, namely, 7-oxo-6,7-dihydro-5H-pyrrolo[3,4-b]pyrazin-5-yl-4-methylpiperazine-1-carboxylate (hydrolytic DEG) and 5H-pyrrolo[3,4-b]pyrazine-5,7(6H)-dione (oxidative DEG), in drug substance and product. The first method was an isocratic reversed-phase high-performance liquid chromatography (RP-HPLC) using Inertsil ODS3 (250 × 4 mm, 5 μm) column. Upon using HPLC, the run time could be reduced, and actually, the solvents consumption decreased. Quantification was achieved by detection wavelength at 237 nm, based on peak area. Chromatographic separation was performed over the range of 1–10 μg mL−1 with limits of detection (LOD) and quantification (LOQ) of 0.18 and 0.55 μg mL−1 and a mean recovery of 99.98 ± 0.55. The analysis was achieved at 30°C using a mixture of acetonitrile and water (50:50 v/v) as the mobile phase. The second method was thin-layer chromatography (TLC) applied for the separation and analysis of zopiclone in the presence of its alkaline, acidic, and oxidative degradation products. Chromatography was performed on silica gel 60 F254 plates with ethyl acetate‒methanol‒ammonia 33% (17:2:1 v/v) as the mobile phase. Successful resolution was observed with significant difference in the R F values, followed by densitometric measurement at 303 nm. Evaluation was carried out over the range of 0.1–2 μg per spot with a mean recovery of 100.52% ± 0.24. The developed methods were successfully applied to the analysis of ZOP in bulk powder, laboratory-prepared mixtures containing different percentages of its degradation products, and pharmaceutical dosage form. The degradation products were separated by HPLC as well as identified by TLC, infrared (IR), and mass spectrometry (MS) to confirm its structures and elucidate degradation pathway. The developed methods were validated as per the International Conference on Harmonization (ICH) guidelines. The results obtained by the proposed methods were statistically compared with the reported methods revealing high accuracy and good precision.

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