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Summary

A new sensitive and specific isocratic RP-HPLC-UV method was developed and validated for the determination of ondansetron in rabbit plasma using risperidone as an internal standard (IS). The sample preparation involved a simple deprotenization procedure with a mixture of 1 mL of acetonitrile and 50 μL of 10% w/υ zinc sulfate. Analysis was performed on a Phenomenex CN column (250 mm × 4.6 mm, 5 μm) with 50 mM ammonium acetate (pH 3.5) and acetonitrile (35:65, υ/υ) as mobile phase at a flow rate of 1.0 mL min−1. Column eluent was monitored at 310 nm. The calibration curve was linear over the concentration range of 25–1000 ng mL−1 (r 2 = 0.9999) with a limit of quantification (LOQ) 25 ng mL−1. The intraday and interday precision and accuracy were between 0.93% and 3.41% and −3.63% and 1.01%, respectively. The mean recoveries of ondansetron and risperidone were 85.87% and 99.80%, respectively. Ondansetroncontaining plasma samples were stable at −20°C for 14 days. The validated method was successfully applied for a pharmacokinetic study after a single oral administration of ondansetron (8 mg) to rabbits.

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element in analytical industrial applications. Therefore, the aim of this work was to simultaneously resolve and validate three statins including atorvastatin, rosuvastatin, and simvastatin using a simple RP-HPLC containing greener organic solvent and a

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, accurate, and reliable method for simultaneous determination of metalaxyl, captan, and folpet residues in table grape samples using RP-HPLC and UV–DAD has been developed and validated. Successful separation and quantification were achieved using isocratic

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Summary

An isocratic reversed-phase high-performance liquid chromatographic (RPHPLC) method for analysis of irinotecan HCl has been developed and validated. Separation was achieved on a C18 column with potassium dihydrogen phosphate buffer (pH adjusted to 3.5 with orthophosphoric acid)-acetonitrile-methanol 55:25:20 (v/v) as mobile phase at a flow rate of 1.0 mL min−1. UV detection was performed at 254 nm. The method is simple, sensitive, rapid, and selective, and linear over the range 30–70 μg mL−1 for assay of irinotecan HCl. The precision of the assay method was below 1.0% RSD. Mean recovery was in the range 98.0–102.0%. Recovery of the active pharmaceutical ingredient from dosage forms ranged from 99.0 to 101.0. The method is useful for quality control in bulk manufacture and of the pharmaceutical formulation.

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A simple, rapid, precise, and accurate, stability-indicating reversed phase high performance liquid chromatographic method was developed and validated for simultaneous determination of metformin HCl and repaglinide. The chromatographic separation was achieved on YMC Pack AM ODS (5 μm, 250 mm length × 4.6 mm i.d.) column at a detector wavelength of 210 nm, using an isocratic mobile phase consisting of methanol and 10 mM potassium dihydrogen phosphate buffer (pH 2.5) in a ratio of 70:30 v/v at a flow rate of 1 mL min−1. The retention times for metformin and repaglinide were found to be 2.6 and 11.3 min, respectively. The drugs were exposed to thermal, photolytic, hydrolytic, and oxidative stress conditions, and the stressed samples were analyzed by the proposed method. Validation of the method was carried out as per International Conference on Harmonization (ICH) guidelines. Linearity was established for metformin and repaglinide in the range of 5–200 μg mL−1 and 1–200 μg mL−1, respectively. The limits of detection were 0.3 μg mL−1 and 0.13 μg mL−1 for metformin and repaglinide, respectively. The method was found to be specific and stability-indicating as no interfering peaks of degradants and excipients were observed. The proposed method is hence suitable for application in quality-control laboratories for quantitative analysis of both the drugs individually and in combination, since it is simple and rapid with good accuracy and precision.

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Acta Chromatographica
Authors: A. B. Thomas, U. B. Chavan, R. K. Nanda, L. P. Kothapalli, S. N. Jagdale, S. B. Dighe, and A. D. Deshpande

Summary

Simultaneous analysis of atenolol (Atn), hydrochlorothiazide (Hctz) and losartan potassium (Los) in solid dosage forms has been achieved by reversed-phase high-performance liquid chromatography on a C18 column with a 0.035 M potassium dihydrogen orthophosphate-acetonitrile gradient as mobile phase and UV detection at 225 nm. The retention times for Atn, Hctz, and Los were 2.91, 4.75, and 7.52 min, respectively, with mean recoveries of 99.67, 99.89, and 100.69%. The method was validated in accordance with ICH guidelines. Because of its simplicity and high precision and accuracy, the method can be used for analysis of atenolol, hydrochlorothiazide and losartan potassium in pharmaceutical preparations.

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Summary

Andrographolide and betulinic acid are the terpenoids having potential anti-cancer activity. The cytotoxicity activity of both the drugs was carried out separately and in combination on liver cancer HepG2 cell lines. High-performance liquid chromatography (HPLC) and high-performance thin-layer chromatography (HPTLC) methods were developed and validated for simultaneous estimation of these two terpenoids as per the International Conference on Harmonization (ICH) guidelines, which was applied for quantification in nanoformulation. The retention time by HPLC and retardation factor by HPTLC for andrographolide and betulinic acid were found to be 2.2 and 6.6 min, and 0.24 ± 0.01 and 0.66 ± 0.01, respectively. Both the methods were validated for accuracy, precision, repeatability, robustness, limit of detection (LOD), and limit of quantitation (LOQ). The content of andrographolide and betulinic acid in nanoformulation was found to be 96.0% and 98.0% by HPLC and 96.59% and 98.33% by HPTLC, respectively, of labelled claim.

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Summary

Linear gradient HPLC on a C8 column has been used for separation of individual related substances of amoxicillin listed in the European Pharmacopoeia and a newly identified degradation impurity. The USP plate count for the amoxicillin peak was more than 3000 and USP tailing for the same peak was less than 2.0. Forced degradation studies were conducted on amoxicillin drug substance using ICH stress study guidelines to demonstrate the specificity and stability-indicating nature of the method. A new impurity observed after thermal and alkaline degradation was identified as N-pivaloylamoxicillin. The LOD and LOQ for individual related substances were below 0.045 and 0.086% (w/w), respectively. The method was fully validated in accordance with ICH analytical method validation guidelines. The results of the study prove the method is specific, precise, linear, robust, and can be used for evaluation of the stability of amoxicillin drug substance.

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The aim of this study was to compare efficiency of RP-HPLC (Reversed-Phase High-Performance Liquid Chromatography) and LOC (Lab-on-Chip) methods for wheat gluten protein quantification regarding clustering of wheat cultivars according to the genetic similarity (HMW-GS combinations), as well as to explore relations of these two methods to wheat quality parameters. For that purpose, wheat quality parameters (protein content, falling number, wet gluten content, gluten index, Farinograph, Extensograph, and Amylograph), as well as amounts of gliadin and glutenin fractions by RP-HPLC and LOC methods were determined in two different sets of wheat cultivars (Croatian and Serbian). The percentages of gluten proteins and the values of quality parameters were used to characterize the samples by principal component analysis (PCA). Gluten protein quantification performed by method based on the protein fraction separation by molecular weights (LOC) was better for grouping of genetically similar wheat cultivars than quantification of proteins separated by their different solubility in specified solvent gradient (RP-HPLC). LOC method showed higher potential in wheat quality prediction.

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Summary

Ezetimibe is the first in a new class of antihypercholesterolemic drugs. Since it has not long been available on the market, many of its properties may still be revealed. Analytical methods for its determination are scarce, especially regarding serum samples. A simple, fast, and effective high-performance liquid chromatography-ultraviolet (HPLC-UV) method for the determination of ezetimibe concentration in human serum has therefore been developed. Three mobile phases were analysed, and original modifications to the concentration and flow parameters were made. Of five potential internal standards (IS), only nitrendipine was found to be suitable. The analytical wavelength was chosen based on the absorption spectrum of ezetimibe in the mobile phase. Finally, an extraction analysis was performed using two different solvents, and the extrahent volume was optimised. The final method developed was as follows. Single extraction of 1 mL serum sample, spiked with IS, was performed using 10 mL of methyl-t-butyl ether. Separation was obtained at ambient temperature on a Waters C18 Symmetry Shield (4.6 mm × 250 mm, 5 μm) column. The isocratic mobile phase was composed of acetonitrile and 0.1 M ammonium acetate aqueous solution 55:45 (v/v), set at flow rate of 0.75 mL min−1. Ezetimibe was detected at a wavelength of 232 nm after 5.49 min, and the IS was detected at 8.05 min. The developed method has been validated according to ICH standards. It was found to be specific, precise, accurate and linear over the range 10–800 ng mL−1 with R 2 > 0.998, and detection and quantification limits of 4.60 ng mL−1 and 13.94 ng mL−1, respectively. The method has been applied to clinical serum samples. The developed technique allowed for successful in vivo assessment of ezetimibe concentrations in samples obtained from hypercholesterolemia patients who are chronically receiving the drug.

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