Determination of tizoxanide, the active metabolite of nitazoxanide, by micellar liquid chromatography using a monolithic column. Application to pharmacokinetic studies

2014 ◽  
Vol 6 (21) ◽  
pp. 8682-8689 ◽  
Author(s):  
Shereen Shalan ◽  
Jenny Jeehan Nasr ◽  
Fathalla Belal

In this study, a micellar liquid chromatography method is proposed for determination of tizoxanide, the active metabolite of nitazoxanide, using a mobile phase consisting of 0.1 M sodium dodecyl sulphate, 8%n-propanol and 0.3% triethylamine in 0.02 M phosphoric acid.

2013 ◽  
Vol 96 (6) ◽  
pp. 1315-1324 ◽  
Author(s):  
Mohamed I Walash ◽  
Fathalla Belal ◽  
Nahed El-Enany ◽  
Manal Eid ◽  
Rania N El-Shaheny

Abstract A stability-indicating micellar liquid chromatography (MLC) method was developed and validated for the assay of floctafenine (FLF) in the presence of its degradation product and main metabolite, floctafenic acid (FLA). The analysis was carried out on a CLC Shim-Pack octyl silane (C8) column (150 × 4.6 mm id, 5 μm particle size) using a micellar mobile phase consisting of 0.15 M sodium dodecyl sulfate, 10% n-propanol, and 0.3% triethylamine in 0.02 M orthophosphoric acid (pH = 3). The mobile phase was pumped at a flow rate of 1.0 mL/min with UV detection at 360 nm. The method showed good linearity for FLF and FLA over the concentration ranges of 0.5–25.0 and 0.4–10.0 μg/mL, with LODs of 0.16 and 0.12 μg/mL, respectively. The developed method was successfully applied to the determination of FLF in commercial dispersible tablets, with mean recovery of 98.87 ± 1.37%. Also, the proposed method was specific for the analysis of FLF in presence of the co-formulated drug thiocolchicoside in laboratory-prepared tablets, with mean recovery of 100.50 ± 1.07%. Statistical comparison of the results obtained by the proposed MLC method with those obtained by a comparison method showed good agreement. Moreover, the method was extended to study the degradation behavior of FLF under different International Conference on Harmonization recommended conditions such as alkaline, acidic, oxidative, thermal, and photolytic. The method was further applied for direct determination of FLA as the main metabolite of FLF in human plasma without prior extraction steps, with mean recovery of 110.50 ± 6.5%.


Chemija ◽  
2018 ◽  
Vol 29 (2) ◽  
Author(s):  
Audrius Markevičius ◽  
Audrius Zolumskis ◽  
Audrius Sadaunykas ◽  
Birutė Knašienė ◽  
Adrian Vicent Claramunt ◽  
...  

A fast, precise and accurate high performance liquid chromatography method has been developed for the determination of dyes (Solvent Red 19 and Solvent Blue 35) and a marker (Solvent Yellow 124) in diesel. Separation was carried out on a 250 × 4.60 mm Agilent Zorbax Rx-SIL column (5 µm particle size). Detection was done in a visible wavelength range. The best performance of fuel dye separation and the shortest retention times were achieved when using hexane, toluene and ethyl acetate as a mobile phase. During this research the eluent composition and the elution gradient were optimized consequently that helped to perform the analysis within 15 min. The developed method was applied for the analysis of real samples of dyed diesel fuel. Preparation of the samples for the analysis simply consisted of filtering through a 0.45 µm filter previous to direct injection of the sample into the HPLC system for analysis.


Author(s):  
Saleh Trefi ◽  
Yaser Bitar

Objective: The objective of this study was to develop and validate a novel ion-pair liquid chromatography method, in order to separate and assay of amlodipine/benazepril combination in capsules. This method was a fast, practical and additional choice in quality control laboratories.Methods: The chromatographic conditions comprised of a classical C18-type stationary phase (250 × 4.6 mm, 5μ), with a mobile phase consisting of: 45% of 10-3 M of cetrimide and 55% acetonitrile. The flow rate was 1 ml/min; the detection wavelength was at 242 nm, under ambient temperature.Results: The method was validated for linearity with correlation coefficients very close to one, the accuracy with mean recovery values between 95.0-105.0%, precision with relative standard deviations of the calculated concentrations less than 5.0% and specificity in the presence of degradation products and excipients.Conclusion: The results presented in this paper showed that the developed method was fast and applicable, for the separation and determination of amlodipine/benazepril combination in capsules.


2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Danielle Cristina da Silva ◽  
Cláudio Celestino Oliveira

Method for extraction and determination of amoxicillin, caffeine, ciprofloxacin, norfloxacin, tetracycline, diclofenac, ibuprofen, nimesulide, levonorgestrel, and 17α-ethynylestradiol exploiting micellar liquid chromatography with PDA detector and solid-phase extraction was proposed. The usage of toxic solvents was low; the chromatographic separation of the medicaments was performed using a C18 column and mobile phases A and B containing 15.0% (v/v) ethanol, 3.0% (m/v) sodium dodecyl sulfate (SDS), and 0.02 mol·L−1 phosphate at pHs 7.0 and 8.0, respectively. The method is simple, selective, and fast, and the analytes were separated in 23.0 min. For extraction, 1000 mL of sample containing 2.0% (v/v) ethanol and 0.002 mol·L−1 citric acid at pH 2.50 was loaded through a 1000 mg of C18 cartridge. The analytes were eluted using 3.0 mL of ethanol, which were evaporated and redissolved in 0.5 mL of mobile phase. Concentration factors better than 1200, except amoxicillin (224), were obtained. The analytical curves were linear (R2 better than 0.992); LOD and LOQ n=10 presented values in the range of 0.019–0.247 and 0.058–0.752 mg·L−1, respectively. Recoveries of 99% were obtained, and the results are in agreement with those obtained by the comparative methods.


2013 ◽  
Vol 781-784 ◽  
pp. 1708-1711 ◽  
Author(s):  
Yi Qing Yang ◽  
Qian Wang ◽  
Qiao Wang ◽  
Shi Jie Yan

HPLC (High Performance Liquid Chromatography) method for chloramphenicol residues in freshwater fish was developed. The samples were extracted with ethyl acetate. The LC was performed on a C18 column, mobile phase consisted of methanol-water (45:55 v/v) and eluted at 0.2mL/min at 20°C, inject volume was 20μl. The linear rang for chloramphenicol residual is within 0.5-20μg/mL, the limit of detection is 0.01ng/g. The average recovery is 80.06%-92.71%, and the RSD is 1.46%-5.61%. This method is employed to analyze freshwater fishes, such as catfish, chub and carp.


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