High-Performance Liquid Chromatographic Determination of Memantine in Human Urine Following Solid-Phase Extraction and Precolumn Derivatization

2013 ◽  
Vol 96 (6) ◽  
pp. 1302-1307 ◽  
Author(s):  
Karim Michail ◽  
Hoda Daabees ◽  
Youssef Beltagy ◽  
Magdy Abd Elkhalek ◽  
Mona Khamis

Abstract A validated HPLC-UV method is presented for the quantification of urinary memantine hydrochloride, a novel medication approved to treat moderate and advanced cases of Alzheimer's disease. The drug and amantadine hydrochloride, the internal standard, were extracted from human urine using SPE. The extract was then buffered and derivatized at room temperature using o-phthalaldehyde in the presence of N-acetyl-L-cyteine. Chromatographic separation of the formed derivatives was achieved on a C18 column using methanol–water mobile phase adjusted to pH 7 and pumped isocratically at 1 mL/min. The UV detector was set at 340 nm. The chromatographic run time did not exceed 10 min. The LOD and LOQ were 8 and 20 ng/mL, respectively. The RSDs for intraday and interday precisions did not exceed 5.5%. The method was used to monitor memantine hydrochloride in human urine in order to determine an appropriate sampling interval for future noninvasive therapeutic drug monitoring. The assay could also be applied to the determination of amantadine. The described assay showed that a postdosing time interval of 25–75 h seems adequate for sampling and monitoring memantine in urine.

2003 ◽  
Vol 68 (11) ◽  
pp. 883-892 ◽  
Author(s):  
Dragica Zendelovska ◽  
Trajce Stafilov

A rapid, specific and sensitive high-performance liquid chromatographic method for the determination of famotidine in human plasma has been developed. Famotidine and the internal standard were chromatographically separated from plasma components using a Lichrocart Lichrospher 60 RP select B cartridge for solid-phase separation with a mobile phase composed of 0.1 % (v/v) triethylamine in water (pH 3) and acetonitrile (92:8, v/v). UV detection was set at 270 nm. The calibration curve was linear in the concentration range of 10.0 ? 350.0 ng mL-1. The method was implemented to monitor the famotidine levels in patient samples.


1980 ◽  
Vol 63 (1) ◽  
pp. 47-48
Author(s):  
James M Zehner ◽  
Richard A Simonaitis ◽  
Roy E Bry

Abstract A high performance liquid chromotographic method is presented for determining bendiocarb (2,2-dimethyl-1,3-benzodioxol-4-yl methylcarbamate) on wool. Bendiocarb is extracted from wool with methanol containing methyl benzoate as internal standard, eluted through a Zorbax ODS column with methanol-water (55 + 45), and detected with a UV detector at 280 nm. The method can be used to determine bendiocarb at 0.001–0.02% by weight. The limit of detection is 0.0004%, or 4 ppm. At 4 analyses each, recovery at 0.013% was 101%, standard deviation 2.8%; at 0.003%, recovery was 96%, standard deviation 5.6%; at 0.001%, recovery was 103%, standard deviation 2.9%.


2020 ◽  
Vol 16 (8) ◽  
pp. 1106-1112
Author(s):  
Ibrahim A. Darwish ◽  
Nasr Y. Khalil ◽  
Mohammad AlZeer

Background: Axitinib (AXT) is a member of the new generation of the kinase inhibitor indicated for the treatment of advanced renal cell carcinoma. Its therapeutic benefits depend on assuring the good-quality of its dosage forms in terms of content and stability of the pharmaceutically active ingredient. Objective: This study was devoted to the development of a simple, sensitive and accurate stabilityindicating high-performance liquid chromatographic method with ultraviolet detection (HPLC-UV) for the determination of AXT in its bulk and dosage forms. Methods: Waters HPLC system was used. The chromatographic separation of AXT, internal standard (olaparib), and degradation products were performed on the Nucleosil CN column (250 × 4.6 mm, 5 μm). The mobile phase consisted of water:acetonitrile:methanol (40:40:20, v/v/v) with a flow rate of 1 ml/min, and the UV detector was set at 225 nm. AXT was subjected to different accelerated stress conditions and the degradation products, when any, were completely resolved from the intact AXT. Results: The method was linear (r = 0.9998) in the concentration range of 5-50 μg/ml. The limits of detection and quantitation were 0.85 and 2.57 μg/ml, respectively. The accuracy of the method, measured as recovery, was in the range of 98.0-103.6% with relative standard deviations in the range of 0.06-3.43%. The results of stability testing revealed that AXT was mostly stable in neutral and oxidative conditions; however, it was unstable in alkaline and acidic conditions. The kinetics of degradation were studied, and the kinetic rate constants were determined. The proposed method was successfully applied for the determination of AXT in bulk drug and dosage forms. Conclusions: A stability-indicating HPLC-UV method was developed and validated for assessing AXT stability in its bulk and dosage forms. The method met the regulatory requirements of the International Conference on Harmonization (ICH) and the Food and Drug Administration (FDA). The results demonstrated that the method would have great value when applied in quality control and stability studies for AXT.


Author(s):  
Klaudia Kokoszka ◽  
Agnieszka Kobus ◽  
Sylwia Bajkacz

The residues of antimicrobials used in human and veterinary medicine are popular pollutants of anthropogenic origin. The main sources of introducing antimicrobials into the environment are sewage treatment plants and the agricultural industry. Antimicrobials in animal manure contaminate the surrounding soil as well as groundwater, and can be absorbed by plants. The presence of antimicrobials in food of plant origin may pose a threat to human health due to their high biological activity. As part of the research, a procedure was developed for the extraction and determination of ciprofloxacin, enrofloxacin, cefuroxime, nalidixic acid and metronidazole in environmental samples (soil and parsley root). An optimized solid-liquid extraction (SLE) method was used to separate antimicrobials from the solid samples and a mixture of citrate buffer (pH = 4): methanol (1:1; v/v) was used as the extraction solvent. Solid phase extraction (SPE) with OASIS® HLB cartridges was used to purify and pre-concentrate the sample. The recovery of the developed method was in the range of 55–108%. Analytes were determined by high-performance liquid chromatography coupled with an ultraviolet (UV) detector and a tandem mass spectrometer (HPLC-UV-MS/MS). The procedure was validated and applied to the determination of selected antimicrobials in soil and parsley root samples. Five types of soil and five types of parsley roots of different origins were analyzed. The presence of nalidixic acid in the parsley root samples was found in the concentration range of 0.14–0.72 ng g−1. It has been shown that antimicrobials are absorbed by the plant and can accumulate antimicrobials in its edible parts.


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