Development of a liquid chromatography-tandem mass spectrometry method with modified QuEChERS extraction for the quantification of mebendazole and its metabolites, albendazole and its metabolites, and levamisole in edible tissues of aquatic animals.

A liquid chromatography-tandem mass spectrometry quantitative method was developed for determining mebendazole and its metabolites, albendazole and its metabolites, and levamisole in muscles of bluntnose black bream, shrimp, eel and turtle based on modified QuEChERS methodology. The method included 2 g of the muscle matrix with 10 mL acetonitrile, and 0.8 g of magnesium sulphate and 0.2 g of sodium chloride for liquid-liquid partitioning. After vortex and centrifugation, the resulting liquid (5.5 mL) was purified by C18 (50 mg) and Al-N (50 mg). The limits of detection were lower than 0.3 µg kg-1 and the limits of quantitation were no more than 1 µg kg-1 for all analytes. The recoveries of the analytes ranged from 80.0% to 113.7% with the relative standard derivation less than 10.0%. The preparation procedure provided efficient extraction and purification that enabled a sensitive and rugged determination of target compounds.

Diarrea por infección parasitaria múltiple / Diarrhea caused by multiparasitic infection

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Selective extraction and concentration of mebendazole in seawater samples using molecularly imprinted polymer as sorbent.

A high selective pre-treatment method for the extraction and analysis of mebendazole in environmental water samples was developed based on molecularly imprinted solid-phase extraction (MISPE). The mebendazole imprinted polymers were synthesized in acetonitrile using methacrylic acid and ethylene glycol dimethacrylate as functional monomer and cross-linker respectively. The imprinted materials showed high adsorption ability for mebendazole and were applied as special solid-phase extraction sorbents for selective separation of mebendazole. An off-line MISPE procedure was developed for the purification and enrichment of mebendazole from natural seawater samples prior to high-performance liquid chromatography analysis. The recoveries of spiked seawater on the MISPE cartridges were from 83.0% to 90.6%, and the values of the relative standard deviation were in the range of 2.78-4.13% (n=3). The satisfied results showed that this pre-treatment methodology for extracting mebendazole in seawater was simple and effective.

Preparation, characterization and application of a new stir bar sorptive extraction based on poly(vinylphthalimide-co-N,N'-methylenebisacrylamide) monolith.

In this study, a new stir bar sorptive extraction (SBSE) coating based on poly(vinylphthalimide-co-N,N'-methylenebisacrylamide) monolith (SBSE-VPMB) was prepared. The influences of the contents of monomer in polymerization mixture and the percentage of porogen solvent on the extraction performance were investigated thoroughly. Several characteristic techniques, such as elemental analysis, scanning electron microscopy, mercury intrusion porosimetry and infrared spectroscopy, were used to characterize the monolithic material. The analysis of oxfendazole (OFZ) and mebendazole (MBZ) in milk and honey samples by the combination of SBSE with HPLC with diode array detection was selected as paradigms for the practical evaluation of the new coating. Under the optimized extraction conditions, the limits of detection (S/N=3) for OFZ and MBZ were 0.23-0.60 µg/L in milk and 0.24-1.08 µg/L in honey, respectively. The method also showed good linearity, repeatability, high feasibility and acceptable recoveries for real samples. At the same time, the extraction performance and the distribution coefficients (K(VPMB/W)) of OFZ and MBZ on SBSE-VPMB were compared with other SBSEs based on porous monoliths and commercial SBSE.

Identification of the mebendazole polymorphic form present in raw materials and tablets available in South Africa.

A preformulation study of four different raw materials of mebendazole showed that three samples were polymorph C and the other polymorph A, or a mixture of form A and B. X-ray powder diffractometry and infrared spectroscopy indicated that this powder could be form B, but powder dissolution, for which a much slower dissolution was obtained, suggests polymorph A. Literature prescribes the use of polymorph C pharmaceutically, but generic manufacturers should be aware that forms other than C are still available on the market. The four mebendazole tablets currently available in South Africa were also tested and it was found that all of them contained polymorph C.

Two high-performance liquid chromatographic determinations for mebendazole and its metabolites in human plasma using a rapid Sep Pak C18 extraction.

A rapid extraction procedure for mebendazole and its metabolites from plasma using Sep Pak C18 is described. This method eliminates the need for solvent extractions as such. Two reversed-phase high-performance liquid chromatographic determinations for these extracts, one isocratic elution and the other gradient elution, using an analytical wavelength of 254 nm are also presented. The gradient elution system provides superior resolution of these compounds and consequently has improved determination limits. For mebendazole the determination limits are 20 ng/ml (isocratic system) and 10 ng/ml (gradient system).