A high-performance liquid chromatographic method was optimized and validated for the determination of desacetyl nitazoxanide (tizoxanide), the main active metabolite of nitazoxanide in human plasma, urine and breast milk. The proposed method used a CN column with mobile phase consisting of acetonitrile-12mM ammonium acetate-diethylamine in the ratio of 30:70:0.1 (v/v/v) and buffered at pH 4.0 w...

In this study we present a simple and rapid method for tissue lipid extraction. Snap-frozen tissue (15-150 mg) is collected in 2 ml homogenization tubes. 500 μl BUME mixture (butanol:methanol [3:1]) is added and automated homogenization of up to 24 frozen samples at a time in less than 60 seconds is performed, followed by a 5-minute single-phase extraction. After the addition of 500 μl heptane:...

A relatively simple and rapid procedure for the measurement of free ammonium and the amides in plant extracts is described. The method was developed by combining a cation-exchange method for blood ammonia with a differential acid-hydrolysis procedure for asparagine and glutamine amide-nitrogen. The recovery of standard samples (100-400 mug of ammonium- or amide-nitrogen) of free ammonium, aspar...

Efficacy assessments using a combination of baricitinib and methotrexate necessitate the development of an analytical method for the determination of both drugs in plasma with precision. A high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous determination of baricitinib and methotrexate in rat plasma. Extraction of baricitinib, met...

A selective, sensitive and high throughput liquid chromatography-tandem mass spectrometry (LC-ESI-MS/MS) method has been developed for separation and quantification of metoprolol enantiomers on a chiral Lux Amylose-2 (250 mm×4.6 mm, 5 μm) column. Solid phase extraction of (S)-(-)- and (R)-(+)-metoprolol and rac-metoprolol-d6 as an internal standard (IS) was achieved on Lichrosep DVB HL cartridg...

A sensitive and high throughput ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method has been developed for the determination of sirolimus in human whole blood. The method involved protein precipitation with ZnSO4, followed by solid phase extraction of sirolimus along with tacrolimus as the internal standard (IS) from 100 μL of human blood. The chromatographic an...

The present paper describes the development and validation of a new reversed-phase liquid chromatography-electrospray ionization tandem mass spectrometric method (RP-HPLC-ESI-MS/MS) for simultaneous determination of pyridine, 2-picoline, 4-picoline and quinoline from mainstream cigarette smoke. Liquid-liquid extraction followed by solid-phase extraction was applied to extract the target analyte...

preparation of tretinoin-containing microspheres with the aim of reducing undesirable skin reactions towards trans retinoic acid (tra) and thus, improving patient compliance is of particular interest. these microspheres have to be smaller than 30 m m to avoid causing gritty feel when applying on the skin, and slow the release of drug to minimize its skin side effects. following preliminary eval...

A simple and precise analytical method for the determination of 5'deoxy-5-fluorocytidine (DFCR) and 5'deoxy-5-fluorouridine (DFUR), the enzymatically formed metabolites of capecitabine in plasma, was developed using a reversed-phase high performance liquid chromatography gradient method with external standard method. Blood samples were analyzed after separation of DFCR/DFUR by solid-phase extra...

A simple and rapid ultra-performance liquid chromatographic tandem mass spectrometric assay for the measurement of bisphenol-A (BPA) in human urine was developed and validated. Sample preparation involved addition of 4-nitrophenol (as an internal standard, IS) to 1.0 ml human urine sample containing BPA, and extraction with ethyl acetate and hexane (6:4,v:v), evaporation, and dissolving the res...