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. Budai A.: LCMS bevezetése a Gábor Dénes Főiskolán (Introduction of a LCMS at Dennis Gabor Collage). MTA SZTAKI 4. e-Learning Forum , 16 June 2004 Budapest. EN-402 Language Instructions. http
formulations, several analytical methods were reported including, HPLC [ 9–11 ], UV spectrophotometry [ 10, 12 ], and HPTLC [ 13–14 ]. To the best of our knowledge, no methods have been reported regarding simultaneous single quad LC-MS determination of the
Summary
The present study was designed to characterize the possible degradation products of zolpidem tartrate under various stress conditions according to International Conference on Harmonization (ICH) guidelines Q1A(R2). After exposure to light, heat, hydrolysis, and oxidation, the drug significantly degraded under photolytic and acid/base hydrolytic conditions. Degradation resulted in the formation of four key degradants. Degradation products were resolved from each other and the drug by employing an isocratic elution method on Luna C18 column with mobile phase consisting of methanol-10 mM ammonium acetate (68.4:31.6, v/v), wherein pH was adjusted to 5.4 with glacial acetic acid. To characterize the degradation products, a method was extended to LC-MS and a mass fragmentation pattern was established using single quadrupole. The degradants were identified as zolpacid, oxozolpidem, zolpaldehyde, and zolpyridine. Finally, the most possible degradation mechanism of zolpidem tartrate in different environments was proposed.
Summary
In this paper we describe a sensitive and reproducible reversed-phase high-performance liquid chromatography (HPLC) method with photodiode-array detection for isolation and quantification of the bioactive hydrophilic constituent 7-(1-O-β-d-galacturonide-4′-(1-O-β-d-glucopyranosyl)-3′,4′,5,7-tetrahydroxyflavone, 1, from the seeds of Cuminum cyminum. Compound 1 was separated isocratically on a C18 preparative column, in high purity, after removal of solvents. The purity and identity of the compound were established by use of LC-mass spectrometry and by spectroscopic techniques (1H and 13C NMR). The purity of 1 was also confirmed by HPTLC.
A sensitive and simple liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) method for determination of dasatinib in rat plasma using one-step protein precipitation was developed. After addition of carbamazepine as internal standard (IS), protein precipitation by acetonitrile was used as sample preparation. Chromatographic separation was achieved on an SB-C18 (2.1 mm × 150 mm, 5 μm) column with methanol-0.1% formic acid as mobile phase with gradient elution. Electrospray ionization (ESI) source was applied and operated in positive ion mode; selective ion monitoring (SIM) mode was used to quantification using target fragment ions m/z 488.2 for dasatinib and m/z 338.7 for the IS. Calibration plots were linear over the range of 10–1000 ng mL−1 for dasatinib in rat plasma. Lower limit of quantification (LLOQ) for dasatinib was 10 ng mL−1. Mean recovery of dasatinib from plasma was in the range 82.2%–93.6%. Relative standard deviation (RSD) of intra-day and inter-day precision were both less than 8%. This developed method is successfully used in pharmacokinetic study of dasatinib in rats.
Chinese Pharmacopoeia [ 1 ]. Several liquid chromatography (LC) methods, including LC with ultraviolet detection (LC-UV) and LC with mass spectrometry (LC-MS) [ 7–12 ], were developed for the determination of andrographolide and dehydroandrographolide in
-performance liquid chromatography [HPLC], etc.) or hyphenated with spectroscopic equipment (gas chromatography–mass spectrometry [GC–MS], LC–MS, etc.) offer a viable solution. Since its first discovery in Russia by Tswett in 1900 [ 17 ], chromatography has enjoyed
). [48]. A. Polettini (ed.), Applications of LC-MS in Toxicology , Pharmaceutical Press, 2006 . [49]. J.T. Prince
Abstract
Let f(x) be the product of several linear polynomials with integer coefficients. In this paper, we obtain the estimate log lcm (f(1),…,f(n))∼An as n→∞, where A is a constant depending on f.
work up, samples were injected into the LCMS/MS for analysis. Chiral-AGP column and a mobile phase of ammonium formate buffer (10 mM, pH 4.70 ± 0.05)-acetonitrile (85:15, v / v and 70:30, v / v ) in a gradient time program [ 28 ] was successful to
