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Biomed Chromatogr

A highly sensitive and efficient UPLC-MS/MS assay for rapid analysis of tedizolid (a novel oxazolidinone antibiotic) in plasma sample.

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A highly sensitive and efficient UPLC-MS/MS assay for rapid analysis of tedizolid (a novel oxazolidinone antibiotic) in plasma sample.

Biomed Chromatogr. 2016 Apr 23;

Authors: Iqbal M

Abstract
Tedizolid (TDZ) is a novel oxazolidinone class antibiotic, indicated for the treatment of acute bacterial skin and skin structure infections (ABSSSI) in adults. In this study a highly sensitive UPLC-MS/MS assay was developed and validated for the determination of TDZ in rat plasma using rivaroxaban as an internal standard (IS). Both TDZ and IS were separated on Acquity UPLC BEH(TM) C18 column using isocratic mobile phase comprising of acetonitrile: 20 mM ammonium acetate (85:15, v/v), eluted at 0.3 mL/min flow rate. Plasma sample was processed by liquid liquid extraction technique using ethyl acetate as an extracting agent. The analyte and IS were detected in positive mode using electrospray ionization source. The precursor to product ion transitions at m/z 371.09 > 343.10 for TDZ and m/z 435.97 > 144.94 for IS, were used for the quantification in multiple reaction monitoring mode. The calibration curve was linear in the concentration range of 0.74-1500 ng/mL and the lower limit of quantification was 0.74 ng/mL only. The developed assay was validated following standard guidelines for bioanalytical method validation (USFDA) and all the validation results were within the acceptable limits. The developed assay was successfully applied into a pharmacokinetic study in rats.

PMID: 27105920 [PubMed – as supplied by publisher]

Assays for determination of ertapenem for applications in therapeutic drug monitoring, pharmacokinetics and sample stability.

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Assays for determination of ertapenem for applications in therapeutic drug monitoring, pharmacokinetics and sample stability.

Biomed Chromatogr. 2014 Aug 4;

Authors: Pickering MK, Brown SD

Abstract
Carbapanems are a class of β-lactam antibiotics with broad-spectrum potency and high β-lactamase resistance. Ertapenem, a member of this class, sold under the trade name Invanz™, has been of interest in the world of antibiotic therapeutic drug monitoring owing to its highly standardized 1 g dose and its high degree of plasma protein binding. Owing to the relative newness of this drug, fewer than 30 methods for ertapenem quantification have been published. Among these about half utilize biological matrices at the sample type. Liquid-liquid extraction and protein precipitation prevail as the most frequently used sample preparation techniques, despite their low recoveries compared with solid-phase extraction. Additionally, high-performance liquid chromatography with ultraviolet detection (HPLC-UV) is the instrumentation choice for most ertapenem assays. While these approaches may not achieve the highest possible sensitivity for ertapenem quantification, they provide clinically relevant tools for monitoring ertapenem in real patients. Sample stability is an ongoing concern for laboratories that handle ertapenem analysis, with buffering being of paramount importance, as well as low temperature (<-70°C) storage, to ensure minimal drug degradation in situ. Copyright © 2014 John Wiley & Sons, Ltd.

PMID: 25088456 [PubMed – as supplied by publisher]

Determination of chromatographic dissociation constants of some carbapenem group antibiotics and quantification of these compounds in human urine.

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Determination of chromatographic dissociation constants of some carbapenem group antibiotics and quantification of these compounds in human urine.

Biomed Chromatogr. 2013 Dec 17;

Authors: Cubuk Demiralay E, Koç D, Daldal YD, Alsancak G, Ozkan SA

Abstract
The dissociation constant values (s (s) pKa ) of some carbapenem group drugs (ertapenem, meropenem, doripenem) in different percentages of methanol-water binary mixtures (18, 20 and 22%, v/v) were determined from the mobile phase pH dependence of their retention factor. Evaluation of these data was performed using the NLREG program. From calculated pKa values, the aqueous pKa values of these subtances were calculated by different approaches. Moreover, the correlation established between retention factor and the pH of the water-methanol mobile phase was used to determine the optimum separation conditions. In order to validate the optimized conditions, these drugs were studied in human urine. The chromatographic separation was realized using a Gemini NX C18 column (250 × 4.6 mm i.d., 5 µm particles) and UV detector set at 220 and 295 nm. Copyright © 2013 John Wiley & Sons, Ltd.

PMID: 24343876 [PubMed – as supplied by publisher]