Analytical chiral separation of a new quinolone compound in biological fluids by high-performance liquid chromatography

Impurity Profiling of a Novel Anti-MRSA Antibacterial Drug: Alalevonadifloxacin

Alalevonadifloxacin (ALA, formerly described as WCK 2349) is a novel antibacterial drug developed to treat infections caused by Gram-positive bacteria. The current study was aimed to identify and quantify impurities in ALA. Mass spectrometry (MS) compatible reverse phase liquid chromatographic method was developed to identify the impurities in ALA. Three impurities were identified based on the molecular ion peak and their product ions. These impurities were synthesized and characterized using MS and nuclear magnetic resonance spectrometry. However, this method was unable to resolve the diastereomeric impurity, which is likely to be formed during synthesis. Therefore, another method was developed using YMC Chiral NEA-[S] as a chiral stationary phase and validated for quantification of all impurities including diastereomeric impurity. The developed method was employed for quality control and stability studies of the ALA drug substance used in pre-clinical and clinical studies.

Chiral separation of quinolones by liquid chromatography and capillary electrophoresis

The quinolones are derivatives of oxoquinolines and mostly known for their antibacterial and antiviral activities. Many quinolones are chiral compounds having asymmetric centers and important due to their enantioselective biological activities. In order to study the biological activities of quinolone enantiomers, to control the manufacturing of homochiral drugs and to prepare necessary quantities of pure enantiomers for preclinical or clinical trials, respective chiral separation methods are urgently needed. In this context, the present review discusses chromatographic and electrophoretic methods for the enantioseparation of chiral quinolones and provides some useful information on their physical and pharmaceutical properties. The drawbacks of currently used techniques are revealed and ways to overcome them are outlined. Moreover, recommendations for an optimal choice of a separation protocol are given.

Relationship of quantitative structure and pharmacokinetics in fluoroquinolone antibacterials

AIM: To study the relationship between quantitative structure and pharmacokinetics (QSPkR) of fluoroquinolone antibacterials.

METHODS: The pharmacokinetic (PK) parameters of oral fluoroquinolones were collected from the litera-ture. These pharmacokinetic data were averaged, 19 compounds were used as the training set, and 3 served as the test set. Genetic function approximation (GFA) module of Cerius² software was used in QSPkR analysis.

RESULTS: A small volume and large polarizability and surface area of substituents at C-7 contribute to a large area under the curve (AUC) for fluoroquinolones. Large polarizability and small volume of substituents at N-1 contribute to a long half life elimination.

CONCLUSION: QSPkR models can contribute to some fluoroquinolones antibacterials with excellent pharmacokinetic properties.

Validated chiral high-performance liquid chromatography method for a novel anti-methicillin-resistant staphylococcus aureus fluoroquinolone WCK 771

A sensitive, simple, specific, precise, accurate and rugged method for the assay and determination of enantiomeric purity of S-(-)-9-fluoro-6,7-dihydro-8-(4-hydroxypiperidin-1-yl)-5-methyl-1-oxo-1H,5H-benzo[i,j]quinolizine-2-carboxylic acid L-arginine salt tetrahydrate (WCK 771) in bulk drug has been developed. The method is RP-HPLC using endcapped C-18 stationary phase and chiral mobile phase. Chirality to the mobile phase was imparted with addition of beta-cyclodextrin. The UV-vis detector was operated at 290 nm. The flow rate of mobile phase was 2 ml/min. The method offers excellent separation of two enantiomers with resolution more than 2 and tailing factor less than 1.5. The method was validated for the assay of WCK 771 and quantification of R-(+)-enantiomer impurity in bulk drug. The calibration curves showed excellent linearity over the concentration range of 0.05-0.15 mg/ml for WCK 771 and 0.5-7.5 microg/ml for R-(+)-enantiomer. The precision (RSD) of the assay was 0.23%. The limit of detection and limit of quantitation of the method for WCK 771 were 0.015 and 0.06 microg/ml, respectively. The limit of detection and limit of quantitation for R-(+)-enantiomer were 0.025 and 0.09 microg/ml, respectively. The average recovery of the R-(+)-enantiomer was 100.5%. Same method was applied for the assay and determination of enantiomeric purity of WCK 771 in the intravenous formulation.

High-performance liquid chromatographic separation of fluoroquinolone enantiomers: a review

Fluoroquinolones are antibacterial agents widely used clinically. In recent years, there has been an important development of new derivatives, and more than 7000 analogues have been described today. Different fluoroquinolones (FQ) have one or two chiral centers in their chemical structure and are available as racemates, diastereoisomers, or pure enantiomers. The clinical and pharmaceutical uses of these compounds need effective analytical procedures for quality control and pharmacodynamic and pharmacokinetic studies. This review article focuses on the high-performance liquid chromatographic separation of fluoroquinolone stereoisomers by the use of derivatization methods and ligand exchange (LE) or chiral liquid chromatography.

Development of a chiral assay for a novel, nonfluorinated quinolone, PGE-9509924, in dog plasma using high performance liquid chromatography with electrospray tandem mass spectrometry or fluorescence detection

PGE-9509924 is a nonfluorinated quinolone and is active against a variety of susceptible and drug resistant bacteria in vitro and in animal infection models. A method for determining both enantiomers of PGE-9509924 in dog plasma has been developed. The enantiomers are derivatized with a chiral derivatizing agent, (-)-1-(9-fluorenyl)ethyl chloroformate (FLEC) and the resulting diastereomers are separated by reverse phase chromatography. Plasma samples are prepared via solid phase extraction (SPE) in a 96-well format prior to being derivatized. Samples are then analyzed by electrospray-LC/MS/MS with multiple reaction monitoring or by HPLC with fluorescence detection. Results of a side-by-side validation of the method with LC/MS/MS and HPLC/Fl detection are presented. Over the range selected for validation (0.025-10 micro g/ml), both methods give similar results with identical limits of quantitation. Due to the selectivity of LC/MS/MS and the use of a stable-isotopically labeled internal standard, significantly shorter chromatographic runtimes are achieved with LC/MS/MS, making it the method of choice for sample analysis.

Chiral separation of pharmaceuticals possessing a carboxy moiety

The separation of carboxylic enantiomers in the pharmaceutical field using high-performance liquid chromatographic and capillary electrophoretic techniques is reviewed. The techniques used for chiral separation include diastereomer derivatization, a chiral mobile phase, a chiral stationary phase (high-performance liquid chromatography) and chiral additives (capillary electrophoresis). Practical and conventional separation systems for pharmaceutical applications, such as pharmacokinetics, optical purity testing and stability studies, are described. A comprehensive collection of applications to carboxylic drugs and other carboxylic compounds of pharmaceutical interest is listed in the tables. The characteristics of each enantioseparation method are also discussed briefly.