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

Efficient Synthesis of Potential Impurities in Levonadifloxacin (WCK 771)

Levonadifloxacin (WCK 771) is a novel broad-spectrum anti-methicillin-resistant Staphylococcus aureus (MRSA) agent recently launched in India. Five process impurities and one degradation impurity were synthesized as reference standards for their quantification by high-performance liquid chromatography (HPLC) methodology in drug substance and drug product. These compounds are not easily commercially available. The synthesis and characterization of these impurities are discussed in detail.

Reverse-phase chiral high-performance liquid chromatography for separation of a diastereomer in alalevonadifloxacin: A novel antibacterial agent

Alalevonadifloxacin (ALA) is a novel antibacterial drug, recently launched in India to treat infections caused by Gram-positive bacteria. In present work, a chiral high-performance liquid chromatographic method was developed and validated for the quantification of a diastereomeric impurity (DI) in ALA. The separation was achieved on Pirkle type (R,R) Whelk-O1 chiral stationary phase, using ammonium formate buffer and acetonitrile in gradient fashion at a flow rate of 1.5 ml/min. The method was extensively validated for the quantification of DI in ALA. The detector response for DI was linear over the concentration range of 0.24-4.78 μg/ml. Limit of quantitation and limit of detection for DI were 0.24 and 0.07 μg/ml respectively. The mean recovery of the DI was 103.47 ± 5.14%. The impact of column temperature on the chiral separation was evaluated. The method was employed for controlling diastereomeric impurity in the batches of ALA used in preclinical studies.

Enantiomeric resolution of quinolones on crown ether CSP: Thermodynamics, chiral discrimination mechanism and application in biological samples

The enantiomers of quinolone racemates were resolved using chiral crown ether within 8 min. Thermodynamics data and modeling results were used to determine chiral recognition mechanism. The column used was (+)-Crownpack column (250 mm × 4.6 mm, 5 µm) with three mobile phases I: ACN:Water (80:20) + 10 mM H₂SO₄ and 10 mM CH₃COONH₄, II: ACN:Water (80:20) + 20 mM perchloric acid and III: EtOH:Water (80:20) + 20 mM perchloric acid. The flow rate of the mobile phases was 1.0 mL/min with UV detection at different wavelengths. The ranges of retention (k), separation (α), and resolution (Rs) factors were 1.00-5.40, 1.37-2.00 and 1.50-3.30. The tailing factor was 1.o for all peaks with 900-2325 as the number of theoretical plates were 8.0-10.0 and 32.4-22.1 µg. The difference in enthalpy, entropy and free energy varied in the range of -0.350 to -0.024, 18.74 × 10^-4 to 3.94 × 10^-4 and -0.918 to -0.143, respectively. The thermodynamic and docking results showed chiral discrimination due to physical forces of amnio group cations penetration into the chiral cavity of the chiral selector following hydrogen bindings. The binding energy of S-enantiomers was higher than R-enantiomers; confirming stronger binding of S-enantiomers with CSP than R-enantiomers. The described chiral-HPLC method was used for the analysis of the quinolone enantiomers in urine samples and the results were quite satisfactory. Therefore, the reported method may be used for the enantiomeric separation of quinolone enantiomers in urine samples.

Chemistry, Biological Properties and Analytical Methods of Levonadifloxacin: A Review

Increased use of antibiotics globally has led to the threat of antibiotic resistance; this drove the urge of researchers toward discovering more potent and broad-spectrum antibiotics. Levonadifloxacin (LND) is the very first antibiotic developed by an Indian company Wockhardt. It is S (-) isomer of another broad-spectrum antibiotic Nadifloxacin which is used topically for skin, soft tissue bacterial infection. LND belongs to the benzo quinolizine category which is a subclass of fluoroquinolone, indicated for ABSSIS, CABP, and other infections including diabetic foot infection; formulated as l-arginine salt of levonadifloxacin (WCK177) for IV and l-alanine ester mesylate salt as alalevonadifloxacin (WCK2349) for oral administration. It generally shows dominant antibacterial activity against Gram-negative, and positive bacterial infections, particularly toward methicillin-resistant Staphylococcus aureus (MRSA) by dual inhibition of DNA gyrase and topoisomerase IV. Producing quality product that complies to regulatory requirements is a big concern for pharma industries. To this context, validated analytical methods for routine quality control are essential for quantification of LND as an API alone and together with pharmaceutical formulations. This review suggests therapeutic, pharmacological, and analytical aspects regarding the novel drug LND and particularly focuses on discussing various reported analytical methods present for analytical or bioanalytical estimation of the drug and suggest to develop a simple and validated method which also complies to green chemistry.

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.

Liquid Chromatographic Enantioseparation of Some Fluoroquinoline Drugs Using Several Polysaccharide-Based Chiral Stationary Phases

The enantioseparation of three fluoroquinoline antibacterial drugs, namely, flumequine, ofloxacin and lomefloxacin using high-performance liquid chromatography was optimized on seven polysaccharide-derived chiral stationary phases, namely, Chiralpak® IB, chiralpak® IA, Chiralpak® AD, Chiralcel® OJ, Chiralcel® OD, Chiralcel® OD-H and Chiralcel® OZ-3 and applying different mobile phases in isocratic mode is described. The role of addition of organic additives was also investigated. A baseline separation of flumequine, ofloxacin and lomefloxacin enantiomers was achieved. Parameters influencing enantioseparation including mobile phase, organic additive and chemical nature of the chiral selector found to be highly influencing on the enantiomeric separation were investigated. Chiral recognition mechanism(s) are also presented.

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.