Development and validation of a RP-HPLC method for stability-indicating assay of gemifloxacin mesylate including identification of related substances by LC-ESI-MS/MS, 1H and 13C NMR spectroscopy

A validated stability indicating RP-HPLC assay of gemifloxacin mesylate was developed by separating its related substances on an Inertsil-ODS3V-C18 (4.6 × 250 mm; 5 μm) column using 0.1% trifluoroaceticacid (pH 2.5) and methanol as a mobile phase in a gradient elution mode at a flow rate of 1.0 mL/min at 27°C. The column effluents were monitored by a photodiode array detector set at 287 nm. The method was validated in terms of accuracy, precision and linearity as per ICH guidelines. Forced degradation of gemifloxacin (GFX) was carried out under acidic, basic, thermal, photolysis and peroxide conditions and the degradation products were separated and characterized by ESI-MS/MS, (1) H and (13) C NMR spectroscopy. The method was successfully applied to the analysis of bulk drugs and the recoveries of gemifloxacin and impurities were in the range of 97.60-102.90 and 96.99-102.10%, respectively. No previous reports were found in the literature on identification of degradation products of gemifloxacin.

Liquid chromatographic separation and determination of aromatic sulfonates in an aquatic environment using a photodiode array and electrospray ionization-mass spectrometer as detectors

A simple and rapid method involving high-performance liquid chromatographic separation, followed by photodiode array (PDA) and electrospray ionization-mass spectrometric (ESI-MS) detection of aromatic sulfonates in waste-water effluents of industrial units producing optical whitening agents, has been developed. The separation was achieved on a reversed-phase Hypersil C18 column using gradient elution of a mobile phase consisting of 0.05 M ammonium formate-methanol with decreasing concentration of the buffer at room temperature. The minimum detection limits were determined to be in the range of 0.2 - 1.8 x 10(-9) g using PDA and ESI-MS detectors.