INDIRECT SPECTROFLUORIMETRIC DETERMINATION OF MOSAPRIDE CITRATE IN PHARMACEUTICAL FORMULATIONS

Mosapride citrate (MC), 4-amino-5-chloro-2-ethoxy-{N-[4-(p-fluorobenzyl)-2-morpholinyl] methyl}-benzamide, is a potent gastroprokinetic drug and it is used in gastrointestinal symptoms associated with chronic gastritis. MC is not yet official in any Pharmacopeia but there are several publications which describe methods for the determination of mosapride citrate in pure and in dosage forms. Most of the proposed methods for mosapride citrate analysis are HPLC (1) and spectrophotometric methods (2, 3). The luminescence sensitization of lanthanides (Ln) in their complex compounds with organic ligands is widely used for the determination of drugs: fluoroquinolones (4), tetracycline (5), non-steroidal anti-inflammatory preparations (6), catecholamines (7) in the dosed forms and in various biological fluids. In the last few years the possibility of analytical use of the lanthanide ions luminescence sensitization effect as well as their decrease/enhancement effects by some inorganic and organic anions, has been of special interest (8). In this paper we have utilized the enhancement effect of sensitized luminescence by citrate ions for the determination of MC, which is not an Ln luminescence sensitizer. Mosapride citrate (MC) The aim of this study was to develop a simple, rapid, precise and sensitive method for the determination of MC in pharmaceutical formulations without the need of extraction or heating. This method is based on the europium complex with the ligand -9-fluoro-1-hydroxy-5-methyl-3-oxo-6,7-dihydro-3H,5H-pyrido[3,2,1-ij]quinoline-2-carboxylic acid (2-piperazin-1-yl-ethyl)-amide as a luminescence probe. EXPERIMENTAL Apparatus Luminescence and excitation spectra and lifetimes were measured with a Solar luminescence spectrometer (Belorussia) and an Aminco-Bowman Series 2 (SLMñAminco, Rochester, New York) spectrometer with a 150-W xenon lamp. Abstract: New europium complexes of 3-oxo-1-hydroxy-quinoline-2-carboxylic acid amide derivatives (L 1 -L 3 ), which are highly luminescent and do not require luminescence enhancers are reported. The luminescence intensity of the Eu-L 1 -3 complexes was enhanced by the addition of citrate ions in water solution. A sensitive luminescence enhancement system was developed for the determination of citrate ions on the base of Eu-9-fluoro-1-hydroxy-5-methyl-3-oxo-6,7-dihydro-3H,5H-pyrido[3,2,1-ij]quinoline-2-carboxylic acid (2-piperazin-1-yl-ethyl)-amide (L 1 ) complex. This effect was applied to the determination of the drug, which is not a lanthanide luminescence sensitizer. The EuñL 1 ñ Cit complex with a componentsí ratio 1:1:2 was proposed to be used as the analytical form for the luminescence determination of drug ñ mosapride citrate. The calibration curve is linear in the range of 1.0-25.0 µg/mL of mosapride citrate (LOD is 0.35 µg/mL). This method was applied for the determination of mosapride citrate in dosage form -tablets ìMosid MTî ñ 2.5 mg

Sensitive luminescent determination of DNA using the terbium(III)–difloxacin complex

The interaction of the terbium–difloxacin complex (Tb–DFX) with DNA has been examined by using UV–vis absorption and luminescence spectroscopy. The Tb–DFX complex shows an up to 85-fold enhancement of luminescence intensity upon titration with DNA. The long decay times allow additional detection schemes like time-resolved measurements in microplate readers to enhance sensitivity by off-gating short-lived background luminescence. Optimal conditions are found at equimolar concentrations of Tb3+ and DFX (0.1 or 1 μM) at pH 7.4. Under these conditions, the luminescence intensity is linearly dependent on the concentration of ds-DNAs and ss-DNA between 1–1500 ng mL−1 and 4.5–270 ng mL−1, respectively. The detection limit is 0.5 ng mL−1 for ds-DNAs and 2 ng mL−1 for ss-DNA. The mechanism for the luminescence enhancement was also studied