Simultaneous evaluation of losartan and amlodipine besylate using second-derivative synchronous spectrofluorimetric technique and liquid chromatography with time-programmed fluorimetric detection

This study is concerned with two sensitive, fast and reproducible approaches; namely, second-derivative synchronous fluorimetry (method I) and reversed phase high-performance liquid chromatography with fluorimetric detection (method II) for synchronized evaluation of losartan (LOS) and amlodipine besylate (AML). Method I is based on measuring second-derivative synchronous fluorescence spectra of LOS and AML at Δ λ = 80 nm in water. The experimental factors influencing the synchronous fluorescence of the considered compounds were sensibly adjusted. The chromatographic analysis was executed on a Nucleodur MN-C18 column of dimensions; 250 × 4.6 mm i.d. and 5 µm particle size). The fluorimetric detection was time-programmed at λ em = 440 nm for AML (0.0–7.5 min) and at λ em = 400 nm for LOS (7.5–10 min) after excitation at λ ex = 245 nm. The mobile phase is a blend of acetonitrile with 0.02 M phosphate buffer in a proportion of 45 : 55, pH 4.0, pumped using a flow rate of 1 ml min −1 . The calibration plots were established to be 0.1–4.0 µg ml −1 for both drugs in method I and 0.05–4.0 µg ml −1 for both drugs in method II. The study was extended to the evaluation of the two drugs in their co-formulated tablets.

Rapid and selective determination of pitavastatin calcium in presence of its degradation products and co-formulated drug by first-derivative micelle-enhanced and synchronous fluorimetric methods

New, selective and rapid methods are presented for determination of PIT in the presence of its hydrolytic degradation products and co-formulated drug, EZE. These methods are derivative micelle enhanced native fluorescence and synchronous fluorimetry.

Quick Multicomponent Analysis Based on Matrix Isopotential Synchronous Fluorimetry

Fast and precise methods are important in chemical and physical analysis, but determination of concentration of selected components in mixtures may have special difficulties. Excitation-emission matrices (EEM) are widely used in characterizing fluorescence emission. Based on these primary data, we present an improvement of matrix isopotential synchronous fluorimetry (MISF) and a method which ensures a very fast multicomponent analysis. MISF is generally combined with derivative technique (DMISF) to be able to eliminate the contribution of the background emission. Unfortunately, it is too sensitive to noises and fluctuations; thus the concentration region where it can be used, was limited until now. Our first aim was to reduce the influence of measurement errors and to increase the sensitivity of known MISF method by more than one order of magnitude. As a further result, using improved MISF, we got a method which ensures very fast determination of the wanted compound's concentration both in presence of one- or even two-component background of unknown concentration.