Micellar liquid chromatographic determination of five antianginals in pharmaceuticals

Quantification of tamoxifen in pharmaceutical formulations using micellar liquid chromatography

This paper describes a micellar liquid chromatographic method used to analyze tamoxifen (TAMO) in pharmaceutical formulations, while focusing in its interesting features. Solid samples were solved in a micellar solution, irradiated at 254 nm, filtered and injected. Extraction steps were avoided and thus expediting the procedure. Tamoxifen was resolved in <5 min, using a mobile phase containing 0.15 M sodium dodecyl sulfate-7% pentanol at pH 3, running at 1.5 mL/min under an isocratic mode at 40°C through a C18 column. Detection was achieved by fluorescence by excitation at 260 nm and emission at 380 nm. The validation was performed following the requirements of the International Conference on Harmonization (ICH) Tripartite Guidelines in terms of: specificity, sensitivity, calibration range (0.2 - 20 mg/L), accuracy (98.8 - 101.7%), precision (<1.5%) and robustness (<6.2%). The method was applied to quantify TAMO in TAMO citrate tablets supplied in Spain, and was found appropriate for the quality control of TAMO formulations.

Validation of micellar LC-based methods applied to analyze foodstuffs

The validation of several micellar LC-based analytical methodologies was described. These methods were able to quantify quinolones in fish from fisheries, hydroxytyrosol in olive extracts and biogenic amines in anchovy sauce. The validation was performed following the requirements of official guides to provide more reliability. Two guides suggested by renowned institution are described: US FDA Guidance for Industry and EU Regulation 2002/657/EC Decision. The appropriate guide was used for each method, depending of the analyte, the matrix and the scope of sample. The calculated validation parameters were those proposed by the guide: selectivity, calibration range, linearity, LOD and LOQ, inter- and intra-day accuracy and precision, limit of decision, detection capability, robustness, recovery and stability. The methodologies were successfully validated by the selected guideline, indicating their suitability to be applied to analysis of real samples, proven to be useful to its intended purpose.

Recent theoretical and practical applications of micellar liquid chromatography (MLC) in pharmaceutical and biomedical analysis

Micellar liquid chromatography (MLC) is an analytical technique belonging to the wide range of reversed-phase liquid chromatographic (RP-LC) separation techniques. MLC with the use of surfactant solutions above its critical micellar concentration (CMC) and the addition of organic modifiers is currently an important analytical tool with still growing theoretical considerations and practical applications in pharmaceutical analysis of drugs and other biologically active compounds. The use of MLC as an alternative, relatively much faster in comparison to conventional chromatographic separation techniques has several advantages, especially as being suitable for screening pharmaceutical analysis. The analytical data received from MLC analysis are considered a useful source of information to predict passive drug absorption, drug transport and other pharmacokinetics and physicochemical measures of pharmaceutical substances. In the review several MLC assays for determination of drugs and other active compounds in biological samples were compared and critically discussed. The presented overview provides information on recent applications and achievements connected with the practical use of MLC. The review covers fields of interest related to theory and mechanism of MLC separation, direct applications of MLC in pharmaceutical analysis, including optimization and efficiency of separation with the use of modification of stationary phase and mobile phase compositions as well as the determination of physicochemical characteristics of drugs by MLC.

Determination of diltiazem based on the reduction of Cu(II)–BCA complexes in micellar medium

A simple method was developed for determining microquantities of diltiazem, based on the reduction of copper(II) in buffered solution (pH 7.0) and the use of a micellar medium containing 4,4′-dicarboxy-2,2′-biquinoline acid. The copper(I) produced reacts with 4,4′-dicarboxy-2,2′-biquinoline acid and the complexes formed are spectrophotometrically measured at 558 nm. A typical calibration graph shows good linearity (r = 0.993) from 20 to 100 μg mL–1 of diltiazem. The limit of detection and relative standard deviation were calculated as 12 μg mL–1 (99% confidence level) and 3.5% (40 μg mL–1; n = 6), respectively, with a mean recovery value of 96.5% found in pharmaceutical dosages. A straightforward and effective way to recycle the reagents is addressed. The hazardous aspects of the Cu(I)–BCA reaction are presented as well.