Isotachophoretic analysis of pharmaceutic formulations with different matrices: Determination of nicotinic acid in capsules, tablets, dragees, ointments and tinctures

Chromatographic and capillary electrophoretic methods for the analysis of nicotinic acid and its metabolites

Methods for the assay of nicotinic acid (NiAc) and its metabolites in biological fluids using high-performance liquid chromatography (HPLC) and capillary electrophoresis (CE) are reviewed. Most of the references cited in this review concern HPLC methods. A few CE methods that have been recently reported are also included. As these compounds are relatively polar and have a wide range of physico-chemical properties, the sample pre-treatment or clean-up process prior to analysis is included. Most HPLC methods using an isocratic elution system allow determination of a single or few metabolites, but gradient HPLC methods enable simultaneous determination of five to eight compounds. Simultaneous determination of NiAc including many metabolites in a single run can be achieved by CE. We also discuss the pharmacokinetics of NiAc and some of its metabolites.

Concept of response factor in capillary isotachophoresis. Determination of drugs in solution for intravenous injection

Twenty-six drugs in solutions for intravenous injection were determined by capillary isotachophoresis with only one calibration point for each component. The maximum deviation of the labelled concentration was 2%. A new calibration constant is introduced, viz., the response factor (RF, dimensionless), which is independent of the diameter of the capillary, the construction of the universal detector and the driving current used during detection. It is shown that the RF can be used on different equipment, using different currents during detection. It appears that the RF is usable for routine analysis when a deviation of 5% is acceptable. Daily one-point recalibration, however, improves this value to 1%.

Host-guest complexation in capillary isotachophoresis. II. Determination of aminophenol and diaminobenzene isomers in permanent hair colorants by using capillary isotachophoresis

The separation of 2-, 3- and 4-aminophenol and 1,2-, 1,3- and 1,4-diaminobenzene is studied by using capillary isotachophoresis. In order to obtain complete resolution of the six cations beta-cyclodextrin was used. The analytical method was used for the determination of aminophenol and diaminobenzene isomers in permanent hair colorant creams.