Precision study on capillary electrophoresis methods for metacycline.

A CE method for metacycline (MTC) determination was investigated in an inter-laboratory experiment. Many problems were encountered in this study, most of which were related to the transfer of the method to different CE equipment. The reported problems could be classified into different categories: problems related to the precision, to the parameters in the protocol, and to the MTC peak shape.

Interlaboratory study of a NACE method for the determination of R-timolol content in S-timolol maleate: assessment of uncertainty.

Analyses of statistical variance were applied to evaluate the precision and practicality of a CD-based NACE assay for R-timolol after enantiomeric separation of R- and S-timolol. Data were collected in an interlaboratory study by 11 participating laboratories located in Europe and North America. General qualitative method performance was examined using suitability descriptors (i.

Capillary electrophoresis-mass spectrometry in impurity profiling of pharmaceutical products.

Generally reversed-phase high-performance liquid chromatography (RP-HPLC) methods are extensively applied during quality control of pharmaceutical products. Since capillary electrophoresis (CE) is based on a different separation principle and consequently results in a unique selectivity compared to RP-HPLC, it can advantageously be used as an orthogonal technique. CE equipped with a mass spectrometer detector provides even more information that can be helpful for identification and structural elucidation purposes.

Optimization of enantiomeric separations in capillary electrophoresis by applying a design of experiments approach.

During early-phase pharmaceutical development, it is important to find an initial separation of enantiomeric compounds quickly in order to determine the enantiomeric purity of chiral drug substances. Highly selective screening methods are necessary to analyze the products to discover a satisfactory separation of the enantiomeric compounds. A screening approach based on the use of mixtures of multiple cyclodextrins in chiral capillary electrophoresis was employed to find the initial separation of chiral compounds.

Fast method development and rapid analysis using a screening approach for enantiomeric separations in capillary electrophoresis.

In order to speed up the trial-and-error process during enantioselective capillary electrophoresis methods development, a systemized approach is proposed to develop methods by applying several screening methods in the search for an initial separation. Screening methods combine high selectivity with broad applicability and are applied to find an initial enantiomeric separation during early pharmaceutical development (pre-Phase 1 to Phase 1). The goal is to achieve enantiomeric separation rapidly in order to characterize the chiral purity of pharmaceutical products.

Optimization and validation of an enantioselective method for a chiral drug with eight stereo-isomers in capillary electrophoresis.

Highly selective capillary electrophoresis (CE) screening methods were applied to find a satisfactory separation of a chiral drug with eight stereoisomeric compounds. The initial separation conditions were further optimized using response surface modelling by applying a Box-Behnken experimental design. This approach resulted in a rapid and efficient optimization of the buffer concentration, the concentration of two cyclodextrins, and the run voltage, in order to obtain final separation conditions of the method.

A screening strategy for the development of enantiomeric separation methods in capillary electrophoresis.

Method development of enantiomeric separations in capillary electrophoresis (CE) is a time-consuming task, since finding the appropriate chiral selector is usually a "trial and error" process. It is impossible to predict the selectivity of a selector towards a certain enantiomer. Therefore, the affinity of all selectors has to be examined one at a time.

Capillary electrophoresis as an orthogonal technique in HPLC method validation.

High-performance liquid chromatography is usually used to assay the main compound and organic impurity content of drug substance and drug product during pharmaceutical development. A crucial validation parameter of these methods is specificity--the ability to unequivocally assess the analyte in the presence of component expected to be present. Typically, these include impurities, degradation products, and matrices.