Comprehensive Review on Chiral Stationary Phases in Single-Column Simultaneous Chiral-Achiral HPLC Separation Methods.

This comprehensive review explores the utilization of chiral stationary phases (CSPs) in the context of single-column simultaneous chiral-achiral high-performance liquid chromatography (HPLC) separation methods. While CSPs have traditionally been pivotal for enantioselective drug analysis, contemporary CSPs often exhibit notable chemoselective properties. Consequently, there is a discernible trend towards the development of methodologies that enable simultaneous enantio- and chemoselective separations utilizing a single CSP-based chromatographic column. This review provides an exhaustive overview of reported HPLC methods in this domain, with a focus on four major CSP types: cyclodextrin-, glycopeptide antibiotic-, protein-, and polysaccharide-based CSPs. This article delves into the diverse applications of CSPs, encompassing various chromatographic modes such as normal phase (NP), reverse phase (RP), and polar organic (PO). This review critically discusses method development, emphasizing the additional chemoselective separation mechanisms of CSPs. It also explores possibilities for method optimization and development, concluding with future perspectives on this evolving field. Despite the inherent challenges in understanding the retention mechanisms involved in chemoselective separations, this review highlights promising trends and anticipates a growing number of simultaneous enantio- and chemoselective methods in pharmaceutical analyses, pharmacokinetic studies, and environmental sample determinations.

Development of a generic method for the determination of proton-pump inhibitors by capillary zoneelectrophoresis

A generic capillary zone electrophoresis method was developed for the analysis of four proton pump inhibitors: omeprazole, pantoprazole, lansoprazole and rabeprazole. During preliminary analysis screening of phosphate buffers at different pH levels was performed, in order to determine the optimum pH domain suitable for the simultaneous determination of all studied compounds. A face centered central composite design was employed for the optimization of separation conditions. The effect of buffer concentration, pH and applied voltage was studied; resolution between peaks and migration time of the last compound were considered as responses. Other factors as system temperature, injection parameters, capillary length, were held constant during the optimization process. The optimized conditions consisted of 40mM phosphate background electrolyte at pH 5.0, +25 kV applied voltage and 20 °C temperature. The migration order of the analytes was as follows: rabeprazole, omeprazole, lansoprazole and pantoprazole. Full resolution of all analytes was achieved within 9 minutes. The method was validated and proved to be suitable in terms of repeatability, sensitivity, linearity, accuracy and robustness. Determinations from commercially available pharmaceutical formulation were performed for omeprazole; good reproducibility and recovery were obtained.

Simultaneous determination of loratadine, desloratadine and cetirizine by capillary zone electrophoresis.

PURPOSE: The aim of the study was the development of a simple and rapid analytical procedure for the determination of the most frequently used antihistamine derivatives. METHODS: A capillary zone electrophoretic method was developed for the simultaneous separation of loratadine, desloratadine and cetirizine. Efforts were focused primarly on the optimisation of the experimental parameters: buffer composition and concentration, buffer pH, applied voltage, temperature, injection pressure and time. RESULTS: The optimised parameters for the separation were: 25 mM buffer electrolyte, buffer pH 2.5, voltage + 25 kV, temperature 25 °C, injection pressure 50 mbar, injection time 3 seconds, capillary 48 cm (effective length 40 cm) x 50 µm, detection at 240 nm. Under these conditions, the analysis time was below 5 minutes, the order of migration being: desloratadine, cetirizine and loratadine. The developed method was validated in terms of linearity, limits of detection and quantification, intra- and inter-day precision, selectivity and robustness. CONCLUSION: Capillary zone electrophoresis proved to be a suitable method for the simulatneous determination of the three studied antihistamine derivatives.

Principles of micellar electrokinetic capillary chromatography applied in pharmaceutical analysis.

Since its introduction capillary electrophoresis has shown great potential in areas where electrophoretic techniques have rarely been used before, including here the analysis of pharmaceutical substances. The large majority of pharmaceutical substances are neutral from electrophoretic point of view, consequently separations by the classic capillary zone electrophoresis; where separation is based on the differences between the own electrophoretic mobilities of the analytes; are hard to achieve. Micellar electrokinetic capillary chromatography, a hybrid method that combines chromatographic and electrophoretic separation principles, extends the applicability of capillary electrophoretic methods to neutral analytes. In micellar electrokinetic capillary chromatography, surfactants are added to the buffer solution in concentration above their critical micellar concentrations, consequently micelles are formed; micelles that undergo electrophoretic migration like any other charged particle. The separation is based on the differential partitioning of an analyte between the two-phase system: the mobile aqueous phase and micellar pseudostationary phase. The present paper aims to summarize the basic aspects regarding separation principles and practical applications of micellar electrokinetic capillary chromatography, with particular attention to those relevant in pharmaceutical analysis.

Thin layer chromatographic analysis of Beta-lactam antibiotics.

PURPOSE: The paper describes some thin layer chromatographic procedures that allow simple and rapid separation and identification of penicillins and cephalosporins from complex mixtures. METHODS: Using silicagel GF254 as stationary phase and selecting different mobile phases we succeeded in the separation of the studied beta-lactamins. Our aim was not only to develop a simple, rapid and efficient method for their separation but also the optimization of the analytical conditions. RESULTS: No system will separate all the beta-lactams, but they could be identified when supplementary information is used from color reactions and/or by using additional chromatographic systems. CONCLUSIONS: The right combination of solvent system and detection method allows the identification of the studied penicillins and cephalosporins and can be successfully used in the preliminary analysis beta-lactam antibiotics. CONCLUSION: The right combination of solvent system and detection method allows the identification of the studied penicillins and cephalosporins and can be successfully used in the preliminary analysis beta-lactam antibiotics.

[Stability of some medicinal solutions with captopril]. / Stabilitatea unor soluti orale de captopril.

UNLABELLED: The aim of the study was to investigate the stability of some oral liquid formulations containing 1 mg/ml captopril. MATERIAL AND METHOD: The oral solutions were prepared using captopril substance, keeping the formulation as simple as possible to avoid potentially undesirable excipients. Samples were stored for 39 days below 8 degrees C and at 22 +/- 3 degrees C and analysed for physical, chemical and microbiological stability. RESULTS: The formulations with ascorbic acid are stable for seven days either at 8 and 22 degrees C and could be prepared in hospital pharmacy as a more safely alternative to children terapy with tablets powders.