Recent advances in applications of capillary electrophoresis with Fourier transform convolution: application to kinetic study of hydrolysis of hydrochlorothiazide

Abstract

This manuscript discusses the application of chemometrics to the handling of capillary electrophoresis (CE) response data using the internal standard method. Derivative treatment (D method) of CE response data was used. Furthermore, convolution of the resulting derivative curves using discrete Fourier functions, the so-called D/FF method, was applied. This approach is extremely beneficial where ideal baseline separation of electrophoretic peaks cannot be achieved, as in the case of drug isomers, structural related impurities or degradation products. The potential of these methods for resolving overlapping peaks was evaluated using the hydrolysis of hydrochlorothiazide (HCT) as an illustrative model. CE analysis was performed using a deactivated fused silica capillary (55 cm effective length and 75 μm i.d.), and background electrolyte solution consisted of phosphate buffer (20 mM, pH 8.0). Both chemometric methods allowed the determination of the intact drug (HCT) and its degraded form with high a degree of accuracy and precision. This was found to be beneficial in studying the degradation kinetics of hydrolysis of HCT at different temperatures. The corresponding pseudo-first order rate constants and half-lives were calculated. Finally, the proposed method made use of diode array detection as a tool for peak identity and purity confirmation.

Analytical methods for kinetic studies of biological interactions: A review

“…One way CE can be used for kinetic measurements is to study interactions that have long reaction times (e.g., hours) and small dissociation rate constants (i.e., k −1 values in the range of 10 −3 to 10 −6 s −1 ) [151–157]. To investigate this type of reaction, the target and binding agent can be mixed prior to their injection onto the CE system.…”

Recent advances in capillary electrophoretic migration techniques for pharmaceutical analysis (2013–2015)

“…Recent publications on the analysis of related substances in pharmaceutical drugs have been compiled in Table . Most separations were carried out in the CZE mode, while four methods applied MEKC and one MEEKC conditions .…”

“…While most publications dealt with organic impurities, two studies investigated inorganic analytes. Gotti and coworkers reported a method for the determination of free iron(II) in an iron‐sucrose product used for the treatment of anemia . The injection is a colloidal solution of ferric hydroxide in complex with sucrose containing 20 mg/mL elemental iron.…”

“…Sample (a) contained about 5 % iron(II), sample (b) about 10 % iron(II); IS, internal standard (suprofen). (Reproduced with permission from Wiley‐VCH from . )…”

Capillary Electrophoresis for Quantitative Studies of Biomolecular Interactions

“…The validation parameters usually are determined and presented together with other experimental results or in separated chapter. 86,95,96 Selectivity (specificity) is the ability to measure accurately and specifically the analyte of interest in the presence of other components that may be contained in the sample. Specificity refers to methods, which produce a response for a single analyte, whereas selectivity refers to methods that produce responses for a number of chemical entities, which may or may not be distinguished.…”