title: Capillary electrophoresis procedure for the simultaneous analysis and stoichiometry determination of a drug and its counter-ion by using dual-opposite end injection and contactless conductivity detection: application to labetalol hydrochloride.
abstract: In this work, a capillary electrophoresis (CE) procedure was developed for the simultaneous determination of a pharmaceutical drug and its counter-ion, namely labetalol hydrochloride. For this purpose, an uncoated fused-silica capillary, a low conductivity background electrolyte (BGE) and a capacitively coupled contactless conductivity detector (C(4)D) were employed. This detection system is highly sensitive and enables detection of inorganic as well as organic ions unlike with direct UV detection. Moreover, to be able to simultaneously analyze the cationic drug (labetalol(+)) and its anionic counter-ion (Cl(-)) in the same electrophoretic run without the need of a coated capillary, a dual-opposite end injection was performed. In this technique, the sample is hydrodynamically injected into both ends of the capillary. This method is simple and easy to perform since the different injection steps are automated by the CE software. This novel CE-C(4)D procedure with dual-opposite end injection has been successfully validated and applied for the analysis of chloride content in an adrenergic antagonist (labetalol hydrochloride). Thus, the hereby developed method has been shown to enable fast (analysis time<10 min), precise (repeatability of migration times<0.7% and of corrected-peak areas < 3.3%; n=6) and rugged analyses for the simultaneous determination of a pharmaceutical drug and its counter-ion.
authors.affiliation: Institut de Chimie Organique et Analytique (ICOA), CNRS FR 2708, UMR 6005, Université d'Orléans, BP 6759, Orléans 45067 Cedex 2, France.
authors.forename: Reine
authors.initials: R
authors.lastname: Nehmé
authors.forename: Adrien
authors.initials: A
authors.lastname: Lascaux
authors.forename: Raphaël
authors.initials: R
authors.lastname: Delépée
authors.forename: Bérengère
authors.initials: B
authors.lastname: Claude
authors.forename: Philippe
authors.initials: P
authors.lastname: Morin
mesh_terms: D019075:Electrophoresis, Capillary; D017022:Flow Injection Analysis / Q000295:instrumentation / Q000379:methods; D007477:Ions / Q000032:analysis; D007741:Labetalol / Q000032:analysis*; D013237:Stereoisomerism
chemical_list: D007477:Ions; D007741:Labetalol