Comparative validations of non-aqueous capillary electrophoresis and high-performance liquid chromatography methods for the simultaneous determination of histamine H2 receptor antagonists in human urine

This paper reports a previously optimised method based on non-aqueous capillary electrophoresis (NACE) using UV detection for the separation and simultaneous determination of cimetidine (CIM), ranitidine (RAN), roxatidine (ROX), nizatidine (NIZ) and famotidine (FAM) in human urine. Separation is performed at 25 °C and at a separation voltage of 15 kV. Methanol containing 10 mM ammonium acetate and 0.2% acetic acid was used as background electrolyte, and detection at 214 nm. These conditions allow the five analytes to be separated within 4 min. In addition in the present paper a HPLC method using diode-array as well as detector, was proposed as standard analytical method, which chromatography conditions were following: a mobile phase consisting of 80:20 20 mM phosphate buffer (pH 7.5)/acetonitrile, and using 1 mL min−1 as flow rate of the mobile phase. Detection limits were evaluated on the basis of baseline noise and were establishing between 8 and 15 μg L−1 for NACE and between 16 and 162 μg L−1 for HPLC. The methods showed good precision with overall intra- and inter-day variations of 0.5–2.0% and 0.7–3.8%, respectively. Finally the proposed methods were successfully applied to the screening determination of the analytes in human urine, with recoveries between 97 and 105%, being able the use as pharmacokinetic data in clinical urine samples.