Electrochemical study of hydrochlorothiazide and its determination in urine and tablets

A voltammetric study of hydrochlorothiazide (HCTZ) at glassy carbon electrode was carried out. The drug in Britton-Robinson buffer (pH 3.3) is oxidized at + 1040 mV, giving rise to a well-defined peak. Cyclic voltammetric study indicates that the oxidation process is irreversible and diffusion-controlled. A sensitive, simple and tune-saving differential pulse anodic voltammetric procedure has been developed. The procedure has been applied for the drug determination in human urine with no prior extraction and in commercial tablets. The proposed method has been validated. The limit of detection for the standard solution was 5.0 ng ml(-1) and for the drug in urine was 14.0 ng ml(-1). The results obtained from the analysis of commercial tablets were compared statistically with those obtained from the USP 26 high-performance liquid chromatographic (HPLC) method. (C) 2003 Elsevier B.V. All rights reserved.