Journal of Pharmaceutical and Biomedical Analysis 34 (2004) 509–516 Adsorptive stripping voltammetric behaviour of azomethine group in pyrimidine-containing drugs Suzy M. Sabry ∗ , Magda H. Barary, Mohamed H. Abdel-Hay, Tarek S. Belal Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, University of Alexandria, Alexandria, Egypt Received 30 September 2003; accepted 18 October 2003 Abstract The stripping voltammetric behaviour of buspirone hydrochloride (BUS) and piribedil (PIR), as models of pyrimidine-contai- ning compounds, was studied using a hanging mercury drop electrode (HMDE). A sensitive adsorptive stripping voltammetric method for determination of such drugs is described. The voltammetric peaks were obtained at -1.23 and -1.22 V for BUS and PIR, respectively, which correspond to the reduction of the azomethine group of pyrimidine ring in Britton–Robinson buffer (pH 7). Factors such as pH of supporting electrolyte, accumulation potential and time and instrumental parameters were optimized. Calibration plots and regression data validation, accuracy, precision, limits of detection, limits of quantification, and other aspects of analytical merit are presented. The applicability of the method was evaluated through determination of BUS and PIR in tablet dosage forms. A preliminary study of the analysis of plasma samples, spiked with the investigated drug, after a simple extraction procedure is described. © 2003 Elsevier B.V. All rights reserved. Keywords: Azomethine group; Pyrimidine-containing drug; Britton–Robinson buffer; Adsorptive stripping voltammetry 1. Introduction Buspirone hydrochloride (8-[4-(4-pyrimidin-2-ylp- iperazin-1-yl)butyl]-8-azaspiro[4,5]decane-7,9-dione hydrochloride, BUS) is an anxiolytic drug. It has dop- aminergic, noradrenergic, and serotonin-modulating properties and its anxiolytic effects appear to be re- lated to its action on serotonin neurotransmission [1]. ∗ Corresponding author. Tel.: +20-3-4833810; fax: +20-3-4873273. E-mail address: suzymsabry@hotmail.com (S.M. Sabry). The USP 24 specifies a HPLC method for the assay of BUS bulk drug and tablets [2]. The drug is not offi- cial in BP. Several chromatographic studies concerned with the quantification of BUS or BUS simultaneously with its metabolite, 1-(2-pyrimidinyl)piperazine in hu- man plasma have been reported [3–10]. Spectropho- tometric methods based on color reactions have been used for the assay of BUS in tablets [11,12]. Squella et al. [13] investigated the polarographic behaviour of BUS at the dropping mercury elec- trode and developed a differential pulse polarographic (DPP) method for determining the drug in tablets. The method is based on the reduction of the azomethine 0731-7085/$ – see front matter © 2003 Elsevier B.V. All rights reserved. doi:10.1016/S0731-7085(03)00631-9