Voltammetric Determination of Azidothymidine Using Silver Solid Amalgam Electrodes

Abstract

A new simple and direct electroanalytical method was developed for the determination of azidothymidine in commercial pharmaceutical preparations. It is based on differential pulse voltammetry at silver solid amalgam electrode with polished surface (p-AgSAE) or surface modified by mercury meniscus (m-AgSAE). The electroreduction of azidothymidine in basic media at these electrodes gives rise to one irreversible cathodic peak. Its potential in 0.05 mol L À1 borate buffer, pH 9.3 at ca. À 1050 mV is comparable to that using hanging mercury drop electrode (HMDE). Achieved limits of quantitation are in the 10 À7 mol L À1 concentration range for both amalgam electrodes. According to the procedure based on the standard addition technique, the recoveries of known amounts of azidothymidine contained in pharmaceutical preparations available in capsules were 101.4 AE 1.8% (m-AgSAE), 100.3 AE 3.5% (p-AgSAE) and 102.0 AE 1.0% (HMDE) (n ¼ 10). There was no significant difference between the values gained by proposed voltammetric methods and the HPLC-UV recommended by the United States Pharmacopoeia regarding the mean values and standard deviations.

Determination of the Antiretroviral Drug Zidovudine in Diluted Alkaline Electrolyte by Adsorptive Stripping Voltammetry at the Mercury Film Electrode

“…Several methods have been discovered for the quantitative determination of zidovudine including chromatog- raphy [9][10][11][12][13][14][15], fluorescence polarization immunoassay [16], using diamond paste based immunosensor [17], fluorescence spectroscopy [18] and voltammetry [19][20][21][22][23][24].…”

Voltammetric and amperometric determination of N-nitroso antineoplastic drugs at mercury and amalgam electrodes

“…For the pH range 2.0-6.0, the E p shift can be described by the equation (for DCV) E p (V) = -0.052 pH -0.819 (R = -0.9744). Such potential difference for HMDE and m-AgSAE is sporadic, typical differences for other organic compounds were 0-100 mV (refs [44][45][46] versibility of the electroreduction of BCNU at both electrodes; the observed linear dependences of peak currents on the square root of the scan rate confirm its diffusion control. A more detailed explanation of the differences of electrochemical behaviour of BCNU at HMDE and m-AgSAE would require a more extentive mechanistic study.…”

“…The obtained parameters and L Q s mostly in the 10 -6 mol l -1 concentration range are summarized in Table II. A lower sensitivity by an order of magnitude and higher L Q s were obtained for BCNU using DPV at m-AgSAE in comparison with HMDE; this was frequently reported also for other organic compounds [44][45][46] . An excellent repeatability of 1.37% (s r ) was obtained for the lowest attainable concentration of BCNU (4 × 10 -6 mol l -1 ), which resulted in L Q in the 10 -7 mol l -1 concentration range.…”

Comparison of Mercury Vapor Pressure of Silver Amalgam-Based Electrode Materials Using AAS

“…earlier used in our laboratory Barek, Peckova, and Vyskocil 2008;Barek et al 2009;Cabalkova et al 2009;Danhel, Barek, and Yosypchuk 2009;Niaz et al 2009a;Peckova et al 2009;Yosypchuk and Barek 2009). Several types of amalgam electrodes have been developed and used for analysis of a variety of organic and inorganic substances.…”