Electrochemical determination of azithromycin in pharmaceutical formulations by flow injection analysis.

PATRICIA INES ORTIZ; PALOMEQUE, M. E.

Porto, Portugal

Congreso; X International Conference on Flow Analysis.; 2006

Azithromycin (AZ) is a novel macrolide antibiotic and a semi synthetic acid-stable erythromycin derivative. It is used against respiratory tract and skin infections and sexually transmitted diseases. It has been determined in biological fluids by several methods [1-3]. However, few methods for its determination in pharmaceutical formulations were described in the literature such as: chromatography with electrochemical detection [4], fluorimetry with a previous drug derivatization [5], square-wave voltammetry [6] and cyclic voltammetry [7]. The US Pharmacopoeia [8] describes a chromatographic method that needs the use of a specific “Gamma-alumina” column which is expensive and difficult to obtain commercially. An amperometric FIA system is proposed for azithromycin determination in different standard solutions and commercial presentations.             The study was performed electrochemically using cyclic voltammetry, where an oxidation peak at 0.70 V was obtained (vs. Ag/AgCl/1 M NaCl), during the negative scan no reduction peaks were obtained indicating that the process is irreversible. A FIA – amperometric method for azithromycin determination was also developed. A working glassy carbon electrode and a Ag/AgCl/NaCl (3 M) reference electrode were used. The determination is based on the electrochemical oxidation of the azithromycin at 0.9V in Britton Robinson buffer solution (pH=8). Due to the adsorption of the reaction products on the electrode surface, an effective cleaner cycle was implemented. By using the optimum chemical and FIA conditions, a concentration linear range of 1.0 to 10.0 mg L-1 and a detection limit (LOD) of 0.76 mg L-1 are obtained. The method was validated and satisfactorily applied to the determination of azithromycin in pharmaceutical formulations. [1]  G. Bahrami, S. Mirzaeei, A. Kiani. J. Chromatogr. B, 820 (2005), 277. [2]  R.V.S. Nirogi, V.N. Kandikere, M. Shukla, K. Mudigonda, S. Maurya, R. Boosi, A. Yerramilli Anal. Chim. Acta, 53 (2005), 1. [3]  E. Wilms, H. Trumpie, W. Veenendaal, D. Tour. J. Chromatogr. B, 814 (2005), 37. [4]  R. Gandhi, C.L. Kaul, R. Panchagnula, J. Pharm. Biomed. Anal. 23 (2000) 1073. [5]  P.Y. Kashaba, J. Pharm. Biomed. Anal. 27 (2002) 923. [6]  O.A.El-M. Farghaly, N.A.L. Mohamed, Talanta 62 (2004) 531. [7]  B. Nigovic, B. Simunic. J. Pharm. Biomed. Anal, 32 (2003) 197. [8]  United States Pharmacopoeia. National Formulary, USP23/NF18, USP Convention Inc. Rockville, MD, 1995, pp. 152.