Electrochemical determination of minocycline in pharmaceutical preparations

The possibility of electrochemical determination of minocycline on mercury and solid electrodes by various voltammetric and polarographic techniques has been undertaken. The influence of some chemical (ionic strength and pH) and instrumental parameters on the main reduction signal of minocycline was investigated. The alternating current polarographic (ACP) technique was applied to the minocycline determination either in pure form or in a commercial pharmaceutical preparation. The common excipients did not interfere. The antibiotic could be detected in the concentration range $1\ 10^{-3} - 5\ 10^{-6}$ mol L$^{-1}$. The detection limit for the quantitative determination by ACP was 1 10$^{-6}$ mol L$^{-1}$ minocycline in aqueous medium of 0.1 M NaCl. The mean recovery was 99.2% with a relative standard deviation (RSD) of 2.93% ($n = 8$)