Determination of lomefloxacin, an antibacterial drug, in pharmaceutical preparations based on its polarographic catalytic wave in the presence of 2-iodoacetamide.
In a 0.125 mol/L phosphate (pH 6.6)/2.5 x 10(-4) mol/L 2-iodoacetamide solution, lomefloxacin yields a response of a polarographic catalytic current. The second-order derivative peak current of the catalytic wave of lomefloxacin is proportional to its concentration in the range of 1.0 x 10(-8)-1.0 x 10(-6) mol/L (r = 0.998). The sensitivity of the catalytic wave is 25-times higher than that of the corresponding reduction wave for 5.0 x 10(-7) mol/L lomefloxacin. The proposed method was applied to the determination of lomefloxacin in pharmaceutical preparations. The polarographic reduction wave is ascribed to a one-electron reduction of the C=C bond of lomefloxacin zwitterion accompanied by an acid-base equilibrium. The catalytic wave should be caused by regeneration of the lomefloxacin molecule at electrode surface due to the one-electron reduction product being further oxidized by electroreductive intermediate products of 2-iodoacetamide.
Song
J F
JF
Institute of Analytical Science, Northwest University, Xi'an, P R China. songjunf@nwu.edu.cn
Shao
Y
Y
Guo
W
W
D000477:Alkylating Agents / Q000378:metabolism; D000890:Anti-Infective Agents / Q000032:analysis* / Q000378:metabolism; D002384:Catalysis; D024841:Fluoroquinolones; D007460:Iodoacetamide / Q000378:metabolism*; D004364:Pharmaceutical Preparations / Q000032:analysis* / Q000378:metabolism; D011048:Polarography / Q000379:methods; D015363:Quinolones / Q000032:analysis* / Q000378:metabolism
D000477:Alkylating Agents; D000890:Anti-Infective Agents; D024841:Fluoroquinolones; D004364:Pharmaceutical Preparations; D015363:Quinolones; C053091:lomefloxacin; D007460:Iodoacetamide