TY - JOUR
T1 - Sequential injection technique employed for stoichiometric studies, optimization and quantitative determination of some fluoroquinolone antibiotics complexed with iron(III) in sulfuric acid media
AU - Suliman, Fakhr Eldin O.
AU - Sultan, Salah M.
PY - 1996
Y1 - 1996
N2 - A sequential injection spectrophotometric method for stoichiometric studies, optimization and quantitative determination of ciprofloxacin and norfloxacin was developed. The work is based on the complexation reaction of ciprofloxacin and norfloxacin with iron(III) in sulfuric acid media and a spectrophotometric measurement of absorbances of the corresponding complexes at 447 and 430 nm respectively. The stoichiometries and formation constants were determined. A 1:2 iron(III) to drug mole ratio was found to give the most predominant complexes for both drugs with 5.00×10 -3 M H2SO4 and at 0.20 M ionic strength utilizing Job's method and the molar ratio method. A numerical method was utilized for the calculation of the formation constants, the logarithms of which were found to be 7.756±0.121 and 7.839±0.056, for ciprofloxacin and norfloxacin respectively. A factorial design together with the all-model-search method was utilized for the optimization of the concentration and aspiration volume of iron(III) as these were the variables which most affected peak absorbance. Working dynamic ranges of 50-500 ppm and 50-400 ppm were obtained for ciprofloxacin and norfloxacin respectively. The method was found to be suitable for the determination of these compounds in pharmaceutical preparations.
AB - A sequential injection spectrophotometric method for stoichiometric studies, optimization and quantitative determination of ciprofloxacin and norfloxacin was developed. The work is based on the complexation reaction of ciprofloxacin and norfloxacin with iron(III) in sulfuric acid media and a spectrophotometric measurement of absorbances of the corresponding complexes at 447 and 430 nm respectively. The stoichiometries and formation constants were determined. A 1:2 iron(III) to drug mole ratio was found to give the most predominant complexes for both drugs with 5.00×10 -3 M H2SO4 and at 0.20 M ionic strength utilizing Job's method and the molar ratio method. A numerical method was utilized for the calculation of the formation constants, the logarithms of which were found to be 7.756±0.121 and 7.839±0.056, for ciprofloxacin and norfloxacin respectively. A factorial design together with the all-model-search method was utilized for the optimization of the concentration and aspiration volume of iron(III) as these were the variables which most affected peak absorbance. Working dynamic ranges of 50-500 ppm and 50-400 ppm were obtained for ciprofloxacin and norfloxacin respectively. The method was found to be suitable for the determination of these compounds in pharmaceutical preparations.
KW - Ciprofloxacin
KW - Complexation
KW - Norfloxacin
KW - Sequential injection spectrophotometry
UR - http://www.scopus.com/inward/record.url?scp=0030375012&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0030375012&partnerID=8YFLogxK
U2 - 10.1016/0039-9140(95)01771-2
DO - 10.1016/0039-9140(95)01771-2
M3 - Article
AN - SCOPUS:0030375012
SN - 0039-9140
VL - 43
SP - 559
EP - 568
JO - Talanta
JF - Talanta
IS - 4
ER -