Determination of ofloxacin and norfloxacin by ferrous complexing spectrophotometric method

The room temperature complexing reactions of ofloxacin and norfloxacin with Fe(III)were studied.It was found that,in acidic medium,ofloxacin and norfloxacin react with Fe(III)to form orange-yellow complexes with the maximum absorption at a wavelength of 436nm.When the concentration of ofloxacin and norfloxacin is in the range of 2.24-192mg/L and 8.0-248mg/L,it is linearly proportional to the absorbancy of the solutions,and relevant linear regression equations are expressed as A = 0.009 06+0.005 7 c(c,mg/L;r = 0.999 3;ofloxacin)and A =0.001 23+0.003 04 c(c,mg/L;r=0.999 8;norfloxacin).The detection limits for ofloxacin and norfloxacin are 0.41and 0.76mg/L,respectively.A total of 11repeat measurements for ofloxacin and norfloxacin with the same concentartion of 64.0mg/L reveal that the relative standard deviations are 0.6%and 0.8%,respectively.As-established method was adopted to determine the contents of the major components in ofloxacin and norfloxacin drugs,and it was found that the recoveries are in the range of 99.7%-104.7%.