Spectrophotometric Determination of Ciprofloxacin Using Charge-Transfer Complexation Technique

A sensitive and precise spectrophotometric method is described. The method is based on a charge –transfer (C-T) complexation of ciprofloxacin with chloranilic acid. The C-T complex formed absorbed ultraviolet-visible (UV-VIS) light at 520 nm. The calibration curve generated by plotting absorbance against concentration obeyed Beer’s law within the range of 5.6 to 120 µg/ml. The regression equation using least square method was A = bc + a that is A = 12c, with a correlation coefficient of r=0.9997 at n=6. The apparent molar absorptivity and Sandall sensitivity were 852.27 L/mol/cm and 0.3886 µg/cm² respectively. The limit of detection (LOD) and the limit of qualification (LOQ) were determined as per the current International For Harmonisation (ICH) guideline and were found to be 2.50 µg/ml and 8.33 µg/ml respectively. The method was validated for accuracy and precision (%RSD and %RE) and, the results obtained which were ≤1.37 and ≤2.75 respectively, were successfully used to analyse ten brands of ciprofloxacin labelled samples A-J. The assay results were statistically compared with those obtained via student t-test and F-test at 95% Confidence level and no significant difference was found. The applicability and accuracy of the method was further ascertained by recovery study via standard addition method. Excellent recoveries within the range stated in the official compendia (95.0-105.0 %) were obtained.