Kinetic spectrophotometric determination of gemifloxacin mesylate and moxifloxacin hydrochloride in pharmaceutical preparations using 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole

Simple,sensitive,and accurate kinetic spectrophotometric method was proposed for the determination of gemifloxacin mesylate (gmf) and moxifloxacin hydrochloride (mox) in pure forms and pharmaceutical preparations (tablets). the method is based on coupling the studied drugs with 4-chloro-7-nitrobenzo-2-oxa- 1,3-diazole (nbd-cl) in the presence of alkaline borate buffer. spectrophotometric measurement was achieved by recording the absorbance at 466 and 464 nm for gmf and mox,respectively,after a fixed time of 20 and 15 min on a water bath adjusted at 70 ± 5°c for both drugs. the different experimental parameters affecting the development and stability of the color were carefully studied and optimized. the absorbance-concentration plots were linear over the ranges 0.5-8.0 and 2.0-12 μg ml-1 for gmf and mox,respectively. the limit of detection of the kinetic method was about 0.12 (2.47 × 10-7 m) and 0.36 (8.22 × 10-7 m) μg ml-1 for gmf and mox,respectively. the proposed methods have been applied and validated successfully with percentage relative standard deviation (rsd% ≤ 0.52) as precision and percentage relative error (re% ≤ 1.33) as accuracy. the robustness of the proposed method was examined with recovery values that were 97.5-100.5 ± 1.3-1.9%. statistical comparison of the results with the reference spectrophotometric methods shows excellent agreement and indicates no significant difference in accuracy or precision. © 2014 mohammed g. abdel wahed et al.