Kinetic spectrophotometric determination of some fluoroquinolone antibiotics in bulk and pharmaceutical preparations

S Abou Taleb,R El Sheikh,A.A Gouda,M.G Abdel Wahed

doi:10.4314/bcse.v27i3.2

Abstract

A simple and sensitive kinetic spectrophotometric method was developed for the determination of some fluoroquinolonea antibiotics; gemifloxacin mesylate, moxifloxacin hydrochloride and gatifloxacin in bulk and in pharmaceutical preparations. The method is based upon a kinetic investigation of the oxidation reaction of the drugs with alkaline potassium permanganate at room temperature for a fixed time of 20 min for gemifloxacin and 15 min for moxifloxacin or gatifloxacin. The absorbance of the coloured manganate ion was measured at 610 nm. The absorbance–concentration plots were rectilinear over the ranges of 2.0-20, 4.0-24 and 4.0-40 µg mL−1 for gemifloxacin, moxifloxacin and gatifloxacin, respectively. The concentrations of the studied drugs were calculated using the corresponding calibration equations for the fixed-time method. The determination of the studied drugs by the fixed concentration and rate constant methods was also feasible with the calibration equations obtained but the fixed time method has been found to be more applicable. The different experimental parameters affecting the development and stability of the colors were carefully studied and optimized. The proposed method was applied to the determination of the studied drugs in pharmaceutical formulations. KEY WORDS: Kinetic determination, Spectrophotometry, Fluoroquinolone antibiotics, Potassium permanganate, Pharmaceutical preparations Bull. Chem. Soc. Ethiop. 2013, 27(3), 329-346.DOI: http://dx.doi.org/10.4314/bcse.v27i3.2

Highlights

Fluoroquinolones are the second-generation members of quinolone antibiotics fluorinated in position 6 and bearing a piperazinyl moiety at position
Gemifloxacin mesylate (GMF), MOX and GTF are fourth-generation synthetic broad-spectrum 8-methoxy fluoroquinolone antibacterial drug derivatives. Due to their clinical advantages, GMF, MOX and GTF are receiving a great interest and there was an increase in number of their pharmaceutical dosage forms in the market in recent past
The addition of GMF, MOX or GTF to this solution produced a new characteristic band at 610 nm (Figure 1) due to the formation of green color manganate ion, which resulted in the oxidation of the studied drugs by potassium permanganate (KMnO4) in alkaline medium (NaOH)

Summary

INTRODUCTION

Fluoroquinolones are the second-generation members of quinolone antibiotics fluorinated in position 6 and bearing a piperazinyl moiety at position. The present study describes the development and validation of a selective and simple kinetic spectrophotometric method for the determination of GMF, MOX and GTF by measuring the absorbance at 610 nm after oxidation reaction with alkaline KMnO4 in an attempt to evaluate the studied drugs in pure forms as well as in dosage forms. Stock standard solutions of GMF, MOX and GTF (100 μg mL-1) were prepared by dissolving an exact weight (10 mg) of the studied drugs in 2.0 mL of 0.05 M NaOH, and further diluted to 100 mL with double distilled water in a 100 mL measuring flask. The solutions were further manipulated as described under the general recommended procedures for each reagent and data treatment

RESULTS AND DISCUSSION

Evaluation of the kinetic parameters

CONCLUSION