Abstract
An accurate simple and selective kinetic procedure for the determination of certain 4-quinolones namely, norfloxacin (I), ofloxacin (II), enrofloxacin (III), fleroxacin (IV), ciprofloxacin (V) and pefloxacin (VI) is described. The procedure is based on reacting the studied compounds in acidic media (0.1 M HCL) with 3-methyl-2-benzothiazolinone hydrazone hydrochloride (MBTH) in presence of cerium (IV) ammonium sulphate as an oxidant at room temperature for a fixed time of 20 min. for (I), (III), 12 min for (II) and 30 min for IV , V and VI, then the absorbance of the reaction product is measured at 630 nm. The concentration of the studied compounds is computed using the corresponding calibration curve equation for the fixed-time method. The absorbance-concentrations plot is rectilinear over the range 20-100 ug.ml-1 for (I), 2 - 20 ug.ml-1 for (II), 10 - 74 ug.ml-1 for (III), 10 - 60 ug.ml-1 for IV, 10 - 50 ug.ml-1 for IV and 8 - 40 ug.ml-1 for VI. The determination of the studied compounds by the fixed-concentration and rate constant methods is feasible with the calibration equation obtained, but the fixed-time method proved to be more applicable. The procedure was applied successfully to commercial tablets and ampoules and the results obtained were compared statistically with the reference methods.
Highlights
The studied 4-quinolones are antibacterial agents, structurally related to nalidixic acid but with a wider antibacterial spectrum and greater activity'
Various techniques have been utilized for the determination of the studied 4- quinolone compounds either per se or in dosage forms
As the intensity of the colour increases with time, (Fig.2) this was used as a usefull kinetic method for the determination of studied 4-Quinolones either in pure form or in pharmaceutical preparations
Summary
Kinetic and Optimization of the Reaction Conditions: The reaction between the studied 4 - quinolones and MBTH in acidic medium in the presence of Ce (IV) as an oxidant yields a green colour. M. R i z k et al.: The reaction was studied under various concentrations of both the reagent and oxidant for varying time at room temperature or under the effect of heat. As the intensity of the colour increases with time, (Fig.2) this was used as a usefull kinetic method for the determination of studied 4-Quinolones either in pure form or in pharmaceutical preparations. The reaction rate was followed at room temperature with various concentrations of the studied compounds over the range. Taking logarithms of rates and concentrations (tables 1A ,lB, 1C and ID) and figure 5, equation (1) is transformed into. Table :l.A. Logarithms of rates for different concentrations of norfloxacin at room temperature at 630 nm. Table: 1.C. Logarithms of rates for different concentrations of enrofloxacin at room temperatureat 630 nm
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
