Scientific Research and Essays Vol. 2 (8), 348-352, August 2007          
ISSN 1992-2248 © 2007 Academic Journals

Full Length Research Paper

Spectrophotometric determination of some cephalosporin antibiotics using Prussian blue reaction

Nkeoma N. Okoye¹, Godwin I. C. Nwokedi¹, Nkechinyere N. Ukwueze¹ and Festus B. C. Okoye²*

¹Department of Pure and Industrial Chemistry, University of Nigeria, Nsukka, 41001, Enugu State, Nigeria.

²Department of Pharmaceutical and Medicinal Chemistry, University of Nigeria, Nsukka, 41001, Enugu State, Nigeria.

*Corresponding author. E-mail: basdenc@yahoo.com. Phone: +234-8033607639.

Accepted 5 July, 2007

A simple, sensitive and accurate spectrophotometric method of analysis of ceftriaxone, cefotaxime and cefuroxime in pharmaceutical dosage forms has been developed and validated. The method is based on the formation of Prussian Blue (PB) complex. The reaction between the acidic hydrolysis product of the antibiotics (T = 70^○C) with the mixture of Fe³⁺ and hexacyanoferate (III) ions was evaluated for the spectrophotometric determination of the antibiotics. The maximum absorbance of the coloured complex occurred at λ = 700 nm and the molar absorptivity is 3.0 x 10⁴ l.mol^-1 cm^-1. Reaction conditions have been optimized to obtain PB complex of high sensitivity and longer stability. Under optimum conditions the absorbance of the PB complex were found to increase linearly with increase in concentrations of ceftriaxone, cefotaxime and cefuroxime, which corroborated with the correlation coefficient values. The linear range of the calibration graph was 2 - 20 μg/ml for ceftriaxone and cefotaxime and 2 - 18 μg/ml for cefuroxine. The proposed method was successfully applied to the determination of the selected antibiotics in bulk drugs and pharmaceutical formulations and the results obtained agree well with the labeled contents.

Key words: Cephalosporins, β-lactam antibiotic, spectophotometric, Prussian Blue.