A simple method for the spectrophotometric determination of cephalosporins in pharmaceuticals using variamine blue

Chand Pasha,Badiadka Narayana

doi:10.26850/1678-4618eqj.v33.2.2008.p41-46

Abstract

A simple spectrophotometric method for the determination of cefotaxime, ceftriaxone, cefadroxil and cephalexin with variamine blue is presented. The determination is based on the hydrolysis of β-lactam ring of cephalosporins with sodium hydroxide which subsequently reacts with iodate to liberate iodine in acidic medium. The liberated iodine oxidizes variamine blue to violet colored species of maximum absorption at 556 nm. The absorbance is measured within the pH range of 4.0-4.2. Beer’s law is obeyed in the range of 0.5-5.8 μg mL–1, 0.2-7.0 μg mL–1, 0.2-5.0 μg mL–1 and 0.5-8.5 μg mL–1 for cefotaxime, ceftriaxone, cefadroxil and cephalexin respectively. The analytical parameters were optimized and the method is successfully applied for the determination of cefotaxime, ceftriaxone, cefadroxil and cephalexin in pharmaceuticals.

Highlights

Cephalosporins structurally differ from pencillins by the heterocyclic ring system
This method is based on the hydrolysis of ß-lactum ring of the analytes on heating with sodium hydroxide and the reaction of the hydrolysed product with potassium iodate in acidic medium to which liberates iodine
Determination of cefotaxime, ceftriaxone, cefadroxil, and cephalexin are represented in scheme 1

Summary

Introduction

Cephalosporins structurally differ from pencillins by the heterocyclic ring system. Cephalosporins are pencillinase-resistant antibiotics with significant activity against both gram-positive and gram-negative bacteria. The key intermediate for semisynthetic production of a large number of cephalosporins is 7-aminocephalosporanic acid, which is formed by hydrolysis of cephalosporin C produced by fermentation [1]. A few thousand semisynthetic cephalosporins have been described in the scientific literature, but only a small number of these has shown clinical importance. Cefotaxime, ceftriaxone, cefradine and cephalexin are β-lactam antibiotics possessing a broad spectrum of antibacterial properties [2,3]. Several methods have been reported for the quantitative determination of cephalosporins. Cefotaxime, ceftriaxone and cefradine were determined in pharmaceuticals preparations [11,12,13,14,15], Urine [14,16,17,18,19] and human serum [20]. A rapid development of chromatographic determination methods of pharmaceuticals has been observed too [21,22]

Methods

Results

Conclusion