Simultaneous Estimation of Ceftazidime and Ceftizoxime in Pharmaceutical Formulations by HPLC Method

The aim of the present study was to develop a fast, sensitive and reliable method for rapid screening of cephalosporin injectable dosage forms namely ceftazidime and ceftizoxime to the detection of counterfeit and substandard drugs that might be illegally commercialized. Ceftazidime, ceftizoxime and cefixime (IS) were separated in a X-Terra RP-18 column (250 x 4.60 mm ID x 5 mu) and DAD detector set at 290 and 260 nm. The mobile phase consisted of a mixture of methanol: water 20:80 (v/v) at a flow rate of 1.0 mL min(-1). Additionally, in order to find the optimum pH value of separation the pK(a) values of studied compounds were determined by using two different methodologies. Aqueous pK(a) values of studied compounds have been determined by UV-spectrophotometry and liquid chromatography were used for the determination and direct characterization of the dissociation constants by using the dependence of the capacity factor on the pH of the mobile phase in 20% (v/v) methanol-water binary mixture in which separation was performed. The pH of the mobile phase was adjusted with 25 mM H3PO4 to 3.2. The method was shown to be linear, sensible, accurate, and reproducible over the range of analysis and it can be used to pharmaceutical formulations containing a single active ingredient within a short analysis time.