FSQ spectrophotometric and HPLC analysis of some cephalosporins in the presence of their alkali-induced degradation products

Accurate and precise spectrophotometric full spectrum quantitation (FSQ) and high-performance liquid chromatography (HPLC) procedures for the quantitation of some selected cephalosporins, namely, cefotaxime, ceftazidime and ceftriaxone in the presence of their alkali-induced degradation products and in commercial injections have been described, The degradation products or formulation excipients did not interfere in the analysis, The spectrophotometric method was based on the use of FSQ software of multicomponent analysis for simultaneous determination of the examined antibiotics in the presence of their alkali-induced degradation products. The HPLC procedure was based on resolution of cefotaxime or ceftazidime or ceftriaxone from the alkali-inducted degradation products using an ODS column and mobile phase composed of acetonitrile-ammonium acetate buffer solution (0.1 M) in a ratio 10:90 (pH 7.5) with peak detection at 270 nm using a diode array detector. The collected data proved that both procedures were of comparable accuracy and precision, however, the HPLC method was of higher sensitivity (much less than 1 mu g/ml) compared to the FSQ method. Accelerated stability studies of cefotaxime, ceftazidime and ceftriaxone in aqueous solutions (pH 2-10) using the HPLC method indicated that the degradation of the antibiotics followed pseudo-first-order kinetics. The rate constant-pH profiles showed that the antibiotics were relatively stable over the pH range 4-6 with optimum stability at pH 5. The extrapolated shelf-life (t(90)) values as determined from Arrhenius plots at pH 5 and 25 degrees C were 6.56, 2.14 and 0.88 h for cefotaxime, ceftazidime and ceftriaxone, whereas these values were found to be 15.0, 3.62 and 2.14 h, respectively at 4 degrees C. (C) 1998 Elsevier Science S.A. All rights reserved.