DETERMINATION OF CEFTAZIDIME AND PYRIDINE BY HPLC - APPLICATION TO A VISCOUS EYE DROP FORMULATION

A stability-indicating high performance liquid chromatographic (HPLC) method was developed to determine the cephalosporin antibiotic ceftazidime and its degradation product pyridine. The method was applied to analysis of an aseptically prepared viscous ceftazidime eye drop formulation (ceftazidime 5% w/v in Sno Tears). The chromatographic conditions were: Spherisorb 5 mu m hexyl column, 100 x 4.6mm; mobile phase acetonitrile:aqueous ammonium acetate 0.05M (7:93); flow rate 2ml/min; detector wavelength 254nm. The retention times of ceftazidime and pyridine were 1.3min and 3.8min respectively. The chromatographic precision of the method was typically 0.3-0.5% relative standard deviation (RSD) for ceftazidime. The recovery of ceftazidime from the eye drop was 101.3% and the within-day precision was 0.8% RSD. The limit of detection for pyridine was 2.4ng. Ceftazidime degraded by 7% over 7 days in the eye drops, with the production of pyridine accounting for 50% of the degraded antibiotic.