Simultaneous Determination of Levofloxacin and Ornidazole by Ratiospectra Derivative Spectrophotometry and High Performance Liquid Chromatography

Rapid, precise, accurate and specific ratiospectra derivative spectrophotometry and high-performance liquid chromatography procedures were described for the simultaneous determination of levofloxacin and ornidazole in their combined dosage forms. For the first method of ratiospectra derivative spectrophotometry the signals were measured at 302 nm for ornidazole and 292.8 nm for levofloxacin as a mixture. The second method is based on high performance liquid chromatography (HPLC) on Princeton RP-C₁₈ column (5μ, 150x4.6mm) using 0.1% v/v triethylamine-acetonitrile (80:20, v/v) (pH 6.0). Detection was carried out using a UV detector at 295 nm. The retention time for levofloxacin and ornidazole were found to be 2.8 min and 4.4 min respectively. Both the methods showed good linearity in the range of 1 to 20μg/mL and 5 to 5000ng/ml for ratiospectra derivative spectroscopy and HPLC respectively.

Pharmaceutical formulations containing both drugs were successfully assayed using the developed methods.