STUDYING THE ACCELERATED PHOTOSTABILITY OF CIPROFLOXACIN AND LOMEFLOXACIN IN TABLETS AND EYE DROPS

The photostability of two fluoroquinolones: ciprofloxacin and lomefloxacin have been detected in tablets, and eye drops formulations using light-stability cabinet. Ciprofloxacin and lomefloxacin were subjected to stress conditions. The degradation products were well separated from the peak of the active substance. The stability of these compounds has been studied both in containers and under direct light in the light-stability cabinet. Samples were assayed immediately and at 1, 3, 6 months by stability-indicating high-performance liquid chromatography methods with a photodiode array detector.  The determination was performed on C18 (250 × 4.6 mm, 5 µm). The first mobile phase consisted of 0.025M phosphoric acid, and acetonitrile (87:13) pumped at a flow rate 2ml/min for ciprofloxacin, while the second consisted of water, acetonitrile, triethylamine (80:20:0.3) pumped at a flow rate 1ml/min for lomefloxacin. The UV detector was operated at 278 nm for ciprofloxacin and 288 nm for lomefloxacin. The methods were suitably validated for linearity, accuracy, precision, robustness, and selectivity. All validation parameters were within the accep-tance range. Data analysis revealed that plastic and amber containers could not protect either ciprofloxacin or lomefloxacin in eye drops formulation from photodegradation after one month in the cabinet. White blister protects the two agents in tablets formulation after six months in the cabinet.