ABSTRACT
In this work the photostability of two fluoroquinolones: ciprofloxacin and lomefloxacin has been detected in tables 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 photodiode array detector. The determination was performed on C18 [250 x4.6mm, 6 micro m]. 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 was suitably validated for linearity, accuracy, precision, robustness and selectivity. All validation parameters were within the acceptance range. Data analysis revealed that plastic and amber containers can not protect either ciprofloxacin or lomefloxacin in eye drops formulation from photodegradation after one month in the cabinet. White blister protect the two agents in tablets formulation after six months in the cabinet