Selective and Sensitive Chromatographic Methods for Determination of a Co-Formulated Binary Mixture in Antibacterial Eye Drops and Aqueous Humor in the Presence of Their Degradation Products and Potential Impurities.

Prednisolone acetate (PDN) is a corticosteroid anti-inflammatory liable to degradation under different conditions and used with antibiotics in eye drops. Two selective stability-indicating separation techniques were developed for simultaneous determination of PDN and moxifloxacin HCl (MXF) binary mixture in pure forms, ophthalmic formulation, in the presence of PDN impurities and in the presence of their degradation products. The first method was based on HPTLC separation using silica gel 60 F254 HPTLC plates, and a developing system of toluene: ethyl acetate: methanol: ammonia (5.0: 6: 2.0: 0.05, v/v/v/v) is used with detection at 254 nm. The second method was HPLC using a mobile phase of acetonitrile: methanol: deionized water, pH 2.8 (25.0: 35.0: 40.0, v/v/v), at 254 nm. A kinetic study utilizing the developed HPLC method for PDN degradation under different stress conditions was performed. Furthermore, the method was applied for determination in rabbit aqueous humor. Validation was conducted as per ICH guidelines, and system suitability was ascertained. The calibration curves were constructed in the range 0.10-25.00 and 0.20-50.00 μg band-1, for PDN and MXF by HPTLC, while for HPLC, it was 0.02-50.00 and 0.10-50.00 μg mL-1 for both drugs, in order.