The aim of this study is to develop and validate a stability-indicating assay method for simultaneous determination of gatifloxacin and prednisolone acetate, or of ciprofloxacin hydrochloride and dexamethasone in combination and in the presence of degradation products. Reverse-phase high-performance liquid chromatography is used. All analyses were carried out on a Kinetex C18 column and acetronitrile–water (50 : 50 v/v) pH 3.0 mobile phase with 0.30 mL min⁻¹ flow rate. Efficient chromatographic separation of these drugs and their forced degradation products is achieved in less than 6 min and with a peak purity match factor higher than 950. The method shows linearity in the concentration range of 1.2 to 9.6 μg mL⁻¹ for gatifloxacin (r = 0.9995), 2.0 to 16.0 μg mL⁻¹ for prednisolone acetate (r = 0.9997), 2.5 to 25.0 μg mL⁻¹ for both ciprofloxacin hydrochloride (r = 0.9993) and dexamethasone (r = 0.9998), precision (relative standard deviation lower than 2%), accuracy (mean recovery 100 ± 2%), and robustness, according to ICH and AOAC guidelines. This method is able to determine simultaneous ophthalmic combinations of these drugs and to separate the drug peaks from their forced degradation products. Additionally, the optimized chromatographic conditions can contribute to minimize waste of organic solvent .