Investigation of the spectrofluorimetric behavior of azelastine and nepafenac: Determination in ophthalmic dosage forms.

The first spectrofluorimetric report investigating the fluorimetric behavior of the antihistaminic drug, azelastine (AZEL), and the non-steroidal anti-inflammatory drug, nepafenac (NEP), either in bulk or in their dosage forms, eye drops and ophthalmic suspension. After a full investigation of the factors that may influence their spectrofluorimetric behavior: pH, different organized media and organic solvents, the optimum factors were set in order to enable the analysis of each drug with maximum sensitivity. The AZEL spectrofluorimetric analysis was set at 286/364 (λex/λem) in distilled water while for NEP, the analysis was set at 228/303 (λex/λem) in methanol. The linearity range for AZEL was from 0.1 to 1.5 μg/mL while that of NEP was from 0.2 to 1.5 μg/mL. The linearity yielded good regression parameters with low LOD (0.022 and 0.032 μg/mL for AZEL and NEP, respectively) and LOQ (0.073 and 1.08 μg/mL for AZEL and NEP, respectively) when compared with those obtained from many previous spectroscopic and chromatographic reports in literature. The method was ICH validated and was applied to the analysis of AZEL and NEP with good selectivity regarding the inactive ingredients.