Impressive merger between green analytical approaches and quality- by-design for alcaftadine determination in eye drops and rabbit aqueous humor; application to stability study by two validated chromatographic methods

Nowadays, the main target of many researchers is to develop green environmentally friendly techniques that could separate drugs without using hazardous solvents which may lead to a dreadful impact on the environment. Proceeding from this lofty goal, the main concern of this work is to develop two green chromatographic techniques, namely, HPLC and TLC to determine alcaftadine (ALF) in pharmaceutical formulation, rabbit aqueous humor, and in presence of its degradate. Fortunately, and for the first time in the history of ALF analysis, the developed HPLC technique in this work succeeded to determine ALF in the presence of its oxidative degradate via a fruitful integration between green analytical chemistry and analytical quality-by-design resulting in increasing efficiency and minimizing environmental impacts. Utilizing an XBridge (R) C18 (4.6 x 250 mm, 5 mu m) column, optimized chromatographic separation was accomplished utilizing isocratic elution with an ammonium acetate buffer (pH 5.0): ethanol (60:40, by volume) as the mobile phase, a flow rate of 1.5 mL/min, and UV detection at 282.0 nm. Over a concentration range of 0.1 to 8.0 mu g/mL, linearity was attained. Additionally, this work succeeded to determine ALF through a stability indicating study using thin layer chromatographic technique on TLC plates precoated with silica gel 60F-254 as a stationary phase using a developing system consisting of dichloromethane: ethanol: ammonia (5:5:0.1, by volume) and scanned at 282.0 nm with 0.5-20.0 mu g/band linearity range. Finally, the proposed methods were further assessed for their greenness profile using various greenness assessment tools. Fortunately, the developed methods proved to be safe, green, and eco-friendly.