An integrated paradigm between green analytical chemistry and quality-by-design for robust analysis of alcaftadine and ketorolac tromethamine in aqueous humor via sustainable chromatographic methods

The field of pharmaceutical industry has witnessed the launch of a new co-formulated eye drop, composed of alcaftadine and ketorolac tromethamine, for alleviating allergic conjunctivitis. Such new formulation evokes the need for a sensitive, robust and fast analytical method capable of their quantification in their dosage form, in aqueous humor for pharmaco-kinetics studies as well as in presence of plausible degradation products. In this work, two validated stability-indicating chromatographic methods were developed for alcaftadine and ketorolac assaying with good adherence to values of green analytical chemistry. Drugs stabilities were tested under various stress conditions where drugs showed liability for oxidative degradation only. For the first chromatographic method, an integrated merger between analytical quality-by-design and green analytical chemistry was implemented via a UPLC method coupled with photo-diode array detector. A short C18 analytical column of 100 mm was utilized with mobile phase of ethanol: aqueous solution pH 4.0 containing 0.1% triethylamine (40: 60, by volume). Second method was thin layer chromatographic one using HPTLC silica plates as a stationary phase and a developing system of dichloromethane: ethanol (5:4, by volume). Both methods achieved to selectively quantify the studied drugs with high accuracy and precision without any interference from degradation products or related excipients in eye drops. The methods were also successfully exploited for ALF and KTC assaying in rabbit aqueous humor, with no need for prior extraction procedures, for further pharmacokinetic studies. Finally, usage of green solvents gives us the advantage of applying various evaluation tools to conclude method greenness. [Display omitted] •Two novel stability-indicating methods for alcaftadine and ketorolac analysis.•Characterization of oxidative degradation products by IR and mass spectroscopy.•Integrating green analytical chemistry with AQbD for robust UPLC development.•Successful analysis in dosage form & aqueous humor as well as degradation products.•Assuring greenness profile of the proposed methods via smart metric tools.