Rebamipide and Lansoprazole: Therapeutic Complementarity and A Critical Review of Analytical Approaches

Rebamipide and lansoprazole act through different mechanisms, but their effects can complement each other in the management of acid-related gastrointestinal disorders. Lansoprazole decreases gastric acid secretion by inhibiting the gastric H⁺/K⁺-ATPase, while rebamipide mainly supports mucosal defence by enhancing prostaglandin-related protection, mucus production, epithelial repair, and antioxidant and anti-inflammatory responses. The therapeutic relevance of these complementary actions has also increased the need for reliable analytical methods for pharmaceutical quality assessment. This review presents the reported analytical approaches used for the determination of rebamipide and lansoprazole in pharmaceutical formulations and biological matrices. Various techniques, including HPLC, RP-HPLC, UPLC, LC–MS/MS, HPTLC, and spectrophotometry, are discussed with respect to their chromatographic conditions, detection principles, validation characteristics, and practical applications. The reviewed methods have been applied to assay determination, formulation analysis, stability studies, related-substance evaluation, pharmacokinetic investigations, and routine quality control. Particular emphasis is placed on the analytical difficulties associated with the simultaneous determination of both drugs, since their different physicochemical and chromatographic properties can affect separation and quantification. The review also considers the importance of systematic method development, Analytical Quality by Design (AQbD), stability-indicating capability, robustness, and validation in line with current ICH recommendations. Overall, the available analytical literature provides several useful approaches for individual and multicomponent analysis, while also indicating scope for developing methods with improved selectivity, robustness, and efficiency. These aspects are important for establishing a reliable and fit-for-purpose analytical procedure for the simultaneous quality evaluation of rebamipide and lansoprazole.