ICRF-Assisted Box-Behnken Design and Optimization for Rapid UPLC-PDA Determination of Dorzolamide Hydrochloride and Timolol Maleate in an Ophthalmic Preparation

BACKGROUND: Simultaneous optimization of chromatographic resolution and analysis time constitutes a significant analytical challenge in multicomponent pharmaceutical analysis, as resolution-driven optimization strategies may improve peak separation without providing explicit control over retention time, often resulting in unnecessarily prolonged runtimes. To address this limitation, an optimization strategy based on a Box-Behnken experimental design was implemented in conjunction with the Improved Chromatographic Response Function (ICRF), which integrates separation quality and analysis time within a single mathematical objective function. OBJECTIVE: This strategy describes the development of a rapid, chemometrically optimized UPLC-PDA method for the simultaneous determination of dorzolamide hydrochloride (DH) and timolol maleate (TI) in a commercial ophthalmic preparation. METHOD: A Box-Behnken experimental design and optimization approach was employed in combination with an Improved Chromatographic Response Function (ICRF), which integrates resolution, peak overlap, peak width, and runtime into a single composite objective function. This strategy enabled short runtime (or short retention time of analytes in a chromatogram) while preserving adequate peak separation. RESULTS: Under the optimized conditions, complete chromatographic separation was achieved within 3 min using a BEH C18 column and a mobile phase consisting of acetonitrile and 4 × 10-4 M CCl3COOH (60:40, v/v) at a flow rate of 0.32 mL/min with detection at 275 nm. The method demonstrated excellent linearity over the range of 5.0-40.0 µg/mL (r > 0.999), with limits of detection of 0.51 µg/mL for DH and 0.61 µg/mL for TI. Mean recoveries were 99.9% and 99.5% for DH and TI, respectively, with satisfactory precision and robustness. CONCLUSION: The proposed ICRF-assisted optimization approach provided high-resolution separation within minimal runtime and was successfully applied to the routine quality-control analysis of a commercial ophthalmic formulation. HIGHLIGHTS: The study demonstrates the effectiveness of composite response-based chemometric optimization in enhancing analytical efficiency in pharmaceutical drug analysis.