Simultaneous quantification of lifitegrast and Rebamipide in hydrogel-based contact lenses using spectroscopic method

Lifitegrast (LIF) and Rebamipide (REB) are used in effective therapies of dry eye disease (DED). However, conventional eye drops often suffer from poor ocular bioavailability due to rapid pre-corneal clearance and short residence time. Drug-eluting contact lenses have emerged as a promising platform for sustained ocular drug delivery, yet no validated method exists for the simultaneous estimation of LIF and REB in such systems.

The present study aimed to develop and validate a simple, robust, and cost-effective UV spectrophotometric method for the simultaneous quantification of LIF and REB in hydrogel-based contact lenses using Vierordt's method.

Simultaneous estimation was carried out in methanol and simulated tear fluid using Vierordt's simultaneous equation approach. The method was validated according to ICH Q2 (R1) guidelines. Drug-loaded hydrogel contact lenses were prepared by free radical polymerization and evaluated for drug content, sterilization-induced leaching, and in-vitro release behavior.

Maximum absorbance was observed at 259 nm for LIF and 229 nm for REB. Calibration curves demonstrated excellent linearity (R² = 0.9999). The method tested showed high accuracy (99.9-100.5% recovery), precision (RSD < 1.5%), and sensitivity. Average drug loading per lens was 199.67 ± 0.38 µg for LIF and 80.08 ± 0.17 µg for REB. Furthermore, in-vitro release studies demonstrated sustained release for both drugs, with LIF completing release by 5 h and REB by 7 h.

The validated UV spectrophotometric method provides a novel and practical analytical tool for the simultaneous estimation of Lifitegrast and Rebamipide in therapeutic contact lenses. Its simplicity and reliability support its translational potential for routine quality control and formulation development in ocular drug delivery for DED.