Stability Studies and In Vitro Bioavailability of Acyclovir Loaded Ophthalmic Lyophilisate Carrier System (OLCS): Evaluation of Long-term Efficacy and Performance

The present study investigates the stability and in vitro bioavailability of an Acyclovir-loaded Ophthalmic Lyophilisate Carrier System (OLCS) designed for enhanced ocular drug delivery. Acyclovir, an antiviral drug commonly used for treating herpes simplex keratitis, faces challenges such as low bioavailability and limited corneal permeability in conventional formulations. The OLCS approach leverages lyophilized carriers to provide improved stability, controlled drug release, and targeted delivery to ocular tissues. The research evaluated the long-term stability of OLCS under different environmental conditions (accelerated and real-time) in terms of drug content, physical integrity, and reconstitution properties. Stability was assessed using analytical techniques such as high-performance liquid chromatography (HPLC) and differential scanning calorimetry (DSC). The in vitro bioavailability was studied through corneal permeation assays using excised corneal tissues, with comparison to standard acyclovir eye drops. Results showed that OLCS exhibited excellent stability over 12 months, with negligible drug degradation and preserved lyophilized structure. Reconstituted formulations displayed consistent physicochemical properties, including pH and osmolarity. In vitro bioavailability testing demonstrated significantly higher drug permeation and retention in corneal tissues compared to conventional formulations, attributed to the enhanced mucoadhesive and controlled release properties of the OLCS. The findings suggest that Acyclovir-loaded OLCS is a promising alternative to conventional ocular delivery systems, offering improved therapeutic performance and long-term efficacy. Further in vivo studies are warranted to validate its clinical applicability for managing ocular viral infections.