This study comprehensively evaluated the physical and chemical stability of fixed-dose combination (FDC) tablets containing Escitalopram and Clonazepam, crucial for treating psychiatric disorders, under various International Conference on Harmonization (ICH) compliant storage conditions. The research aimed to establish the shelf-life and understand the degradation profiles of these sensitive drugs. Three batches of FDC tablets were subjected to accelerated (40°C/75% RH), intermediate (30°C/65% RH), and long-term (25°C/60% RH) stability testing for up to 24 months. Physicochemical properties, drug content, impurity levels, and dissolution profiles were monitored using validated analytical techniques, including High-Performance Liquid Chromatography (HPLC) and Liquid Chromatography-Mass Spectrometry/Mass Spectrometry (LC-MS/MS). The results confirmed that the tablets maintained their physical and chemical stability, meeting all regulatory specifications throughout the study period. Degradation kinetics followed first-order kinetics, and the study successfully established a shelf-life of at least 24 months under the tested conditions. This research provides critical data for regulatory approval, manufacturing quality assurance, and safe patient use of Escitalopram and Clonazepam FDC tablets.

Keywords: Escitalopram, Clonazepam, Fixed-Dose Combination (FDC) Tablets, Stability, Shelf-life Determination, ICH Guidelines, Accelerated stability testing, Intermediate stability testing, Long-term stability testing, Physicochemical properties, Drug content, Impurity levels, Dissolution profiles, HPLC (High-Performance Liquid Chromatography), LC-MS/MS (Liquid Chromatography-Mass Spectrometry/Mass Spectrometry), Degradation kinetics, First-order kinetics, Psychiatric disorders, Anxiety, Depression, SSRI (Selective Serotonin Reuptake Inhibitor), Benzodiazepine, Active Pharmaceutical Ingredients (APIs), Regulatory approval, Quality assurance, Packaging materials, Degradation pathways, Kinetic modeling, Arrhenius equation, Regression analysis, ANOVA (Analysis of Variance), Good Manufacturing Practices (GMP).