Stability-Indicating RP-HPLC Method Development for A Fixed-Dose Combination Tablet and Its Degradation Kinetics

Pharmaceutical formulations stability is an important factor in drug development and drug quality control. The goals of this work were to establish and qualify a stability-indicating reverse-phase high-performance liquid chromatography (RP-HPLC) method to measure active pharmaceutical ingredients in a fixed- dose combination admixture tablet simultaneously and to assess the degradation kinetics of the Active pharmaceutical ingredients under different stress conditions. The concentration using C18 column and acetonitrile-phosphate buffer mobile phase proved to be optimal in terms of separating the APIs with great resolution, symmetric peaks and reproducibility. The results of the forced degradation studies indicated that stress due to acidic and oxidative conditions appeared to be the most significant stressors, whereas thermal and photolytic stress had little effect. First-order kinetic models were used to describe the degradation that was confirmed to be significantly different under different stress conditions using statistical testing. The validated technique was robust and sensitive and could be applied in regular quality checks; the information helped understand the stability of the formulation and shelf-life.