Development of a stability indicating high-performance liquid chromatography method for determination of cenobamate: study of basic degradation kinetics

Abstract This study presents a stability indicating high-performance liquid chromatography HPLC method for the determination of cenobamate (CNB) in presence of its main impurity (CNB H-impurity) and degradation products. The chromatographic separation was carried out on a Thermo BDS Hypersil-C18 column (150 × 4.6 mm; 5 μm) with a mobile phase consisting of a 50:50 (%v/v) ratio of methanol and purified water. The flow rate was maintained at 1.0 mL. min− 1. CNB was detected at 210 nm using a PDA detector. The column temperature was held at 40 °C.The retention time of the drug was found to be 3.2 min. Furthermore, the study investigates the degradation behavior of CNB under various stress conditions, including acidic, basic, oxidative, and light-induced degradation. The results indicate that CNB is particularly susceptible to basic degradation. Consequently, a comprehensive study of the basic degradation kinetics was conducted. The method was also successfully applied for the determination of CNB in its dosage form. The results also show that there is no co-elution from degradation products or excipients as indicated by the mass balance and peak purity values confirming the specificity of the proposed method and its applicability for routine analysis of CNB.