Avatrombopag maleate (AOG), a thrombopoietin receptor agonist, is a generic drug for which a viable route of synthesis has been identified, in which three nitrosamine drug substance-related impurities (NDSRIs) have been identified. In silico toxicity assessment has been carried out. Being product specific NDSRIs, the specification limit has been defined based on Carcinogenic Potency Categorization Approach (CPCA) approach and selective and sensitive LC-MS/MS-based analytical method developed and validated for their trace level with predefined parameters with results outcome, which are specificity, linearity with r2 between 0.9905 and 0.9999, the LOD as 0.34 ppm, and LOQ as 0.67 ppm for all impurities; the obtained recovery was in the range of 94.0%-105.6% with a SD range between 0.6 and 2.8. The overall mean between the method precision and intermediate precision studies was in the range of 6.43-6.81 ppm, and the overall % RSD for the 12 determinations was between 1.3 and 2.4. The method robustness has also been demonstrated with deliberate variations. The solution stability was studied for about 24 h to assess the nature of the solutions prepared. Further, to assess the fate of each NDSRIs, the sample was inflicted to acid, base, oxidative, thermal, and photolytic stress conditions. This intensive stress study concluded that the identified NDSRIs are carried from the starting material of secondary amine scaffolds in the reaction conditions and not a degradation product. Thus, in this current research work, we revealed three new potential NDSRIs for the AOG drug substance, their toxicity assessment, and CPCA scoring to arrive at the specification limit (Category 3 → AI 400 ng/day → 6.6 ppm as target level). The source of the NDSRI formation has also been demonstrated; finally, their selective, sensitive, and stability indicating LC-MS/MS-based analytical method has been implemented. This wholistic lifecycle approach eliminates the risk-assessment gaps and ratifies the regulatory requirements, thereby endures the product quality and patients safety.
VENKATARAO et al. (Wed,) studied this question.