Multistep Synthesis of Novel Impurities of Azelastine Hydrochloride

Azelastine hydrochloride is an important active pharmaceutical ingredient (API) used in treatment of asthma patients, with high global consumption. According to ICH guidelines, the identification and characterization of impurities in APIs are mandatory to ensure drug safety and efficacy. During the synthesis of azelastine hydrochloride, a total of six impurities were identified and reported: azelastine impurity A, azelastine impurity C, azelastine impurity D, azelastine N-oxide, azelastine desmethyl, azelastine desmethyl nitroso. We synthesized all seven impurities through novel synthetic route and characterization were performed using various spectroscopic techniques, including FTIR, NMR, MS, and HPLC. The application of these techniques provided in detail insights into the chemical composition and purity of each impurity. Our study contributes valuable knowledge to the pharmaceutical field by enhancing impurity profiling by azelastine HCl, which is essential for regulatory compliance and quality control. The results reported here can be used for manufacturing of effective formulations of azalestine HCl