Identification and Structural Characterization of Forced Degradation Impurities of Sacubitril by HRMS – Development and Validation of a Stability indicating RP-HPLC method

The current work identifies and characterises the stress degradation products of the anti-hypertensive drug sacubitril. The stability profile of sacubitril was evaluated under several stress settings including hydrolytic, oxidative, thermal and photolytic conditions in accordance with ICH recommendations. The degradation products of sacubitril were separated using reverse phase liquid chromatography and structural characterization was carried out using HRMS. The chromatographic separation was carried out by Reverse Phase-High Performance Liquid Chromatography (RP-HPLC) using a Fortis C18 column (150 mm X 4.6 mm; 5μm particle size) with mobile phase A (consisting of 0.1% TFA in Milli-Q water) and mobile phase B (100% Acetonitrile) in gradient mode. With a sample injection volume of 10μL, the mobile phase flow rate was 0.7 mL/min. A quadrupole time-of-flight (Q-TOF) mass spectrometer was used for the LC-MS analysis. Sacubitril is relatively stable in oxidative, thermal and photolytic conditions; however, considerable degradation was observed in acid, base and neutral hydrolysis. Three degradation products were identified and the structural characterization of these impurities was performed using the HRMS data and mass fragmentation. The proposed RP-HPLC method was robust, precise and specific in determining the impurity profile of sacubitril under different stress conditions.