A Validated Quantitative 1H Nuclear Magnetic Resonance (1H-qNMR) Method for Quantification of a Novel Anti-Coagulant Drug (Betrixaban Maleate) with Assessing Its Stability by Application to Degradation Study

A highly rapid, specific, and simple quantitative proton nuclear magnetic resonance (1H-qNMR) method was established for quantification of a novel anti-coagulant drug; betrixaban maleate (BET) in its pure form and laboratory prepared dosage form. The NMR analysis was operated by using a 400 MHz NMR instrument. The deuterated solvent selected was dimethyl sulfoxide-d6 (DMSO-d6), while the internal standard used was phloroglucinol. The quantitative determination was based on the selective proton signal of BET at (3.87 ppm; singlet), while for phloroglucinol (internal standard) at (5.67 ppm; singlet). Different acquisition NMR parameters were studied and optimized to improve the sensitivity and accuracy of the proposed method. The performed method showed linearity over the concentration range of (0.1 - 8.0 mg.mL-1), with limit of detection (LOD) of 0.019 mg.mL-1 and limit of quantification (LOQ) of 0.057 mg.mL-1. The method was validated according to the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) guidelines and compared by other reported ones. The result showed satisfying agreement, as there was no significant difference as illustrated by both student's t-test and the variance ratio F-test. Moreover, the study included the expected degradation pathway of BET which was derived by assessing the stability of the drug under different stress conditions as basic, acidic, neutral, oxidative, and photolytic degradation according to ICH guidelines.