Identification, Isolation and Structure Confirmation of Forced Degradation Products of Sofosbuvir

Abstract

A new stability indicating reverse phase chromatographic method was developed for the analysis of Heptisis C Drug Sofosbuvir. The developed UPLC method was superior in technology to conventional RP-HPLC with respect to resolution, speed, solvent consumption and analysis cost. Sofosbuvir was subjected to the thermal, hydrolytic, oxidative, and photolytic degradation, according to ICH guidelines. The drug depicted degradation in acidic, basic and oxidative conditions and it was stable to other stress conditions (thermal and photolytic). Identified degradation products were isolated using mass supported auto purification system and characterized by NMR techniques ( 1 H NMR, D 2 O Exchange, 13 C NMR, 31 P NMR, 19 F NMR, HSQC and HMBC) and HRMS experiments. Isolated acid degradation impurity was showing molecular weight of 416.08, molecular formula C 16 H 18 FN 2 O 8 P and its name as (R)-((2R, 3R, 4R, 5R)-5-(2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)-4-fluoro-3-hydroxy-4-methyltetrahydrofuran-2-yl)methyl phenyl hydrogen phosphate. Isolated base degradation impurity-A was showing molecular weight of 453.13, molecular formula C 16 H 25 FN 3 O 9 P and its name as (S)-isopropyl 2-((R)-(((2R, 3R, 4R, 5R)-5-(2, 4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)-4-fluoro-3-hydroxy-4-methyltetrahydrofuran-2-yl)methoxy)(hydroxy)phosphorylamino)propanoate. Isolated base degradation impurity-B was showing molecular weight of 411.08, molecular formula C 13 H 19 FN 3 O 9 P and its name as (S)-2-((R)-(((2R, 3R, 4R, 5R)-5-(2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)-4-fluoro-3-hydroxy-4-methyltetrahydrofuran-2-yl)methox-y)(hydroxy)phos-phorylamino)propanoic acid. In oxidative degradation study, degradation was observed very less and with obtained quantity (less than 2 mg) recorded 1 H NMR and HRMS analysis. From the spectral data degradation product was showing molecular weight of 527.15, molecular formula C 22 H 27 FN 3 O 9 P and its name as (S)-isopropyl 2-((S)-(((2R, 4S, 5R)-5-(2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)-4-fluoro-4-methyl-3-oxotetrahydrofuran-2-yl)methoxy)(phenoxy)phosphorylamino)propanoate. The developed chromatographic method was validated as per ICH guidelines and proved suitable for the stability testing and quality control of the drug Sofosbuvir