Study on the forced degradation behaviour of ledipasvir: Identification of major degradation products using LC-QTOF-MS/MS and NMR.

Ledipasvir, a novel NS5A inhibitor is used in the management of hepatitis C virus infections. The drug was subjected to forced degradation studies as per the conditions prescribed in ICH Q1 (R2) guideline. Ledipasvir degraded in hydrolytic (acid, alkaline and neutral) and oxidative stress conditions. The drug was found to be stable in thermal and photolytic conditions. Eight novel degradation products were obtained and were well separated using an HPLC C18 stationary phase (150×4.6mm, 5μm) and mobile phase composed of formic acid/acetonitrile in gradient elution mode. All the degradation products were characterised using tandem mass spectrometry with a time-of-flight analyser and the major degradation products of hydrolytic and oxidative stress were isolated and their structural confirmation was studied using H and C NMR. A well resolved chromatographic method proposed in this study suggests that the proposed analytical method finds its application as a stability indicating assay method for the drug and can be used in routine analysis.