Metabolite identification and quantitation of RBD1016 siRNA: a direct comparison of hybridization-based LC-FD and LC-HRAM assays

Abstract

Aim: RBD1016 is an N-acetylgalactosamine-conjugated siRNA drug currently in a phase II trial for treatment of chronic hepatitis B virus. To evaluate its absorption, distribution, metabolism and excretion (ADME) and pharmacokinetic/pharmacodynamic (PK/PD) properties, two LC-based bioanalytical methods, LC–high-resolution/accuracy MS and LC–fluorescence detection, were developed and qualified. Materials & methods: The LC–high-resolution/accuracy MS method was used for metabolite identification and simultaneous quantitation of the antisense and sense strands as well as their respective metabolites. The LC–fluorescence detection assay was primarily used for analyzing the antisense strand and its metabolites in low-concentration plasma samples. The two methods were successfully bridged by analyzing the same sets of study samples. Results & conclusion: Both methods were found to have excellent accuracy/precision, specificity and reproducibility to support ADME and PK/PD studies of RBD1016 siRNA.