Study on the molecular interactions between givosiran and theophylline by surface-enhanced Raman spectroscopy, biolayer interferometry, and visible/fluorescence spectroscopy.

[Display omitted] • Interaction between small-interfering ribonucleic acid givosiran and theophylline. • SERS, BLI, and Vis/FL methods coordinated for molecular interactions. • Clinical indication for combined use of givosiran and CYP enzyme substrates. Givosiran is a small-interfering ribonucleic acid (siRNA) drug used to treat acute hepatic porphyria. As an exogenous double-stranded RNA, givosiran has a specific spatial conformation. When they coexist, givosiran and small-molecule drugs may interact through non-covalent bonds, which may affect their efficacies. This study aimed to evaluate the molecular interaction between givosiran and three structurally-related small-molecule drugs. We combined surface-enhanced Raman spectroscopy, biolayer interferometry, and visible/fluorescence spectroscopy with a methylene blue probe to study the molecular interaction between givosiran and theophylline, caffeine, and theobromine. Molecular interactions were observed only between theophylline and givosiran, with an affinity constant (K D) of 64.2 μM. The main binding forces were hydrogen bonds and van der Waals forces, and the equilibrium binding constant (K A) was 1.855 × 104 L·mol−1. This study focused on the 5 W (Whether, Where, Why, hoW about the tendency, hoW strong) issues of the molecular interaction between givosiran and small-molecule chemical drugs. Our findings contradict the previous perception that the probability of drug–drug interactions (DDI) between nucleic acid and small-molecular drugs is low. Our study illustrates that a combination of direct and indirect analytical methods will pave a new way for future siRNA-related unknown interactions studies. [ABSTRACT FROM AUTHOR]