Rifaximin-d6

Rifaximin-d6 is the stable isotope-labeled counterpart of Rifaximin. Rifaximin is an orally administered semisynthetic antibiotic derived from rifamycin SV, mainly used to treat gastrointestinal diseases such as traveler’s diarrhea caused by Escherichia coli, hepatic encephalopathy, and irritable bowel syndrome. Rifaximin exerts antibacterial activity by binding to the β subunit of bacterial DNA-dependent RNA polymerase, thereby inhibiting bacterial RNA synthesis. It shows higher sensitivity against Gram-positive strains, with minimum inhibitory concentration (MIC) values ranging from nanomolar to micromolar levels, whereas MICs against Gram-negative bacteria are higher. Because Rifaximin is hardly absorbed after oral administration and acts primarily in the intestinal tract, systemic adverse reactions are relatively few. As a deuterated compound of Rifaximin, Rifaximin-d6 is commonly used in pharmacokinetic studies, particularly as an internal standard in liquid chromatography–mass spectrometry (LC-MS) analysis to improve the accuracy and reliability of quantitative analysis. The dose or concentration used in experiments typically depends on the experimental design and research objectives.