Rifamycin SV is an ansamycin-class compound with established transporter inhibitory and anti-inflammatory properties. It differentially inhibits hepatic organic anion transporting polypeptides Oatp1 and Oatp2, with Ki estimates of 6.6 µM and 7.3 µM, respectively, for competitive inhibition of estradiol-17β-glucuronide transport. Beyond transporter modulation, rifamycin SV suppresses inflammatory cytokine and chemokine secretion from lipopolysaccharide-activated monocytes and macrophages while stimulating pregnane X receptor transcriptional activity and inhibiting NFκB-driven responses. Researchers utilize this compound to investigate Oatp-mediated drug disposition mechanisms and to explore non-antibiotic immunomodulatory signaling pathways in enteric and hepatic cell models.