Oseltamivir acid (GS 4071)，Oseltamivir phosphate 的活性代谢产物, 是流感病毒神经氨酸酶 (IC50=2 nM) 的口服生物有效的，选择性的抑制剂，对流感病毒 A 和 B 都有活性。 Oseltamivir acid (GS 4071), the active metabolite of Oseltamivir phosphate, is an orally bioavailable, potent and selective inhibitor of influenza virus neuraminidase (IC50=2 nM) with activity against both influenza A and B viruses。