Zanamivir is an influenza viral neuraminidase inhibitor with IC₅₀ values of 0.95 nM and 2.7 nM for influenza A and B, respectively. IC50 & Target: IC50: 0.95 nM (Influenza A); 2.7 nM (Influenza B)^[1] In Vitro: Zanamivir interacts with a group of amino acids in the active site of neuraminidase, which are conserved in all influenza A and B strains. Zanamivir blocks the action of neuraminidase, which prevents the cleavage of sialic acid on the cell receptors, thus preventing release and spread of the newly formed virions^[2]. In Vivo: Zanamivir has a poor bioavailability in oral administration, with only 4–17% of the agent. Oral delivery of zanamivir has been a problem due to its strong hydrophilic nature that limits its transport across the intestinal epithelium. Permeation enhancers such as sodium cholate, hydroxypropyl β-cyclodextrin could be used with zanamivir to enhance the intestinal permeability^[3].