Laninamivir is a long-acting
antiviral requiring only a single dose for the treatment of
influenza infection, making it an attractive alternative to existing
neuraminidase inhibitors that require multiple doses over many days. Like
zanamivir,
laninamivir is administered to patients by inhalation of dry
powder. To date, studies investigating the effectiveness of
laninamivir or
zanamivir in a ferret model of
influenza infection have administered the
drug in a solubilised form. To better mimic the delivery action of
laninamivir in humans, we assessed the applicability of a Dry
Powder Insufflator™ (DPI) as a delivery method for
laninamivir octanoate (LO) in ferrets to determine the effectiveness of this
drug in reducing
influenza A and
B virus infections. In vitro characterisation of the DPI showed that both the small particle sized LO (0.7-6.0μm diameter) and the large particle sized
lactose carrier (20-100μm diameter) were effectively discharged. However, LO delivered to ferrets via the DPI prior to
infection with either A(H1N1)pdm09 or B viruses had a limited effect on nasal
inflammation, clinical symptoms and viral shedding compared to placebo. Our preliminary findings indicate the feasibility of administering
powder drugs into ferrets, but a better understanding of the pharmacokinetics and pharmacodynamics of LO in ferrets following delivery by the DPI is warranted prior to further studies.