Non-ionic surfactant nano-emulsions have extensive anti-microbial activity
and are biocompatible with skin and mucous membranes at effective concentra
tions. Two nano-emulsion formulations (8N8 and 20N10) made from soybean oil
, tributyl phosphate and Triton X-100, were tested for their ability to pre
vent murine influenza virus pneumonia in vivo. In the initial study, CD-1 m
ice were administered various dilutions of the nano-emulsions intranasally,
and safe dosages and concentrations were determined. Non-toxic concentrati
ons of the nano-emulsions were then mixed with influenza virus and applied
to the nares of mice. Animals receiving mixtures of two different emulsions
(8N8 or 20N10) and a LD,, of virus survived the challenge without evidence
of viral infection. To determine if the nano-emulsions could prevent influ
enza virus infection in vivo when used as a prophylactic treatment, the nan
o-emulsions (8N8 at 1.0% and 20N10 at 1.0% or 0.2%) were applied to mouse n
ares 90 min before exposure to 5 x 10(5) p.f.u./ml virus by nebulized aeros
ol. Animals pretreated with the nano-emulsions had significantly decreased
clinical signs of infection. Only 26.0% (8N8 at 1.0%), 31.25% (20N10 at 1.0
%) and 37.0% (20N10 at 0.2%) of animals pretreated with nano-emulsion died
from pneumonitis, whereas >80.0% of mock pretreated animals succumbed to in
fection (P < 0.005). These findings suggest that nonionic surfactant nano-e
mulsions have therapeutic potential for the prevention of influenza virus i
nfection in vivo.