Contact inhibition antiviral activity of F18 EC16 suspensions in three diluents. The glycerol-based F18 EC16 nasal formulation stock (1%) was diluted 10 X with serum-free EMEM (MM), normal saline, or phosphate buffered saline (PBS) to 1.25 mM. The working suspensions were incubated with OC43 virus for 30 min at a 1:9 ratio (virus : formulation) prior to serial 10x dilution and subjected to TCID50 assay. Results are means obtained from 3 independent experiments with standard deviation (the saline test result values were identical with 0 SD). The viral titer log 10 was 9.75/ml determined from a positive control on the same plates.

Context in source publication

Context 1

... our ongoing animal study and a future human study, the F18 formulation was tested by dilution in PBS and saline, which showed comparable direct virus log 10 inhibition efficacy results (Figure 6), although dilution in PBS gave significantly greater reduction (log 10 5.41 versus log 10 4.21 (average saline and MM), equivalent to 16.2-fold better), suggesting that the phosphate content may enhance the antiviral activity, presumably by modification of the surface charge of particles. Of note, the difference is based on an already very high level of reduction (log 10 3.92-4.5 vs. log 10 5.42). ...