Study of the antiallergic component of inosine pranobex (Inosiplex, Isoprinosine).

Inosine pranobex (INPX) at concentrations greater than 10(-3) M inhibits significantly the concanavalin A or antihuman IgE induced histamine release from human mast cells. The inosine moiety of the compound does not contribute to this effect, but rather interferes with it. The other component, the salt of dimethylaminopropanol and acetamidobenzoic acid, produces a small but significant inhibition of the histamine release already at 10(-6) M. This effect is due to the acetamidobenzoic acid although the base (dimethylaminopropanol) adds to it. With increasing incubation time, the salt of dimethylaminopropanol and acetamidobenzoic acid looses its histamine release inhibiting effect.