Plasma protein binding of levamisole in several species

The binding of levamisole to total plasma proteins of 6 animal species was determined in vitro by equilibrium dialysis. The percentage of bound drug protein was independent of levamisole concentration within the range studied, 5-50 micrograms/ml (ANOVA). Levamisole was bound to a low extent to plasma proteins of each animal species (19.40-25.91%). There were significant differences in the extent of levamisole binding among species (ANOVA). Owing to the low degree of protein binding and the high volume of distribution of levamisole, the variations in protein binding due to different factors would not be of major clinical importance in its therapeutic application.