The therapeutic effect is caused by the inhibition of the protein aggregation in the affected tissue, such as the brain. 3, 5-Diphenyl-diazole derivatives have been shown to be effective in inhibiting aggregation of proteins but are also characterized by their poor solubility in aqueous solutions. The prodrugs of the invention are modified 3, 5-diphenyl-diazole derivatives, which are characterized by their improved solubility in aqueous solutions, and by their increased bioavailability.