Role of the electrokinetic properties on the stability of mebendazole suspensions for veterinary applications.

This work is focused on the analysis of the effect of basic physicochemical aspects (surface thermodynamic and electrokinetic characteristics) on the stability and redispersibility properties of mebendazole aqueous suspensions. To our knowledge, previous investigations on the formulation of mebendazole suspensions have been not devoted to the elucidation of the colloidal behavior of this benzimidazole carbamate. A deep thermodynamic and electrokinetic characterization, considering the effect of both pH and ionic strength, was carried out with that purpose. It was found that the hydrophobicity and, the surface charge and electrical double layer thickness of the drug play a significant role in the stability of the colloid. Mebendazole aqueous suspensions display a controllable "delayed" or "hindered" sedimentation and a very easy redispersion which may contribute to the formulation of veterinary liquid dosage forms.