Stability of fenbendazole suspensions for veterinary use. Correlation between zeta potential and sedimentation.
In this paper we have carried out a detailed investigation of the stability and redispersibility characteristics of fenbendazole aqueous suspensions, through a thermodynamic and electrokinetic characterization, considering the effect of both pH and ionic strength. The hydrophobic character of the drug, and the surface charge and electrical double-layer thickness play an essential role in the stability of the system, hence the need for a full characterization of fenbendazole. It was found that the drug suspensions displays "delayed" or "hindered" sedimentation, determined by their hydrophobic character and their low zeta potential (indicating a small electrokinetic charge on the particles). The electrostatic repulsion between the particles is responsible for the low sedimentation volume and poor redispersibility of the drug. However, only low concentrations of AlCl(3) induced a significant effect on both the zeta potential and stability of the drug, leading to a "free-layered" sedimentation and a very easy redispersion which could be of great interest in the design of an oral pharmaceutical dosage form for veterinary.
Arias
José L
JL
Department of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of Granada, Spain. jlarias@ugr.es
López-Viota
Margarita
M
Clares
Beatriz
B
Ruiz
Ma Adolfina
MA
D000284:Administration, Oral; D000077410:Aluminum Chloride; D017607:Aluminum Compounds / Q000737:chemistry; D000818:Animals; D000871:Anthelmintics / Q000008:administration & dosage / Q000737:chemistry*; D002626:Chemistry, Pharmaceutical; D002712:Chlorides / Q000737:chemistry; D004355:Drug Stability; D005273:Fenbendazole / Q000008:administration & dosage / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D009994:Osmolar Concentration; D010316:Particle Size; D055672:Static Electricity; D013499:Surface Properties; D013535:Suspensions; D013678:Technology, Pharmaceutical / Q000379:methods; D013816:Thermodynamics; D019155:Veterinary Drugs / Q000008:administration & dosage / Q000737:chemistry*
D017607:Aluminum Compounds; D000871:Anthelmintics; D002712:Chlorides; D013535:Suspensions; D019155:Veterinary Drugs; D000077410:Aluminum Chloride; D005273:Fenbendazole