Turbiscan Lab ® Expert analysis of the stability of ethosomes ® and ultradeformable liposomes containing a bilayer fluidizing agent

Abstract

The stability of vesicular drug carriers containing linoleic acid, as a model of bilayer fluidizing agent, was evaluated using a Turbiscan optical analyzer, an innovative analytical instrument able to determine the long-time stability of colloidal systems. Ethosomes ® and ultradeformable liposomes were prepared using Phospholipon 100G ® as the lecithin component, while ethanol and sodium cholate were used for the specific preparation of ethosomes ® and ultradeformable liposomes, respectively. The advantages of the Turbiscan optical analyzer are: (i) its ability to measure reversible (creaming and sedimentation) and irreversible (coalescence and segregation) destabilization phenomena directly in the sample without any dilution and (ii) to detect these phenomena much earlier and easier than other apparatuses. Turbiscan data showed that both colloidal vesicles demonstrate a good stability during the 3 h of the experiment. No modification of Turbiscan backscattering profiles of colloidal suspensions occurred when different amounts of linoleic acid were used to prepare ethosomes ® and ultradeformable liposomes. No coalescence, sedimentation, flocculation or clarification occurred. The results were very encouraging and confirmed the fact that the Turbiscan optical analyzer can be used to study the stability of colloidal formulations even in the presence of deformable agents.