Influence of Poloxamer 407 on Surface Properties of Aqueous Solutions of Polysorbate Surfactants

Owing to their ability to adsorb at interfaces, polysorbates have an important role in pharmaceutical formulations. Because surfactant mixtures can have improved properties, it was hypothesized in this work that introduction of poloxamer 407 to aqueous solutions of polysorbates (polysorbate 60, polysorbate 80 and polysorbate 85) might improve their surface properties. Nonideal behavior of surfactant mixtures at the air/water interface was investigated using Rosen's model and recently introduced method for the determination and quantification of nonideal behavior regarding surface tension reduction and adsorption effectiveness. Although nonideal behavior was noticed in all mixed monolayers, it was shown that the structure of the hydrophobic domain of the polysorbates and the conformation of poloxamer 407 at the interface have strong influence on the nonideality.