Novel biomimetic systems based on polyethylene glycols and amphiphilic phosphonium salt. Self-organization and solubilization of hydrophobic guest

The solution behavior of single and binary systems based on biorelevant building blocks, i.e., polyethylene glycol (PEG) of different molecular weight, and a cationic surfactant, cetyltriphenylphosphonium bromide (TPPB), has been studied. Tensiometry data for PEG–water solutions provide critical aggregation concentrations which decrease with an increase of molecular weight of the polymer. Large particles of ⩾200 nm occur in the PEG-1000 solution along with the smaller ones, while in the PEG-400 and PEG-20000 samples only populations coinciding with the size of the polymer coils are found. The dye solubilization study reveals that some hydrophobic domains occur in the PEG solution. The binary PEG-TPPB systems demonstrate a synergetic behavior, i.e. a decrease in critical micelle concentration and much higher solubilization power as compared to single TPPB micelles. The data obtained reveal that PEG-TPPB assemblies present soft nanocontainers, which (i) are composed of biorelevant components; (ii) are formed at low concentrations; (iii) are characterized by nanoscale dimension; (iv) exhibit high binding capacity toward water insoluble guest. Based on these features they may be considered as candidates for the drug delivery formulations.