Self-assembly study and formation of hydrophobized PVA dense and stable nanoparticles loaded with cholesterol or a steroid-type drug.

This work reports the preparation of modified poly(vinyl alcohol) PVA decorated with two different hydrophobic side-arms. Each material displays various percentages of pendant oleate and cholesteryl groups. The molar amount and the difference between their respective physico-chemical contributions are able to induce size variations of the formed micelles in aqueous media. These large amphiphilic structures hold a hydrophobic core ready for the incorporation of strong hydrophobic species such as cholesterol or prednisolone, a well-known low-water soluble steroid-type drug. In the presence of a steroid derivative, the modified PVA could form smaller and dense nanoparticles loaded in their cores. The synthesis of each polymer was controlled by (1)H NMR and FT-IR spectroscopies. The size of the empty micelles and the diameter of the loaded nanoparticles were determined by dynamic light scatting (DLS) studies. The measurement of the critical micelle concentration (CMC) was carried out for each polymer sample by fluorescence probing using pyrene. The amount of cholesterol incorporated into the hydrophobic core was estimated and all binding modes between the steroids and each amphiphilic polymer were also discussed in regard to their size distribution, concentration and stability.