Ricerc@Sapienza

Polymer nanomaterials have received a great deal of interest as vehicles used for diagnostic and therapeutic agents [1]. The loading efficiency of a bile salt/block copolymer coformulation toward the fluorescent anticancer antibiotic doxorubicin has been studied. The coformulation is based on the anionic bile salt sodium cholate (NaC) and a nonionic triblock copolymer of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) denoted EO100-PO65-EO100 (F127) that itself forms micelles in water with a core composed mostly of PPO and a PEO corona. Doxorubicin is usually administered as the hydrochloride (DX) to increase its solubility in water. This limits its partitioning to the corona region of F127 micelles. To promote its solubility in the hydrophobic core, NaC was introduced in the system. The resulting systems obtained by varying the NaC/F127 mole ratio were characterized by small angle X-ray and dynamic light scattering (SAXS and DLS) in combination with spectroscopic fluorescence techniques (steady state and time-resolved). The host structure is not affected by the guest presence as deduced by SAXS and DLS data while in the presence of NaC, DX experiences a more apolar environment as indicated by its characteristic fluorescence behaviour (Figure 1). The stability against degradation of DX in the mixed micellar system was markedly enhanced relative to aqueous solutions without the coformulation [2]. The DX increased time stability in the NaC/pluronic mixed micellar systems is a promising characteristic that could lead to an increase of the drug latency and protection against hydrolytic degradation. In addition, the PEO hydrophilic corona could provide a certain level of biocompatibility and stealth characteristics to the mixed system, thus being attractive from an applicative point of view.