Structural changes on polymeric nanoparticles induced by hydrophobic drug entrapment
Résumé
The potential use of polyester polymeric nanoparticles (NPs) as drug nanocarriers is well-documented.
Nevertheless, structural changes due to hydrophobic drug loading and release have been rarely explored. Herein,
we have used static and dynamic light scattering (SDLS), small-angle X-ray scattering (SAXS), transmission
electron microscopy (TEM) and cryo-TEM to probe how the entrapment of a hydrophobic drug molecule changes
the nanoparticles feature. The presence of the hydrophobic drug molecule modifies the inner structure of the
NPs. The polymeric assemblies are characterized by differences in their densities (∼0.06 g cm-3 for poly(D,Llactide)
– PLA or poly(D,L-lactide-co-glycolide – PLGA) and 0.46 g cm-3 for poly[(butylene succinate)-co-(butylene
dilinoleate)] − PBSBDL). They are thus water swollen in the drug-free condition. The NPs were further
prepared by using the same polyesters and given amounts of the poorly water-soluble drug paclitaxel (PTX). The
density (dNP), RG (radius of gyration), RH (hydrodynamic radius), RG/RH and R (contrast radius) have been
monitored as a function of the amount of drug loaded. The drug entrapment increased the size of PLA and PLGA
NPs. On the other hand, it also promoted the shrinkage of PBSBDL NPs. These observations revealed that changes
in the inner structure of soft nanoparticles caused by drug loading is not straightforward and it mainly depends