Journal of Colloid and Interface Science, Vol.382, 36-47, 2012
Retinyl palmitate polymeric nanocapsules as carriers of bioactives
Nanocapsules containing poly(D,L-lactide) shell and retinyl palmitate core have been prepared by the preformed polymer interfacial deposition method. Dynamic light scattering measurements yielded an average hydrodynamic diameter of similar to 220 nm and a polydispersity index of similar to 0.12. Small-angle neutron scattering experiments revealed the presence of two populations of nanocapsules of core diameters similar to 192 and 65 nm. Freeze fracture transmission electron microscopy showed a polydisperse population of nanocapsules (NC), with a poly(D,L-lactide) shell thickness between 11 and 3 nm. For comparison purposes, nanoemulsions (NE, no polymer) and nanospheres (NS, polymer matrix) were also prepared. Each type of nanoparticles exhibited a different morphology (when examined by electron microscopy), in particular NC showed deformability by capillary adhesion. All three types of nanoparticles successfully encapsulated the poorly water-soluble molecules baicalein and benzophenone-3. The thermal behavior of the various nanoparticles was different to a physical mixture of its individual components. Cytotoxicity and phototoxicity assays, performed in human keratinocytes (HaCaT) and murine fibroblasts (BALB/c3T3), showed that the NC were only cytotoxic at high concentrations. In vitro release studies of benzophenone-3, by the dialysis bag method using NC and NS, showed a sustained release; however, permeation studies using plastic surgery human abdominal skin in Franz diffusion cells showed that a higher amount of benzophenone-3 from NC penetrated into the skin, most probably due to the deformable nature of these nanoparticles. (C) 2012 Elsevier Inc. All rights reserved.
Keywords:Polymeric nanoparticles;Poly(D,L-lactide);Nanocapsules;Skin permeation;Phototoxicity;Cytotoxicity;Small-angle neutron scattering