8 research outputs found
Propaedeutic study for the delivery of nucleic acid-based molecules from PLGA microparticles and stearic acid nanoparticles
We studied the mechanism governing the delivery of nucleic acid-based drugs (NABD) from microparticles and nanoparticles in zero shear conditions, a situation occurring in applications such as in situ delivery to organ parenchyma. The delivery of a NABD molecule from poly(DL-lactide-co-glycolide) (PLGA) microparticles and stearic acid (SA) nanoparticles was studied using an experimental apparatus comprising a donor chamber separated from the receiver chamber by a synthetic membrane. A possible toxic effect on cell biology, as evaluated by studying cell proliferation, was also conducted for just PLGA microparticles. A mathematical model based on the hypothesis that NABD release from particles is due to particle erosion was used to interpret experimental release data. Despite zero shear conditions imposed in the donor chamber, particle erosion was the leading mechanism for NABD release from both PLGA microparticles and SA nanoparticles. PLGA microparticle erosion speed is one order of magnitude higher than that of competing to SA nanoparticles. Finally, no deleterious effects of PLGA microparticles on cell proliferation were detected. Thus, the data here reported can help optimize the delivery systems aimed at release of NABD from micro- and nanoparticles
Rheological properties of aqueous Pluronic-alginate systems containing liposomes
Rheological and erosion studies regarding a liposome-containing polymeric blend that is propaedeutic to its use in paving techniques in tubular
organs, such as blood vessels, are reported. Attention is focused on an aqueous polymeric blend composed of Pluronic (PF127) and alginate
(Protanal LF 10/60) because both polymers, when dissolved in water at a sufficiently high concentration, are subjected to different structural
mechanisms, which are driven by temperature increase and addition of bivalent cations, respectively, and both result in marked viscoelastic and
plastic properties. After proving the compatibility between PF127 and alginate, we show that the structural transition temperature of the blend,
TST, can be properly modulated. In particular, we found that TST for an aqueous solution of pure Pluronic 20% w/w is about 21 \u25e6C and that even
slight reductions in polymer concentration result in considerable TST decrease. The addition of salts or alginate (provided as Na-alginate) provokes
a substantial decrease of TST and thus the alginate concentration in the blend should not exceed 1% w/w. In addition, liposomes slow down the
structural transition but do not substantially affect the rheological properties of the system in the final state at higher temperatures, thus showing
that they can be added to the polymeric blend without significant effects. Finally, erosion tests show that after contact with a source of bivalent
cations, the polymeric blend containing PF127 and alginate shows an erosion resistance neatly improved with respect to the simple structured
Pluronic system having the same polymer concentration. As a whole, all these results constitute the basis for future potential applications of the
considered polymeric blend in tubular organs such as blood vessels
Characterisation of liposomes for the delivery of siRNAs in the treatment of coronary restenosis
9nonenoneR Farra ; D Voinovich ; F Rubessa ; R Lapasin ; M Grassi ; G Guarnieri; A Pascotto; B Rehimers; G GrassiFarra, Rossella; Voinovich, Dario; F., Rubessa; Lapasin, Romano; Grassi, Mario; Guarnieri, Gianfranco; A., Pascotto; B., Rehimers; Grassi, Gabriel