Search results for "Pluronic"
showing 6 items of 6 documents
Dispersions of nanosilica in biocompatible copolymers
2010
Dispersions of nanosilica in matrices of biocompatible copolymers were prepared by melt blending. Copolymers with variable molecular size at fixed hydrophilic/hydrophobic ratio and nanosilicas with different interfacial areas were studied. For comparison, a nanoclay was also investigated. The interfacial area played a relevant role in conferring peculiar properties on the nanohybrids. Amazingly, the macromolecule adsorbed on the nanosilica surface maintains some crystallinity which was quantitatively evaluated. In contrast, all the macromolecule anchored to the nanoclay surface is amorphous. The change of the crystalline state was reflected in the dielectric and the electrical conductivity …
Poloxamer/sodium cholate co-formulation for micellar encapsulation of Doxorubicin with high efficiency for intracellular delivery: an in-vitro bioava…
2020
Abstract Hypothesis Doxorubicin hydrochloride (DX) is widely used as a chemotherapeutic agent, though its severe side-effects limit its clinical use. A way to overcome these limitations is to increase DX latency through encapsulation in suitable carriers. However, DX has a high solubility in water, hindering encapsulation. The formulation of DX with sodium cholate (NaC) will reduce aqueous solubility through charge neutralization and hydrophobic interactions thus facilitating DX encapsulation into poloxamer (F127) micelles, increasing drug latency. Experiments DX/NaC/PEO-PPO-PEO triblock copolymer (F127) formulations with high DX content (DX-PMs) have been prepared and characterized by scat…
Temperature and concentration effects on supramolecular aggregation and phase behavior for poly(propylene oxide)–b-poly(ethylene oxide) –b-poly(propy…
2011
The micro- and mesoscopic structure of reverse Pluronic 25R4 in aqueous mixtures has been studied by SANS, SAXS and shear rheology. These techniques have been able to give a deep insight into the complex structure of the system phase diagram, that includes an isotropic water-rich liquid phase L(1), and liquid crystalline phases with hexagonal, E, or lamellar order, D. Particular attention has been paid to the isotropic water-rich phase L(1), which has a large stability region in the temperature-composition phase diagram. This region is crossed by a large "cloudy zone". Below it, namely at low temperature and composition, SANS data show the presence of polymer unimers in a gaussian coil conf…
A fluorescence study of the loading and time stability of doxorubicin in sodium cholate/PEO-PPO-PEO triblock copolymer mixed micelles
2019
Abstract Hypothesis Doxorubicin hydrochloride (DX) is one of the most powerful anticancer agents though its clinical use is impaired by severe undesired side effects. DX encapsulation in nanocarrier systems has been introduced as a mean to reduce its toxicity. Micelles of the nonionic triblock copolymers of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) (PEO-PPO-PEO), are very promising carrier systems. The positive charge of DX confines the drug to the hydrophilic corona region of the micelles. The use of mixed micelles of PEO-PPO-PEO copolymers and a negatively charged bile salt should favour the solubilization of DX in the apolar core region of the micelles. Experiments We st…
Physical characterization of alginate-Pluronic F127 gel for endoluminal NABDs delivery
2014
Here we focus the attention on the physical characteristics of a highly biocompatible hydrogel made up of crosslinked alginate and Pluronic F127 (PF127). This is a composite polymeric blend we propose for artery endoluminal delivery of an emerging class of molecules named nucleic acid based drugs (NABDs). The physical characterization of our composite gel, i.e. mesh size distribution and PF127-alginate mutual organization after crosslinking, can significantly determine the NABDs release kinetics. Thus, to explore these aspects, different technical approaches, i.e. rheology, low/high field NMR and TEM, were used. While rheology provided information at the macroscopic and nano-level, the othe…
Halloysite nanotubes/pluronic nanocomposites for waterlogged archeological wood: thermal stability and X-ray microtomography
2020
Filling a polymer with halloysite nanotubes is considered a promising strategy to generate nanocomposites with tailored physicochemical properties. We have focused our attention on pluronic block copolymer/halloysite nanocomposites prepared by melt blending. The effect of composition on thermal stability and polymer crystallinity was investigated by thermogravimetry and differential scanning calorimetry. Electron microscopy was used to monitor the nanoparticle distribution in the polymeric matrix. The pluronic thermal stability is reduced by the clay nanoparticles. Concerning the polymer crystallinity, it is slightly decreased even if the melting temperature is lowered by halloysite. Furthe…