Search results for "Poly(lactic acid)"
showing 10 items of 91 documents
Microparticle preparation by a propylene carbonate emulsification-extraction method
2018
Abstract The use of various harmful organic solvents for microparticle formulations is still widespread. Here, an alternative low toxicity solvent (propylene carbonate; PC) is proposed for the preparation of poly(lactic-co-glycolic-acid) (PLGA) microparticles. Based on the classical emulsification-solvent extraction methodology, the use of PC offers the unique advantage of an additional solvent extraction step using hydrolytic solvent cleavage during microparticle preparation. Spherical, rough-surfaced microparticles were obtained with a volume median diameter range from 20 to 60 µm. The residual PC content has been identified to be the major factor for the solidification hindrance, leading…
Polyaspartamide-polylactide electrospun scaffolds for potential topical release of Ibuprofen.
2012
In this work, the production and characterization of electrospun scaffolds of the copolymer α,β-poly(N-2-hydroxyethyl)-DL-aspartamide-graft-polylactic acid (PHEA-g-PLA), proposed for a potential topical release of Ibuprofen (IBU), are reported. The drug has been chemically linked to PHEA-g-PLA and/or physically mixed to the copolymer before electrospinning. Degradation studies have been performed as a function of time in Dulbecco phosphate buffer solution pH 7.4, for both unloaded and drug-loaded scaffolds. By using an appropriate ratio between drug physically blended to the copolymer and drug-copolymer conjugate, a useful control of its release can be obtained. MTS assay on human dermal fi…
Advanced descriptors for long-range noncovalent interactions between SARS-CoV-2 spikes and polymer surfaces.
2021
The recent pandemic triggered numerous societal efforts aimed to control and limit the spread of SARS-CoV-2. One of these aspects is related on how the virion interacts with inanimate surfaces, which might be the source of secondary infection. Although recent works address the adsorption of the spike protein on surfaces, there is no information concerning the long-range interactions between spike and surfaces, experimented by the virion when is dispersed in the droplet before its possible adsorption. Some descriptors, namely the interaction potentials per single protein and global potentials, were calculated in this work. These descriptors, evaluated for the closed and open states of the sp…
Galactosylated micelles for a ribavirin prodrug targeting to hepatocytes.
2013
Polymeric micelles potentially able to carry to hepatocytes a ribavirin (RBV) prodrug, exploiting the presence of carbohydrate receptors, that is, ASGPR, were prepared starting from a galactosylated polylactide-polyaminoacid conjugate. This latter was obtained by chemical reaction of α,β-poly(N-2-hydroxyethyl) (2-aminoethylcarbamate)-dl-aspartamide (PHEA-EDA) with polylactic acid (PLA), and subsequent reaction with lactose, obtaining PHEA-EDA-PLA-GAL copolymer. To enhance the entrapment into obtained nanostructures, a hydrophobic RBV prodrug, that is, RBV tripalmitate, was synthesized and its capability to release RBV in the presence of an adequate enzymatic activity was demonstrated. Liver…
Evaluation of biodegradability on polyaspartamide-polylactic acid based nanoparticles by chemical hydrolysis studies
2015
Here, the synthesis of two graft copolymers based on ?,?-poly(N-2-hydroxyethyl)-D,L-aspartamide (PHEA) and poly(lactic acid) (PLA), the O-(2-aminoethyl)-O'-galactosyl polyethylene glycol (GAL-PEG-NH2) or the methoxypolyethylene glycol amine (H2N-PEG-OCH3) is described. Starting from the obtained PHEA-PLA-PEG-GAL and PHEA-PLA-PEG copolymers, polymeric nanoparticles were prepared by high pressure homogenization-solvent evaporation method. To demonstrate their biodegradability as a function of the matrix composition, a chemical stability study was carried out until 21 days by incubating systems in two media mimicking physiological compartments (pH 7.4 and pH 5.5). The degradability of both nan…
Plasma modified PLA electrospun membranes for actinorhodin production intensification in Streptomyces coelicolor immobilized-cell cultivations
2017
Most of industrially relevant bioproducts are produced by submerged cultivations of actinomycetes. The immobilization of these Gram-positive filamentous bacteria on suitable porous supports may prevent mycelial cell-cell aggregation and pellet formation which usually negatively affect actinomycete submerged cultivations, thus, resulting in an improved biosynthetic capability. In this work, electrospun polylactic acid (PLA) membranes, subjected or not to O2-plasma treatment (PLA-plasma), were used as support for immobilized-cell submerged cultivations of Streptomyces coelicolor M145. This strain produces different bioactive compounds, including the blue-pigmented actinorhodin (ACT) and red-p…
Model predictive control for continuous lactide ring‐opening polymerization processes
2020
International audience; Polylactic acid (PLA) is an attractive environment-friendly thermoplastic that is bio-sourced and biodegradable. PLA is industrially produced by the ring-opening polymerization of Lactide. This reaction is sensitive to drifts in the operating conditions and impurities in the raw materials that may affect the reaction rate as well as the polymer properties, which can be very costly in continuous processes. It is therefore crucial to employ a control strategy that allows recovering the nominal conditions and maintaining the desired properties and conversion level in case of drift. Three control strategies are discussed in this paper: Proportional-Integral controller (P…
POLYASPARTAMIDE-POLYLACTIDE GRAFT COPOLYMERS WITH TUNABLE PROPERTIES FOR THE REALIZATION OF FLUORESCENT NANOPARTICLES FOR IMAGING
2015
Here, the synthesis and the characterization of novel amphiphilic graft copolymers with tunable properties, useful in obtaining polymeric fluorescent nanoparticles for application in imaging, are described. These copolymers are obtained by chemical conjugation of rhodamine B (RhB) moieties, polylactic acid (PLA), and O-(2-aminoethyl)-O'-methyl poly(ethylene glycol) (PEG) on α,β-poly(N-2-hydroxyethyl)-D,L-aspartamide (PHEA). In particular, PHEA is first functionalized with RhB to obtain PHEA-RhB with a derivatization degree in RhB (DDRhB ) equal to 0.55 mol%. By varying the reaction conditions, different amounts of PLA are grafted on PHEA-RhB to obtain PHEA-RhB-PLA with DDPLA equal to 1.9, 4…
Uptake of polymeric nanoparticles in a human induced pluripotent stem cell-based blood-brain barrier model: Impact of size, material, and protein cor…
2021
The blood–brain barrier (BBB) maintains the homeostasis of the central nervous system, which is one of the reasons for the treatments of brain disorders being challenging in nature. Nanoparticles (NPs) have been seen as potential drug delivery systems to the brain overcoming the tight barrier of endothelial cells. Using a BBB model system based on human induced pluripotent stem cells (iPSCs), the impact of polymeric nanoparticles has been studied in relation to nanoparticle size, material, and protein corona. PLGA [poly(lactic-co-glycolic acid)] and PLLA [poly(d,l-lactide)] nanoparticles stabilized with Tween® 80 were synthesized (50 and 100 nm). iPSCs were differentiated into human brain m…
Targeted delivery of Cyclosporine A by polymeric nanocarriers improves the therapy of inflammatory bowel disease in a relevant mouse model
2017
The therapy of inflammatory bowel diseases is still rather inefficient, and about 80% of patients require surgery at some stage. Improving the treatments by more efficient medication is, therefore, an urgent medical need. The objective of this project was to demonstrate targeted delivery of Cyclosporine-A (CYA) to the inflamed areas of the intestinal mucosa after oral administration, enabling improved alleviation of the symptoms and, at the same time, reduced systemic drug absorption and associated adverse effects. As had already been demonstrated in previous studies, nano- to micrometer-sized drug particles will accumulate at inflamed mucosal areas, providing a platform for such purposes. …