Search results for "Polylactic Acid-Polyglycolic Acid Copolymer"
showing 9 items of 19 documents
Ion-pair approach coupled with nanoparticle formation to increase bioavailability of a low permeability charged drug.
2018
Abstract Atenolol is a drug widely used for the treatment of hypertension. However, the great drawback it presents is a low bioavailability after oral administration. To obtain formulations that allow to improve the bioavailability of this drug is a challenge for the pharmaceutical technology. The objective of this work was to increase the rate and extent of intestinal absorption of atenolol as model of a low permeability drug, developing a double technology strategy. To increase atenolol permeability an ion pair with brilliant blue was designed and the sustained release achieved through encapsulation in polymeric nanoparticles (NPs). The in vitro release studies showed a pH-dependent relea…
Nanoparticle formulations as recrystallization inhibitors in transdermal patches
2020
Abstract Drug crystallization in transdermal patches is still a major challenge, confronting the formulation development of topical drug delivery systems. Encapsulation of drugs into nanoparticles is proposed here as a promising tool for regulating drug crystallization in transdermal patches. The degree of recrystallization and transdermal permeation of ibuprofen and hydrocortisone loaded in polymeric and lipid nanoparticles from matrix-type transdermal patches were investigated. Ethyl cellulose (EC4), poly (lactide-co-glycolic acid) (PLGA) and polycaprolactone (PCL) were employed for polymeric nanoparticle preparations; while medium chain triglyceride (MCT) and witepsol were used for the p…
Compromised integrity of excised porcine intestinal epithelium obtained from the abattoir affects the outcome of in vitro particle uptake studies
2002
Excised porcine intestinal tissue obtained from the local abattoir was studied for its suitability to examine the uptake and transport of poly(lactic-co-glycolic acid) (PLGA) nanoparticles in Peyer's (PP) and non-Peyer's patch (NPP) tissue in vitro. Incubation of such tissue with fluorescent PLGA and polystyrene particles revealed negligible uptake into the intercellular space with no noticeable difference between PP and NPP tissue. Similarly, yeast cells, which were used as a positive control for selective uptake into PP tissue, were found in the subepithelial area of both PP and NPP tissue. Therefore we examined the morphological integrity of the tissue for the duration of the experiments…
Local Delivery of Nimodipine by Prolonged-Release Microparticles—Feasibility, Effectiveness and Dose-Finding in Experimental Subarachnoid Hemorrhage
2012
Background and purposeTo investigate the effect of locally applied nimodipine prolonged-release microparticles on angiographic vasospasm and secondary brain injury after experimental subarachnoid hemorrhage (SAH).Methods70 male Wistar rats were categorized into three groups: 1) sham operated animals (control), 2) animals with SAH only (control) and the 3) treatment group. SAH was induced using the double hemorrhage model. The treatment group received different concentrations (20%, 30% or 40%) of nimodipine microparticles. Angiographic vasospasm was assessed 5 days later using digital subtraction angiography (DSA). Histological analysis of frozen sections was performed using H&E-staining as …
?Reliability of new poly (lactic-co-glycolic acid) membranes treated with oxygen plasma plus silicon dioxide layers for pre-prosthetic guided bone re…
2017
Background: The use of cold plasmas may improve the surface roughness of poly(lactic-co-glycolic) acid (PLGA) membranes, which may stimulate the adhesion of osteogenic mediators and cells, thus accelerating the biodegradation of the barriers. Moreover, the incorporation of metallic-oxide particles to the surface of these membranes may enhance their osteoinductive capacity. Therefore, the aim of this paper was to evaluate the reliability of a new PLGA membrane after being treated with oxygen plasma (PO) plus silicon dioxide (SiO) layers for guided bone regeneration (GBR) processes. Material and Methods: Circumferential bone defects (diameter: 11 mm; depth: 3 mm) were created on the top of ei…
Emulsion-based synthesis of PLGA-microspheres for the in vitro expansion of porcine chondrocytes.
2007
Abstract The in vitro cell expansion of autologous chondrocytes is of high interest in regenerative medicine since these cells can be used to treat joint cartilage defects. In order to preserve chondrocyte phenotype, while optimizing adhesion on microspheres, several processing parameters for the microsphere synthesis were varied. In this study three different polylactide-co-glycolides were used with differing lactide–glycolide ratios (85:15 and 50:50) and differing inherent viscosities. An emulsion route was established, where the polymer was dissolved in chloroform and then injected into a stirred polyvinyl alcohol–water solution at different polymer concentrations and different stirring …
Dexamethasone dipropionate loaded nanoparticles of α-elastin-g-PLGA for potential treatment of restenosis.
2013
A graft copolymer of α-elastin with poly(lactic-co-glycolic) acid (PLGA) has been synthesized and successfully employed to produce nanoparticles. Exploiting the known biological activity of α-elastin to promote the maintenance of smooth muscle cells (SMCs) contractile phenotype and the antiproliferative effect of glucocorticoids, the aim of this research was to produce drug-loaded nanoparticles suitable for potential treatment of restenosis. In particular, nanoparticles of α-elastin-g-PLGA with a mean size of 200 nm have been produced and loaded with dexamethasone dipropionate (10% w/w), chosen as a model drug that inhibits proliferation of vascular SMCs. These nanoparticles are able to pro…
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…
"Click" on PLGA-PEG and hyaluronic acid: gaining access to anti-leishmanial pentamidine bioconjugates
2018
Pentamidine (Pent), an antiparasitic drug used for the treatment of visceral leishmaniasis, has been modified with terminal azide groups and conjugated to two different polymer backbones (PLGA-PEG [PP] copolymer and hyaluronic acid [HA]) armed with alkyne end-groups. The conjugation has been performed by Copper Catalyzed Azido Alkyne Cycloaddition (CuAAC) using CuSO4/sodium ascorbate as metal source. The novel PP-Pent and HA-Pent bioconjugates are proposed, respectively, as non-targeted and targeted drug delivery systems against Leishmania infections. Moreover, Pent has been encapsulated into PP nanoparticles by the oil-in-water emulsion method, with the aim to compare the biological activi…