Search results for "PEG"
showing 10 items of 460 documents
Multicompartment Micelles with Adjustable Poly(ethylene glycol) Shell for Efficient in Vivo Photodynamic Therapy
2014
We describe the preparation of well-defined multicompartment micelles from polybutadiene-block-poly(1-methyl-2-vinyl pyridinium methyl sulfate)-block-poly(methacrylic acid) (BVqMAA) triblock terpolymers and their use as advanced drug delivery systems for photodynamic therapy (PDT). A porphyrazine derivative was incorporated into the hydrophobic core during self-assembly and served as a model drug and fluorescent probe at the same time. The initial micellar corona is formed by negatively charged PMAA and could be gradually changed to poly(ethylene glycol) (PEG) in a controlled fashion through interpolyelectrolyte complex formation of PMAA with positively charged poly(ethylene glycol)-block-p…
Gold nanostars coated with neutral and charged polyethylene glycols: A comparative study of in-vitro biocompatibility and of their interaction with S…
2015
Gold nanostars (GNS) have been coated with four different polyethylene glycols (PEGs) equipped with a -SH function for grafting on the gold surface. These PEGs have different chain lengths with average MW = 2000, 3000, 5000 and average number of -O-CH2-CH2 - units 44, 66, and 111, respectively. Two are neutral and two are terminated with -COOH and -NH2 functions, thus bearing negative and positive charges at physiological pH, thanks to the formation of carboxylate and ammonium groups. The negative charge of the GNS coated with PEG carboxylate has also been exploited to further coat the GNS with the PAH (polyallylamine hydrochloride) cationic polymer. Vitality tests have been carried out on …
Mucoadhesive PEGylated inulin-based self-assembling nanoparticles: In vitro and ex vivo transcorneal permeation enhancement of corticosteroids
2019
Abstract As transcorneal drug delivery is still a challenge, the scope of the present study was to prepare useful nanosystems able to enhance transcorneal permeation/penetration of drugs. Moreover, this work aims to evaluate the effectiveness of inulin-based nanosystems in the specific field of ocular drug delivery and the effect of PEG chains to promote mucoadhesion, stability and transcorneal penetration/permeation enhancer effect of self-assembling nanoparticles in vitro (transwell systems and HCE) and ex vivo (Franz cells and bovine cornea). In particular, inulin was chosen as the starting natural polysaccharide polymer to design a novel amphiphilic derivative named INU-EDA-RA-PEG capab…
PEGYLATED POLYASPARTAMIDE–POLYLACTIDE BASED NANOPARTICLES PENETRATING CYSTIC FIBROSIS ARTIFICIAL MUCUS
2016
Here, the preparation of mucus-penetrating nanoparticles for pulmonary administration of ibuprofen in patients with cystic fibrosis is described. A fluorescent derivative of α,β-poly(N-2-hydroxyethyl)-D,L-aspartamide is synthesized by derivatization with rhodamine, polylactide, and poly(ethylene glycol), to obtain polyaspartamide− polylactide derivatives with different degrees of pegylation. Starting from these copolymers, fluorescent nanoparticles with different poly(ethylene glycol) content, empty and loaded with ibuprofen, showed spherical shape, colloidal size, slightly negative ζ potential, and biocompatibility toward human bronchial epithelial cells. The high surface poly(ethylene gly…
Hyperbranched Polyols via Copolymerization of 1,2-Butylene Oxide and Glycidol: Comparison of Batch Synthesis and Slow Monomer Addition
2015
Hyperbranched poly(butylene oxide) polyols have been synthesized by multibranching anionic ring-opening copolymerization of 1,2-butylene oxide and glycidol. Systematic variation of the composition from 24 to 74% glycidol content resulted in a series of moderately distributed copolymers (Đ = 1.41–1.65, SEC), albeit with limited molecular weights in the solvent-free batch process in the range of 900–1300 g mol–1 (apparent Mn determined by SEC with PEG standards). In situ monitoring of the copolymerization kinetics by 1H NMR showed a pronounced compositional drift with respect to the monomer feed, indicating a strongly tapered microstructure caused by the higher reactivity of glycidol. In the …
Overcoming the PEG-addiction: well-defined alternatives to PEG from structure-property relationships to better defined therapeutics
2011
Synthetic methods in polymer chemistry have evolved tremendously during the last decade. Nowadays more and more attention is devoted to the application of those tools in the development of the next generation of nanomedicines. Nevertheless, poly(ethylene glycol) (PEG) remains the most frequently used polymer for biomedical applications. In this review, we try to summarize recent efforts and developments in controlled polymerisation techniques that may allow alternatives to PEG based systems and can be used to improve the properties of future polymer therapeutics.
Poly(methyl ethylene phosphate) hydrogels
2020
Abstract A degradable and water-soluble polyphosphoester (PPE), namely poly(methyl ethylene phosphate)-dimethacrylate (PMEP-DMA), was synthesized and crosslinked by UV irradiation to prepare PPE-hydrogels. Hydrogels with 10 and 15 wt% of PMEP were prepared after UV-irradiation with an additional 0.2 wt% of photoinitiator. The colorless and transparent PPE hydrogels were studied for their swelling and water uptake. The rheological analysis demonstrated their viscoelastic behavior. The PPE hydrogels were compared to poly(ethylene glycol) (PEG) hydrogels prepared from PEG-macromonomers of similar degrees of polymerization. Hydrolysis experiments proved a successful disintegration of the PPE hy…
"A versatile post-polymerization modification method for polyglutamic acid: synthesis of orthogonal reactive polyglutamates and their use in ""click …
2013
In this article we describe a versatile methodology for the synthesis of polyglutamic acid (PGA) derivatives bearing orthogonal reactive sites. The reactive groups enable selective conjugation chemistry by copper catalyzed azide-alkyne coupling (CuAAC). PGA was derived in aqueous media as well as in organic media using 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methyl morpholinium chloride (DMTTM) salts. The spectra of attached chemical moieties ranges from simple PEGylation with 2,5,8,11,14,17,20-heptaoxadocosan-22-amine (mEG(6)NH2) to the incorporation of propargylamine, 11-azido-3,6,9-trioxaundecan-1-amine (NH2-EG(2)N-3), and 20-azido-3,6,9,12,15,18-hexaoxaicosan-1-amine (NH2-EG(6)N-3). Here…
Universal Concept for the Implementation of a Single Cleavable Unit at Tunable Position in Functional Poly(ethylene glycol)s
2013
Poly(ethylene glycol) (PEG) with acid-sensitive moieties gained attention particularly for various biomedical applications, such as the covalent attachment of PEG (PEGylation) to protein therapeutics, the synthesis of stealth liposomes, and polymeric carriers for low-molecular-weight drugs. Cleavable PEGs are favored over their inert analogues because of superior pharmacodynamic and/or pharmacokinetic properties of their formulations. However, synthetic routes to acetal-containing PEGs published up to date either require enormous efforts or result in ill-defined materials with a lack of control over the molecular weight. Herein, we describe a novel methodology to implement a single acetalde…
Biodegradable pH-Sensitive Poly(ethylene glycol) Nanocarriers for Allergen Encapsulation and Controlled Release
2015
In the last decades, the number of allergic patients has increased dramatically. Allergen-specific immunotherapy (SIT) is the only available cause-oriented therapy so far. SIT reduces the allergic symptoms, but also exhibits some disadvantages; that is, it is a long-lasting procedure and severe side effects like anaphylactic shock can occur. In this work, we introduce a method to encapsulate allergens into nanoparticles to avoid severe side effects during SIT. Degradable nanocarriers combine the advantage of providing a physical barrier between the encapsulated cargo and the biological environment as well as responding to certain local stimuli (like pH) to release their cargo. This work int…