Search results for "Polymethacrylic Acids"
showing 10 items of 29 documents
Nanoparticles of a polyaspartamide-based brush copolymer for modified release of sorafenib: In vitro and in vivo evaluation.
2017
Abstract In this paper, we describe the preparation of polymeric nanoparticles (NPs) loaded with sorafenib for the treatment of hepatocellular carcinoma (HCC). A synthetic brush copolymer, named PHEA-BIB-ButMA (PBB), was synthesized by Atom Trasnfer Radical Polymerization (ATRP) starting from the α-poly( N -2-hydroxyethyl)- d , l -aspartamide (PHEA) and poly butyl methacrylate (ButMA). Empty and sorafenib loaded PBB NPs were, then, produced by using a dialysis method and showed spherical morphology, colloidal size, negative ζ potential and the ability to allow a sustained sorafenib release in physiological environment. Sorafenib loaded PBB NPs were tested in vitro on HCC cells in order to e…
PHEA-graft-polymethacrylate supramolecular aggregates for protein oral delivery
2013
Abstract Salmon calcitonin (sCT) is characterized by a poor oral availability. A new copolymer, β-poly(N-2-hydroxyethyl)-graft-{N-2-ethylene[2-poly(methacrylic acid sodium salt)isobutyrate]}- d , l -aspartamide (PHEA-IB-p(MANa + )), was designed for the oral administration of sCT through the formation of supramolecular aggregates (SAs) based on electrostatic interactions. Several sCT/PHEA-IB-p(MANa + ) weight ratios were characterized by turbidimetry, DLS, zeta potential, and microscopy analysis. After the incubation of sCT/PHEA-IB-p(MANa + ) complex with digestive enzymes, 10% (w/w) of loaded sCT was released in the native form. In vitro investigation was carried out to determine the copol…
Erzeugung von Sarkomen durch Fremdkörper aus Polymethacrylaten und Zusätzen
1962
Es wird uber die cancerogene Wirkung von Plattchen aus verschiedenen Kunststoffen berichtet (s. Tabelle).
Effect of cyclic loading on fracture strength and microleakage of a quartz fiber dowel with different adhesive, cement and resin core material combin…
2010
Background: This study evaluated the performance of different adhesive-cement-core combinations coupled with quartz fiber dowels after cyclic loading and fracture strength tests and assessed the microleakage using dye penetration method. Methods: Forty maxillary canines (n=10 per group) were restored with fiber dowels (Quartz fiber DT Light Post) and four adhesive-cement-core material combinations [(Group 1: All-Bond 2+C&B (root) / All-Bond 2+Biscore (core); Group 2: All-Bond 2+Bisfil 2B (root) / All-Bond 2+Bisfil 2B (core); Group 3: Scotchbond 1+RelyX ARC (root) / Scotchbond 1+Supreme (core); Group 4: RelyX Unicem (root) / Scotchbond 1+Filtek Supreme (core)]. The specimens were initially c…
Polymeric microcontainers improve oral bioavailability of furosemide.
2016
Microcontainers with an inner diameter of 223 μm are fabricated using the polymer SU-8, and evaluated in vitro, in situ and in vivo for their application as an advanced oral drug delivery system for the poorly water soluble drug furosemide. An amorphous sodium salt of furosemide (ASSF) is filled into the microcontainers followed by applying a lid using Eudragit L100. It is possible to control the drug release in vitro, and in vitro absorption studies show that the microcontainers are not a hindrance for absorption of ASSF. In situ perfusion studies in rats are performed with ASSF-filled microcontainers coated with Eudragit and compared to a furosemide solution. The absorption rate constant …
Histidine-rich glycoprotein-induced vascular normalization improves EPR-mediated drug targeting to and into tumors
2018
Tumors are characterized by leaky blood vessels, and by an abnormal and heterogeneous vascular network. These pathophysiological characteristics contribute to the enhanced permeability and retention (EPR) effect, which is one of the key rationales for developing tumor-targeted drug delivery systems. Vessel abnormality and heterogeneity, however, which typically result from excessive pro-angiogenic signaling, can also hinder efficient drug delivery to and into tumors. Using histidine-rich glycoprotein (HRG) knockout and wild type mice, and HRG-overexpressing and normal t241 fibrosarcoma cells, we evaluated the effect of genetically induced and macrophage-mediated vascular normalization on th…
Polymethacrylate monoliths with immobilized poly-3-mercaptopropyl methylsiloxane film for high-coverage surface functionalization by thiol-ene click …
2014
In this work, new polythiol-functionalized macroporous monolithic polymethacrylate-polysiloxane composite materials are presented which can be useful substrates for highly efficient immobilization of (chiral) catalysts, chromatographic ligands, and other functional moieties by thiol-ene click reaction. Poly(glycidyl methacrylate-co-ethylene dimethacrylate) (poly(GMA-co-EDMA)) monoliths were coated with a poly-3-mercaptopropyl methylsiloxane (PMPMS) film and subsequently the polymer was covalently immobilized by formation of crosslinks via nucleophilic substitution reaction with pendent 2,3-epoxypropyl groups on the monolith surface. This monolith, though, showed similar levels of surface co…
HPMA-LMA copolymer drug carriers in oncology: an in vivo PET study to assess the tumor line-specific polymer uptake and body distribution.
2013
Polymeric drug carriers aim to selectively target tumors in combination with protecting normal tissue. In this regard polymer structure and molecular weight are key factors considering organ distribution and tumor accumulation of the polymeric drug delivery system. Four different HPMA based copolymer structures (random as well as block copolymers with lauryl methacrylate as hydrophobic block) varying in molecular weight, size and resulting architecture were analyzed in two different tumor models (AT1 prostate carcinoma and Walker-256 mammary carcinoma) in vivo. Polymers were labeled with (18)F and organ/tumor uptake was followed by μPET imaging and ex vivo biodistribution. Vascular permeabi…
Freeze-dried eudragit-hyaluronan multicompartment liposomes to improve the intestinal bioavailability of curcumin.
2016
This work aimed at finding an innovative vesicle-type formulation able to improve the bioavailability of curcumin upon oral administration. To this purpose, phospholipid, Eudragit® S100 and hyaluronan sodium salt were combined to obtain eudragit-hyaluronan immobilized vesicles using an easy and environmentally-friendly method. For the first time, the two polymers were combined in a system intended for oral delivery, to enhance curcumin stability when facing the harsh environment of the gastrointestinal tract. Four different formulations were prepared, keeping constant the amount of the phospholipid and varying the eudragit-hyaluronan ratio. The freeze-drying of the samples, performed to inc…
Improvement of the butyl methacrylate-paraffin embedment.
1983
The excellent butyl methacrylate-paraffin method as an embedment for light microscopy has been technically improved. More uniform and reproducible polymerization has been obtained by using a vacuum oven to degas the polymerizing mixture and to replace the air with nitrogen at 650 Torr. The amount of benzoyl peroxide required must be determined for each batch of butyl methacrylate. A teflon lined, reusable metal mold and a method of one-step blocking of tissues in preparation for sectioning are also described.