Search results for "Microsphere"
showing 10 items of 108 documents
Prostaglandin E(2)-loaded microspheres as strategy to inhibit phagocytosis and modulate inflammatory mediators release.
2008
PGE(2), an arachidonic acid metabolite produced by various type of cells regulates a broad range of physiological activities in the endocrine, cardiovascular, gastrointestinal, and immune systems, and is involved in maintaining the local homeostasis. In the immune system, PGE(2) is mainly produced by APCs and it can suppress the Th1-mediated immune responses. The aim of this study was to develop PGE(2)-loaded biodegradable MS that prolong and sustain the in vivo release of this mediator. An o/w emulsion solvent extraction-evaporation method was chosen to prepare the MS. We determined their diameters, evaluated the in vitro release of PGE(2), using enzyme immunoassay and MS uptake by periton…
Multilayer capsules: a promising microencapsulation system for transplantation of pancreatic islets
2001
In 1980, Lim and Sun introduced a microcapsule coated with an alginate/polylysine complex for encapsulation of pancreatic islets. Characteristic to this type of capsule is, that it consists of a plain membrane which is formed during a single procedural step. With such a simple process it is difficult to obtain instantly a membrane optimized with respect to all the properties requested for islet transplantation. To overcome these difficulties, it is recommended to build up the membrane in several consecutive steps, each optimized for a certain property. In this study, we have analysed such a multilayer microcapsule for the encapsulation of pancreatic islets. Therefore, empty and islet contai…
Vascular Endothelial Growth Factor-Releasing Microspheres Based on Poly(ε-Caprolactone-PEG-ε-Caprolactone)-b-Poly(L-Lactide) Multiblock Copolymers In…
2020
Pancreatic islet transplantation is a promising advanced therapy that has been used to treat patients suffering from diabetes type 1. Traditionally, pancreatic islets are infused via the portal vein, which is subsequently intended to engraft in the liver. Severe immunosuppressive treatments are necessary, however, to prevent rejection of the transplanted islets. Novel approaches therefore have focused on encapsulation of the islets in biomaterial implants which can protect the islets and offer an organ-like environment. Vascularization of the device’s surface is a prerequisite for the survival and proper func- tioning of transplanted pancreatic islets. We are pursuing a prevascularization s…
Hydroxypropyl Cellulose Films Filled with Halloysite Nanotubes/Wax Hybrid Microspheres
2021
The design of novel nanocomposite films based on hydroxypropyl cellulose (HPC) and wax/halloysite hybrid microspheres has been reported. In particular, we first prepared wax/clay Pickering emulsions which were characterized by thermogravimetric analysis and microscopy. SEM images allowed more detailed insights on the nanotubes disposition at the wax/water interface, acting as an outer stabilizing shell. Therefore, the cellulosic biopolymer was added, and it was found that HPC enhances the colloidal stability of the particles, preventing their coalescence and sedimentation. The preparation of the composite films was carried out by the solvent casting method, which enabled the development of …
Encapsulated Limonene: A Pleasant Lemon-Like Aroma with Promising Application in the Agri-Food Industry. A Review
2020
International audience; Limonene, mainly found as a major component in Citrus spp., has been proven to possess a valuable potential as sustainable replacement to synthetic pesticides and food preservatives. This review intends to give a clear overview of the principal emerging applications of limonene in the agri-food industry as antimicrobial, herbicidal and antioxidant agent. To successfully use limonene in a greener agri-food industry, its preservation had become a top concern for manufacturers. In order to elucidate the most efficient and sustainable manner to encapsulate limonene, the different techniques and materials tested up to the present are also reviewed. In general, encapsulati…
Synthetic/ECM-inspired hybrid platform for hollow microcarriers with ROS-triggered nanoporation hallmarks
2017
Reactive oxygen species (ROS) are key pathological signals expressed in inflammatory diseases such as cancer, ischemic conditions and atherosclerosis. An ideal drug delivery system should not only be responsive to these signals but also should not elicit an unfavourable host response. This study presents an innovative platform for drug delivery where a natural/synthetic composite system composed of collagen type I and a synthesized polythioether, ensures a dual stimuli-responsive behaviour. Collagen type I is an extracellular matrix constituent protein, responsive to matrix metalloproteinases (MMP) cleavage per se. Polythioethers are stable synthetic polymers characterized by the presence o…
Surface-Functionalized Latex Particles as Controlling Agents for the Mineralization of Zinc Oxide in Aqueous Medium
2005
Polystyrene latex particles modified at the surface with different hydrophilic functional groups were prepared by miniemulsion polymerization and used as controlling agents in the crystallization of zinc oxide from aqueous medium. The effects of the chemical nature of the surface functionalization and the latex concentration on the crystal growth, morphology, and crystalline structure of the resulting zinc oxide were analyzed. Micro- and submicrosized crystals with a broad variety of morphologies depending on the functionalization were obtained. Among the different latexes studied, the acrylic-acid-derived particles were shown to be a convenient system for further quantitative investigation…
Fast Response Heating Module for Temperature Programmed GC Analysis in Microreaction Systems
2000
For monitoring the reactant and product concentrations of a gas phase microreactor for ethylene oxide synthesis the development of a miniaturised device for fast GC analysis suitable for operation in conjunction with the microreactor is advantageous. Therefore, a method employing short (0.2 – 0.4 m) packed capillary columns was developed. Highly crosslinked polystyrene microspheres proved to be the most suitable adsorbent enabling a high separation efficiency. For fast temperature programming design concepts for an efficient heating module capable to be used with short capillary columns were developed. In principle, planar as well as cylindrical designs are suitable for integration of a res…
Ocular gelling microspheres: in vitro precorneal retention time and drug permeation through reconstituted corneal epithelium.
2008
Purpose: The model drug norfloxacin (NOR)was encapsulated into trehalose (TRH) and hydroxyethylcellulose(NAT) microspheres to obtain a novel gelling ophthalmic delivery system for prolonged release on corneal tissue. Methods: We assessed NOR release from microspheres, prepared by the emulsion-solvent evaporation method. A new in vitro tear turnover model, including inserts containing reconstituted human corneal epithelium (RHC), was designed to evaluate the TRH/NAT microspheres’ precorneal retention time. Bioadhesive properties of TRH/NAT microspheres were validated by using drug-loaded microspheres prepared with gelatine (GLT) commonly used as reference material in adhesion studies. Result…
Influence of low methoxyl pectin gel textures and in vitro release of rutin from calcium pectinate beads.
2013
This study described the preparation and characterization of low methoxyl pectin (LMP) gels and beads for controlled release applications. The rheological characterization of the various formulations was proposed. Then the mechanical and morphological characterizations of beads were determined. Finally, the controlled release studies taking rutin as a model drug was evaluated. The results showed that Young's modulus values of non-amidated LMP gels decrease when adding up to 15% sorbitol. Calcium pectinate beads loaded with rutin are about 600 μm, oblong shaped with dense matrix. Beads containing sodium bicarbonate showed about 80% lower rutin encapsulation efficiency by increasing the pH of…