Search results for "Capsules"
showing 10 items of 103 documents
Mechanistic analysis and experimental verification of bicarbonate-controlled enteric coat dissolution: Potential in vivo implications
2019
Enteric coatings have shown in vivo dissolution rates that are poorly predicted by traditional in vitro tests, with the in vivo dissolution being considerably slower than in vitro. To provide a more mechanistic understanding of this, the dependence of the release properties of various enteric-coated (EC) products on bulk pH and bicarbonate molarity was investigated. It was found that, at presumably in vivo-relevant values, the bicarbonate molarity is a more significant determinant of the dissolution profile than the bulk pH. The findings also indicate that this steep relationship between the dissolution of enteric coatings and bicarbonate molarity limits those coatings' performance in vivo.…
Acetylcholinesterase-Capped Mesoporous Silica Nanoparticles That Open in the Presence of Diisopropylfluorophosphate (a Sarin or Soman Simulant)
2016
Mesoporous silica nanoparticles loaded with rhodamine B and capped with acetylcholinesterase are able to be selectively opened and deliver their cargo in the presence of nerve agent simulant diisopropyl fluorophosphate (DFP).
Mechanism of nanocapsules formation by the emulsion-diffusion process.
2007
International audience; A detailed investigation into the mechanisms of nanocapsule formation by means of the two stages “emulsion–diffusion” process is reported. Such widely used process is still poorly understood. An emulsion of oil, polymer and ethyl acetate is fabricated as a first step; dilution with pure water allows ethyl acetate to diffuse out from the droplets, leaving a suspension of nanocapsules at the end. It has been shown that the size of nanocapsules was related to the chemical composition of the organic phase and the size of primary emulsion through a simple geometrical relationship. As a consequence, most of the properties of the nanocapsules were decided at the emulsificat…
Biomolecular conjugation inside synthetic polymer nanopores via glycoprotein-lectin interactions
2011
We demonstrate the supramolecular bioconjugation of concanavalin A (Con A) protein with glycoenzyme horseradish peroxidase (HRP) inside single nanopores, fabricated in heavy ion tracked polymer membranes. Firstly, the HRP-enzyme was covalently immobilized on the inner wall of the pores using carbodiimide coupling chemistry. The immobilized HRP-enzyme molecules bear sugar (mannose) groups available for the binding of Con A protein. Secondly, the bioconjugation of Con A on the pore wall was achieved through its biospecific interactions with the mannose residues of the HRP enzyme. The immobilization of biomolecules inside the nanopore leads to the reduction of the available area for ionic tran…
Immunogenicity, reactogenicity and safety of a 7-valent pneumococcal conjugate vaccine (PCV7) concurrently administered with a DTPa-HBV-IPV/Hib combi…
2006
Abstract Background To evaluate immunogenicity, reactogenicity, and safety of a hexavalent combination vaccine diphtheria-tetanus-acellular pertussis-hepatitis B-inactivated polio virus- Haemophilus influenzae type b (DTPa-HBV-IPV/Hib) when coadministered with a 7-valent pneumococcal conjugate vaccine (PCV7). Methods Infants received either a hexavalent diphtheria-tetanus-acellular pertussis-hepatitis B-inactivated polio virus- H. influenzae type b vaccine concomitantly with PCV7 or DTPa-HBV-IPV/Hib alone infants were vaccinated at 2, 3 and 4 months (primary immunization) and 12–15 months of age (booster dose). Local and systemic reactions and adverse events were monitored following each do…
Nanoencapsulation in Lipid-Core Nanocapsules Controls Mometasone Furoate Skin Permeability Rate and Its Penetration to the Deeper Skin Layers
2013
<b><i>Aims:</i></b> The influence of nanoencapsulation of mometasone furoate (MF) in poly(ε-caprolactone) lipid-core nanocapsules (LNC) on its in vitro human skin permeation and penetration was evaluated. <b><i>Methods:</i></b> Semisolid formulations were prepared by increasing the viscosity of LNC using a carbomer (Carbopol® Ultrez at 0.5% w/v). Two complementary techniques (the static Franz diffusion cell model and the Saarbrücken penetration model) were used to evaluate skin permeation/penetration. <b><i>Results:</i></b> The drug release rate was decreased by nanoencapsulation. The skin permeability of MF was control…
Leach-Proof Sol–Gel Microcapsules as Curing Agents for One-Pot Thermosetting Resins
2013
The sol-gel microencapsulation of free-radical initiator benzoyl peroxide in sol-gel methyl-modified silica microcapsules of core/shell geometry allows curing of acrylate-based polyurethane and polyester resin formulations sprayed from a pressurized can without the need to compartmentalize reactants from the initiator to cross-link. These results open the route to widespread application of sol-gel microcapsules to efficiently cure polymer and composite mixtures that are widely used as functional coatings, molding compounds, adhesives, and sealants.
Polysaccharide-Based pH-Responsive Nanocapsules Prepared with Bio-Orthogonal Chemistry and Their Use as Responsive Delivery Systems.
2020
Bio-orthogonal reactions have become an essential tool to prepare biomaterials; for example, in the synthesis of nanocarriers, bio-orthogonal chemistry allows circumventing common obstacles related to the encapsulation of delicate payloads or the occurrence of uncontrolled side reactions, which significantly limit the range of potential payloads to encapsulate. Here, we report a new approach to prepare pH-responsive nanocarriers using dynamic bio-orthogonal chemistry. The reaction between a poly(hydrazide) crosslinker and functionalized polysaccharides was used to form a pH-responsive hydrazone network. The network formation occurred at the interface of aqueous nanodroplets in miniemulsion …
Heparin-Based Nanocapsules as Potential Drug Delivery Systems
2015
Herein, the synthesis and characterization of heparin-based nanocapsules (NCs) as potential drug delivery systems is described. For the synthesis of the heparin-based NCs, the versatile method of miniemulsion polymerization at the droplets interface was achieved resulting in narrowly distributed NCs with 180 nm in diameter. Scanning and transmission electron microscopy images showed clearly NC morphology. A highly negative charge density for the heparin-based NCs was determined by measuring the electro-kinetic potential. Measuring the activated clotting time demonstrated the biological intactness of the polymeric shell. The ability of heparin-based NCs to bind to antithrombin (AT III) was i…
Enhanced in vivo targeting of murine nonparenchymal liver cells with monophosphoryl lipid A functionalized microcapsules.
2014
A broad spectrum of infectious liver diseases emphasizes the need of microparticles for targeted delivery of immunomodulatory substances to the liver. Microcapsules (MCs) are particularly attractive for innovative drug and vaccine formulations, enabling the combination of antigen, drugs, and adjuvants. The present study aimed to develop microcapsules characterized by an enhanced liver deposition and accelerated uptake by nonparenchymal liver cells (NPCs). Initially, two formulations of biodegradable microcapsules were synthesized from either hydroxyethyl starch (HES) or mannose. Notably, HES-MCs accumulated primarily in the liver, while mannose particles displayed a lung preference. Functio…