Universities of Kent Greenwich

Kings Hill, United Kingdom

Universities of Kent Greenwich

Kings Hill, United Kingdom
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Thomas M.J.K.,University of Greenwich | Slipper I.,University of Greenwich | Walunj A.,University of Greenwich | Jain A.,University of Greenwich | And 3 more authors.
International Journal of Pharmaceutics | Year: 2010

Silica nanoparticles (MSNs) with a highly ordered mesoporous structures (103Å) with cubic Im3̄m have been synthesized using triblock copolymers with high poly(alkylene oxide) (EO) segments in acid media. The produced nanoparticles displayed large specific surface area (∼765cm2/g) with an average particles size of 120nm. The loading efficiency was assessed by incorporating three major antiepileptic active substances via passive loading and it was found to varying from 17 to 25%. The state of the adsorbed active agents was further analyzed using differential scanning calorimetry (DSC) and X-ray powder diffraction (XRPD). Dissolution studies revealed rapid release profiles within the first 3h. The viability of 3T3 endothelial cells was not affected in the presence of MSNs indicating negligible cytotoxicity. © 2009 Elsevier B.V.

Bouropoulos N.,University of Patras | Bouropoulos N.,Institute of Chemical Engineering And High Temperature Chemical Processes | Katsamenis O.L.,University of Patras | Katsamenis O.L.,University of Southampton | And 9 more authors.
Journal of Physical Chemistry C | Year: 2012

In this study, we aimed to use physicochemical and theoretical tools to understand fundamental problems of the interaction between lipid bilayers (Egg-PC liposomes) and unmodified C 60 fullerenes. The morphology, the size, and the electrokinetic properties of plain and C 60-loaded liposomes were investigated by means of atomic force microscopy, dynamic light scattering, and ζ-potential studies, respectively. The incorporation of C 60 molecules into the liposomes increases their size; however, there was no effect on their electrokinetic properties. Visualization studies revealed that the presence of C 60 in the membranes induced distortion in vesicle morphology, resulting in nonspherical vesicles. To elucidate further the impact of C 60 molecules on lipid bilayers, we assessed their miscibility by fluorescence spectroscopy measurements. Fluorescence measurements showed that the presence of C 60 in liposomes causes a pronounced effect on the Nile red emission spectrum due to alterations to the packing of the lipid membrane. The release of vesicle-encapsulated calcein was used as a measure of the integrity of the liposomes. Plain liposomes were found to be more stable compared with C 60-loaded (PC) liposomes, suggesting that C 60 ruptures the liposome membrane. Toxicity studies of C 60 in liposomes were carried out on cultured cells [rodent fibroblasts (3T3)] to assess further their toxicity. The results suggest that fullerene cytotoxic effect was reduced significantly after its incorporation into the liposomal bilayer after 24 h of incubation with the rodent fibroblasts (3T3). Finally, energy minimization studies were employed to underpin the experimental observations. The theoretical calculations show that low concentration of fullerene molecules present in the membrane had no effect on the membrane integrity; however, at high concentrations of fullerenes significant enlargement of the surface area is observed, supporting the experimental findings. © 2012 American Chemical Society.

Bakandritsos A.,University of Patras | Zboril R.,Palacky University | Bouropoulos N.,University of Patras | Bouropoulos N.,Institute of Chemical Engineering And High Temperature Chemical Processes | And 5 more authors.
Nanotechnology | Year: 2010

This paper reports an easy and highly reproducible preparation route, using self-emulsifying technology, for an orally administered high quality magnetically responsive drug delivery system. Hydrophobic iron oxide nanoparticles of about 5nm in diameter were prepared and incorporated into the lipid core of the produced oil droplets of a self-nanoemulsifying drug delivery system (MagC18/SNEDDS). The produced nanoemulsion exhibits colloidal stability at high ionic strengths and temperatures. The observed value of the saturation magnetization at 2K is ≈4.1emug-1. The nanoemulsion displayed the magnetic properties of a non-interacting assembly of superparamagnetic particles and a low blocking temperature. Moreover the effect of MagC18/SNEDDS on biological systems in vitro was investigated in rodent fibroblasts (3T3 cells). The cytotoxicity studies show that none of the formulations tested affected cell activity significantly over the 24h incubation. Such systems might have a potential use for oral delivery of poorly soluble compounds by extending the residence time of the formulation in the small intestine resulting in increased drug absorption values. © IOP Publishing Ltd.

Fatouros D.G.,University of Portsmouth | Douroumis D.,Universities of Kent Greenwich | Nikolakis V.,Institute of Chemical Engineering And High Temperature Chemical Processes | Ntais S.,Institute of Chemical Engineering And High Temperature Chemical Processes | And 6 more authors.
Journal of Materials Chemistry | Year: 2011

A combination of experiment and theory has been used to assess the potential use of the zeolite BEA as a drug delivery agent. Molecular dynamics (MD) has been used to examine the diffusion of two different drug molecules, salbutamol and theophylline, inside the zeolite BEA. MD shows that the two molecules display different diffusion behaviour, with the salbutamol molecule able to diffuse more freely than theophylline within the internal channel system of the zeolite. Several experimental techniques have been used to investigate the loading and release of the drug molecules from the BEA host. The results obtained support the observations from the modelling and suggest that modelling has an important role to play in screening zeolite-drug combinations prior to experimental investigation. © 2011 The Royal Society of Chemistry.

Wahab A.,Universities of Kent Greenwich | Wahab A.,Gomal University | Favretto M.E.,Universities of Kent Greenwich | Onyeagor N.D.,Universities of Kent Greenwich | And 5 more authors.
Journal of Microencapsulation | Year: 2012

The aim of this study was to assess acylated and non-acylated poly(glycerol adipate) polymers (PGA) as suitable nanoparticulate systems for encapsulation and release of ibuprofen, ibuprofen sodium salt (IBU-Na) and ketoprofen as model drugs. Drug encapsulated nanoparticles were prepared using the interfacial deposition method in the absence of surfactants. Physicochemical characterisation studies of the produced loaded nanoparticles showed that drugpolymer interactions depend on the characteristics of the actual active substance. IBU-Na showed strong interactions with the polymers and it was found to be molecularly dispersed within the polymer matrix while ibuprofen and ketoprofen retained their crystalline state. The drug release profiles showed stepwise patterns which involve an initial burst release effect, diffusion of the drug from the polymer matrix and eventually drug release possibly via a combined mechanism. PGA polymers can be effectively used as drug delivery carriers for various active substances. © 2012 Informa UK Ltd All rights reserved.

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