References of "Evrard, Brigitte"
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See detailCARACTERISATION ET OPTIMISATION DE L’ENCAPSULATION D’UN PEPTIDE ANTAGONISTE D’ONCOPROTEINE AU SEIN DE LIPOSOMES PEGYLES
Ducat, Emilie ULg; Brion, Michael; Evrard, Brigitte ULg et al

Scientific conference (2009)

Introduction : Print 3G est un peptide antagoniste d’une oncoprotéine impliquée dans le cancer du sein, composé de 25 acides aminés. Le but de ce travail est d’étudier l’encapsulation de ce peptide au ... [more ▼]

Introduction : Print 3G est un peptide antagoniste d’une oncoprotéine impliquée dans le cancer du sein, composé de 25 acides aminés. Le but de ce travail est d’étudier l’encapsulation de ce peptide au sein de liposomes pegylés. Deux types de formulations de liposomes ont été étudiés, le premier contenant des mPEG750-DSPE et le second des mPEG2000-DSPE. Méthode : Des liposomes unilamellaires composés de SPC:CHOL:mPEG750-DSPE ou de SPC:CHOL:mPEG2000-DSPE (47:47:6) encapsulant le peptide ont été préparés par la technique d’évaporation du film. L’observation d’une adsorption conséquente de Print 3G sur les instruments utilisés a conduit à l’utilisation de la méthode de fabrication par cycles gel-dégel. Etant donné que plusieurs facteurs peuvent influencer l’encapsulation du peptide à l’intérieur des liposomes, une planification expérimentale a été engagée (pour le screening, un plan de Plackett et Burman et pour l’optimisation, un plan composite faces centrées). Résultats : Par la technique des cycles gel-dégel généralement décrite dans la littérature(1; 2), les taux d’encapsulation obtenus étaient de 17,26 ± 0,46 % (n=3) pour les liposomes contenant des mPEG750 et de 26,20 ± 7,98 % (n=3) pour ceux contenant des mPEG2000. Le plan de screening a permis de dégager deux facteurs ayant une influence positive sur l’encapsulation : la concentration en lipides et le nombre de cycles gel-dégel. Ceux-ci ont été optimisés pour chaque type de mPEG. Les résultats obtenus pour les mPEG2000 mettent en évidence un optimum théorique de 64,75% pour un nombre de cycles égal à 11 et pour une concentration en lipides SPC:CHOL:mPEG2000-DSPE de 36.1mM:36.1mM:4mM. Les résultats expérimentaux ont permis d’obtenir un taux d’encapsulation de 62,68 ± 2,93 %. Conclusion et perspectives : Le changement de technique de fabrication a permis l’encapsulation significative du peptide à l’intérieur des liposomes. La planification expérimentale a ensuite conduit à l’amélioration significative des taux d’encapsulation pour les liposomes contenant des mPEG2000. Par la suite, un plan d’optimisation pour les liposomes contenant des mPEG750 sera mis en œuvre. Remerciements: Ces recherches ont été réalisées avec le soutien de la Région Wallonne. Références: 1. Y.Katanasaka, T.Ida, T.Asai, N.Maeda, and N.Oku. Effective delivery of an angiogenesis inhibitor by neovessel-targeted liposomes. International Journal of Pharmaceutics, 360 (1-2):219-224 (2008). 2. G.A.Ramaldes, J.-R.Deverre, J.-M.Grognet, F.Puisieux, and E.Fattal. Use of an enzyme immunoassay for the evaluation of entrapment efficiency and in vitro stability in intestinal fluids of liposomal bovine serum albumin. International Journal of Pharmaceutics, 143 (1):1-11 (1996). [less ▲]

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See detailPorous pellets as drug delivery system
Cosijns, A; Nizet, D; Nikolakakis, I et al

in Drug Development & Industrial Pharmacy (2009), 35(6), 655-662

Background: Multi particulate drug delivery systems, such as pellets, are frequently used as they offer therapeutic advantages over single-unit dosage forms. Aim: Development of porous pellets followed by ... [more ▼]

Background: Multi particulate drug delivery systems, such as pellets, are frequently used as they offer therapeutic advantages over single-unit dosage forms. Aim: Development of porous pellets followed by evaluation of potential drug loading techniques. Method: Porous microcrystalline pellets were manufactured and evaluated as drug delivery system. Pellets consisting of Avicel PH 101 and NaCl (70%,w/w) were prepared by extrusion/spheronization. The NaCl fraction was extracted with water and after drying porous pellets were obtained (33.2% porosity). Immersion of the porous pellets in a 15% and 30% (w/v) metoprolol tartrate solution, ibuprofen impregnation via supercritical fluids and paracetamol layering via fluidized bed coating were evaluated as drug loading techniques. Results: Raman spectroscopy revealed that immersion of the pellets in a drug solution and supercritical fluid impregnation allowed the drug to penetrate into the porous structure of the pellets. The amount of drug incorporated depended on the solubility of the drug in the solvent (water or supercritical CO2). Drug release from the porous pellets was immediate and primarily controlled by pure diffusion. Conclusion: The technique described in this research work is suitable for the production of porous pellets. Drug loading via immersion the pellets in a drug solution and supercritical fluid impregnation resulted in a drug deposition in the entire pellet in contrast to fluid bed layering where drugs were only deposed on the pellet surface. [less ▲]

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See detailSparing methylation of β-cyclodextrin mitigates cytotoxicity and permeability induction in respiratory epithelial cell layers in vitro
Belhadj Salem, L.; Bosquillon, C.; Dailey, L. A. et al

in Journal of Controlled Release (2009), 136

Cyclodextrins (CDs) are promising solubility enhancers for inhaled drug delivery. However, they have dose-dependent effects on the respiratory epithelium, which may have advantages for permeability ... [more ▼]

Cyclodextrins (CDs) are promising solubility enhancers for inhaled drug delivery. However, they have dose-dependent effects on the respiratory epithelium, which may have advantages for permeability enhancement but also gives rise to safety concerns. In this study, the methyl thiazol tetrazolium (MTT) assay was used to compare a new sparingly methylated β-CD, Kleptose® Crysmeβ (Crysmeb) with the more established CD derivatives hydroxypropyl-γ-cyclodextrin (HPγCD), randomly methylated β-cyclodextrin (Rameb) and hydroxypropyl-β-cyclodextrin (HPβCD). The βCD derivatives affected cell metabolism in A549 cells in a concentration dependent manner with LDso of 56, 31 and 11 mM obtained for HPβCD, Crysmeb and Rameb, respectively. Calu-3 cells were less susceptible to βCD with an LDso of 25 mM being obtained for Rameb only. Permeability increases in Calu-3 cell layers were observed with βCD derivatives and a concentration dependency shown. The mechanism of permeability enhancement and its reversibility was investigated. Rameb produced an irreversible loss of cell layer barrier function at ≥25 mM, but perturbations of epithelial integrity were moderate and reversible in the case of HPβCD and Crysmeb (25-50 mM). Given its high solubilisation capacity, the low toxicity and transient absorption promoting properties, this study identifies Crysmeb as a promising adjuvant in formulations for inhalation. [less ▲]

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See detailPreliminary studies of development of oral pharmaceutical dosage forms contained extracts of Artemisia annua cultivated in Benin
Zime Diawara, Hermine; Gbaguidi, Fernand; Gbenou, Joachim et al

in Proceedings of 2nd PharmSci Fair (2009)

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See detailControlled release of drugs from multi-component biomaterials
Zalfen, Alina ULg; Nizet, D.; Jérôme, Christine ULg et al

in Acta Biomaterialia (2008), 4(6), 1788-1796

In order to control their release, drugs are encapsulated into systems which are expected to provide a certain site with a predetermined amount of drug over a well-defined period of time. Here we report ... [more ▼]

In order to control their release, drugs are encapsulated into systems which are expected to provide a certain site with a predetermined amount of drug over a well-defined period of time. Here we report on a multi-component drug delivery biomaterial that consists of a hydrogel matrix in which drug-loaded biodegradable microcarriers are dispersed, and whose potential applications could be found in the design of implantable devices with long-term activity, as required by contraceptive and hormone replacement treatments. The release profile of the drug can actually be tuned by the complex interplay of several release mechanisms, including the permeability and eventually the degradation rate of the microcarriers and the diffusion through the hydrogel. The hydrogel consisted of 2-hydroxyethyl methacrylate cross-linked by ethylene glycol dimethacrylate. The microcarriers were biodegradable poly-ε-caprolactone (PCL) microspheres in which active molecules, such as levonorgestrel (LNG), were encapsulated. The hydrogels were characterized by water swelling, thermal properties, LNG diffusion through drug-free and drug-depleted hydrogel membranes and LNG release from devices with drug dispersed in the hydrogel. The PCL microspheres were observed by scanning electron microscopy; their size distribution, LNG loading and release were also investigated. The hydrogel-microsphere assemblies were characterized in terms of the distribution of the microspheres within the hydrogel, water swelling and the release of the encapsulated molecules. The developed device, due to its composite structure, has the ability to combine several release mechanisms, leading to drug release obeying zero-order kinetics for most of the time. [less ▲]

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See detailActive Substance Delivery System Comprising A Hydrogel Matrix And Microcarriers
Maquet, Véronique; Pagnoulle, Christophe; Evrard, Brigitte ULg et al

Patent (2008)

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See detailTheoretical and Experimental Vibrational Study of Miconazole and Its Dimers with Organic Acids: Application to the IR Characterization of Its Inclusion Complexes with Cyclodextrins
Barillaro, Valéry; Dive, Georges ULg; Ziemons, Eric ULg et al

in International Journal of Pharmaceutics (2008), 350(1-2), 155-165

The geometry, frequency and intensity of the vibrational bands of miconazole were derived from the density functional theory (DFT) calculations with the hybrid functional B3LYP and the 6-31G(d) basis set ... [more ▼]

The geometry, frequency and intensity of the vibrational bands of miconazole were derived from the density functional theory (DFT) calculations with the hybrid functional B3LYP and the 6-31G(d) basis set. Starting from the fully AM1 optimized geometries of miconazole/betaCD/acids complexes, the miconazole/acid dimers were reoptimized at the B3LYP/6-31G(d) level. Three acids were studied: maleic, fumaric and l-tartaric acids. To begin with the vibrational spectral data obtained from solid phase in mid FT-IR spectrum of miconazole and its dimers are assigned based on the results of the normal modes calculations. All the observed spectra and the calculated ones are found to be in good agreement. In a second step, theoretical results allowed the assignment of FT-IR spectrum for the miconazole/HPgammaCD inclusion complex produced by supercritical carbon dioxide treatment and confirmed the inclusion of miconazole. The experimental spectra for the miconazole/HPgammaCD/acids complexes prepared by supercritical carbon dioxide processing were also assigned using theoretical results. The results confirmed the presence of a genuine inclusion complex and also the interaction between miconazole and the acid. [less ▲]

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See detailTheoretical and Experimental Investigations of Organic Acids/Cyclodextrin Complexes and Their Consequences Upon the Formation of Miconazole/Cyclodextrin/Acid Ternary Inclusion Complexes
Barillaro, Valéry; Dive, Georges ULg; Bertholet, Pascal et al

in International Journal of Pharmaceutics (2008), 347(1-2), 62-70

(1)H NMR spectrometry, FT-IR spectroscopy, as well as molecular modeling at the AM1 level and normal mode analysis were used to characterise the interactions and the formation of inclusion complexes ... [more ▼]

(1)H NMR spectrometry, FT-IR spectroscopy, as well as molecular modeling at the AM1 level and normal mode analysis were used to characterise the interactions and the formation of inclusion complexes between three organic acids: maleic, fumaric, L-tartaric acids and betaCD. In aqueous medium, the complexation was confirmed by (1)H NMR spectroscopy using two-dimensional technique. The stable geometries of the complexes were determined by molecular modeling. Experimental infrared frequencies were assigned on the base of the vibrational normal mode calculation at the fully optimized geometry for the inclusion complexes. All the results point out the presence of stable inclusion complexes between acids and betaCD at the solid state. These results show the double role of the acid. Correlated with the theoretical and experimental data previously obtained for the miconazole/CD/acids complexes, in function of both acids and CDs structures, the acids can either stabilize the complexes by formation of a multicomponent complex or form acid/CD inclusion complexes, hindering the guest inclusion. [less ▲]

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See detailUse of supercritical fluids technology (PGSS) for the production of betametazone loaded solid lipid microparticles
Nizet, Dominique; Jaspart, Séverine ULg; Brion, Michael et al

Poster (2008)

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See detailSTUDY OF PEGYLATED LIPOSOMES CRYOPROTECTION IN TERMS OF RETENTION EFFICIENCY
Ducat, Emilie ULg; Evrard, Brigitte ULg; Piel, Géraldine ULg

Poster (2008)

Purpose: Print 3G, a peptidic antagonist of oncoproteins involved in breast cancer, was encapsulated in PEGylated liposomes. Seeing its temperature instability, this peptide must be stored at – 20°C. In ... [more ▼]

Purpose: Print 3G, a peptidic antagonist of oncoproteins involved in breast cancer, was encapsulated in PEGylated liposomes. Seeing its temperature instability, this peptide must be stored at – 20°C. In this study, the cryoprotection of PEGylated liposomes was investigated to ensure their stability in terms of size and retention capacity when frozen. Calcein, a self-quenching fluorescent marker encapsulated in liposomes, was used as a tracer of liposome integrity. The release of calcein was studied before and after freezing, with or without cryoprotectants at several concentrations. Methods: Unilamellar vesicles made of SPC:CHOL:mPEG-750-DSPE (47:47:6) or SPC:CHOL:mPEG-2000-DSPE (47:47:6) were prepared by the film evaporation method. Size of the liposomes dispersions containing a cryoprotectant (sucrose, trehalose or lysine) at various concentrations were measured by photon correlation spectroscopy before and after freezing. From these results, two cryoprotectants (at the best molar ratio of sugar-to-lipid) were chosen for future experiments with calcein. Its release from the inner cavity of liposomes was measured fluorometrically before and after freezing, with or without cryoprotectant. The percentage of calcein retained was determined at excitation and emission wavelengths of 490 and 520 nm, respectively. The liposomes were prepared with cryoprotectant either only outside the vesicles or both inside and outside. Results: In regards to the results obtained with PCS, sucrose and trehalose (molar ratio of sugar-to-lipid = 4) were selected for calcein experiments. The best results in terms of retention efficiency were obtained using cryoprotectant inside and outside the vesicles. Liposomes containing mPEG-750-DSPE show the best retention efficiency after freezing with trehalose (75.42 ± 2.39 %, n=3) in comparison with sucrose (62.16 ± 4.34 %, n=3). Liposomes containing mPEG-2000-DSPE doesn’t show significant difference (T-Test) between trehalose (84.27 ± 5.05%, n=3) and sucrose (83.38 ± 3.18 %, n=3). In the future experiments, these results will be compared with experiments of frozen liposomes encapsulating Print 3G. Acknowledgements: This work was supported by the Ministry of the Walloon Region. [less ▲]

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See detailDEVELOPMENT OF AN INTRAPERITONEAL IMPLANT FOR THE ENDOMETRIOSIS TREATMENT
Krier, Fabrice ULg; Nizet, Dominique; Riva, Raphaël ULg et al

Poster (2008)

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See detailPreliminary Clinical Assessment of a Gentamicin-Loaded Monoolein Gel Intended to Treat Chronic Osteomyelitis
Ouédraogo, M; Da, C.S; Nacoulma, I.S et al

in Trends in Medical Research (2008), 3(2), 82-89

The aim of this current study was to perform a preliminary clinical assessment of efficacy and safety of a biodegradable gentamicin-loaded monoolein gel. An open single dose, one treatment study including ... [more ▼]

The aim of this current study was to perform a preliminary clinical assessment of efficacy and safety of a biodegradable gentamicin-loaded monoolein gel. An open single dose, one treatment study including 19 patients with chronic osteomyelitis caused by a microorganism sensitive to gentamicin was conducted. After surgical curettage of the infected bone, the dead space was filled in with the gentamicin-loaded monoolein gel. To prevent post-operative septicaemia, a systemic antibiotherapy was prescribed for 3 days following the operation. Clinical, biological and radiological follow-up was performed to assess the efficacy and the safety of the treatment. After a follow-up period ranging from 2 to 12 months, all 19 patients included in the study felt well. Eighteen patients recovered from chronic osteomyelitis without adverse events. The wound of one patient whose bone was exposed did not scar over after 10 months. However, it was no longer infected. In conclusion, gentamicin-loaded monoolein gel was efficacious in treating chronic osteomyelitis without side-effects. [less ▲]

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