References of "Evrard, Brigitte"
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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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See detailIn vitro Biocompatibility and Genotoxicity Assessment of a Gentamicin-Loaded Monoolein Gel Intended to Treat of Chronic Osteomyelitis
Ouédraogo, M; Nacoulma, E.C; Semdé, R et al

in Journal of Pharmacology & Toxicology (2008), 3(5),

The aim of the study was to assess in vitro the biocompatibility and the genotoxicity of a gentamicin-loaded monoolein gel intended to treat of chronic osteomyelitis. Indeed, we are developing ... [more ▼]

The aim of the study was to assess in vitro the biocompatibility and the genotoxicity of a gentamicin-loaded monoolein gel intended to treat of chronic osteomyelitis. Indeed, we are developing biodegradable implants based on monoolein and gentamicin. The results of formulations, physico-chemical characterization of the formulated implants and in vitro release kinetic of gentamicin from implants were encouraging. As biocompatibility and absence of genotoxicity are the prerequisites for safe use of implants, we performed in vitro hemolysis, cytotoxicity and, genotoxicity tests. Hemolysis was evaluated by incubating human erythrocytes in direct contact with the implant whereas cytotoxicity was evaluated by 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) assay using fibroblasts and macrophages. Alkaline comet Assay was used to evaluate genotoxic potential of the implants. From these in vitro assays, the implant based on monoolein and gentamicin showed no genotoxic potential and has satisfactory biocompatibility. [less ▲]

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See detailIn vivo Biocompatibility and Toxicity Assessment of a Gentamicin-Loaded Monoolein Gel Intended to Treat Chronic Osteomyelitis
Ouédraogo, M; Sanou, M; Ramdé, N et al

in Journal of Pharmacology & Toxicology (2008), 3(5), 386-393

Biocompatibility and preliminary toxicity of a novel gentamicin-loaded monoolein gel (implant) intended for the local treatment of chronic osteomyelitis were investigated in mice. The mice, randomly ... [more ▼]

Biocompatibility and preliminary toxicity of a novel gentamicin-loaded monoolein gel (implant) intended for the local treatment of chronic osteomyelitis were investigated in mice. The mice, randomly allotted in 3 groups of 10, received respectively a single dose (0.05 mL) of normal saline, monoolein and the gel by subplantar injection. Clinical monitoring and assessment of induced oedema were carried out during 52 days after implantation. A histologic examination of the implantation site was performed at the end of the experiment. Renal and hepatic functions of the implant were also assessed on 52 days post-implantation by using biochemical and histological methods. In mice, no adverse reaction occurred after implantation. Only, a transitional foreign body reaction was observed in mice implanted by the monoolein and the implant. The paw volume of the mice increased within 3 h post-implantation and returned to baseline by 52 days. The liver and kidneys histology at light microscopy and biochemical parameters were similar for all mice. Further investigation is undertaken to detect eventual early damages which could have been resolved with time. Nevertheless, the novel gel is biocompatible and doesn`t show sub-chronic toxicity. [less ▲]

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See detailSynthesis and pharmacological evaluation of a new targeted drug carrier system: β-Cyclodextrin coupled to oxytocin
Bertolla, C; Rolin, S; Evrard, Brigitte ULg et al

in Bioorganic & Medicinal Chemistry Letters (2008), 18

β-Cyclodextrin (β-CD) was monofunctionalized into its carboxylic derivative and then conjugated to the N-side of oxytocin (OT), a nonapeptide involved in human behavior and myometrium contraction. On ... [more ▼]

β-Cyclodextrin (β-CD) was monofunctionalized into its carboxylic derivative and then conjugated to the N-side of oxytocin (OT), a nonapeptide involved in human behavior and myometrium contraction. On isolated rat myometrium, this conjugate (β-CD-OT) partly preserves the contracting activity of OT (EC50 = 0.40 μM vs 1.7 nM). Moreover, the contraction induced frequency is also lowered by β-CD-OT. This novel hydrophilic targeted carrier could form a host–guest complex with prostaglandins and their derivatives used as labor inducers or with anticancer drugs used in cervix and endometrial cancer. This strategy can improve the solubility, the stability, and/or the biological activity of these drugs as well as reducing their side-effects. [less ▲]

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See detailMonoolein-water liquid crystalline gels of gentamicin as bioresorbable implants for the local treatment of chronic osteomyelitis: in vitro characterization
Ouédraogo, M; Semdé, R; Somé, I.T et al

in Drug Development & Industrial Pharmacy (2008), 34

To maximize the efficacy of chronic osteomyelitis antibiotherapy while reducing antibiotic systemic toxicity, as well as time and costs of hospitalizations, it has been thought that monoolein-water gels ... [more ▼]

To maximize the efficacy of chronic osteomyelitis antibiotherapy while reducing antibiotic systemic toxicity, as well as time and costs of hospitalizations, it has been thought that monoolein-water gels incorporating gentamicin sulfate could be used as local, bioresorbable,and sustained-release implants. For this purpose, four formulations were examined with regard to their physicochemical and in vitro drug release characteristics. Hot stage microscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA),and X-ray diffraction showed cubic liquid crystalline and eutectic structures. The more suitable formulation consisting of 80-15-5%wt/wt monoolein-water-gentamicin sulfate progressively released the antibiotic for a period of 3 weeks without burst effect. Moreover, the content and the release profile of gentamicin sulfate were not significantly changed after storage at 2-6 degrees C for a period of 10 months. [less ▲]

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