References of "Evrard, Brigitte"
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See detailOptimisation and validation of a fast HPLC method for the quantitation of sulindac and its impurities
Krier, Fabrice ULg; Brion, Michaël; Debrus, Benjamin ULg et al

Poster (2010, September)

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See detailThe experimental design as practical approach to develop and optimize a formulation of peptide-loaded liposomes
Ducat, Emilie ULg; Brion, Michael; Lecomte, Frédéric ULg et al

in AAPS PharmSciTech (2010), 11(2), 966-975

To investigate the encapsulation of Print 3G, a peptidic agent that could reduce the angiogenic development of breast tumors, pegylated liposomes used as intravenous vectors were studied and characterized ... [more ▼]

To investigate the encapsulation of Print 3G, a peptidic agent that could reduce the angiogenic development of breast tumors, pegylated liposomes used as intravenous vectors were studied and characterized. Recently, the path of liposomes has been explored with success to improve the pharmacological properties of peptidic drugs and to stabilize them. In this study, loaded unilamellar vesicles composed of SPC:CHOL:mPEG2000-DSPE (47:47:6) were prepared by the hydration of lipid film technique. An HPLC method was developed and validated for the determination of Print 3G to calculate its encapsulation efficiency. Observed Print 3G adsorption on different materials employed during liposome preparation (such as glass beads, tubing, and connections for extrusion) led to the modification of the manufacturing method. The freeze-thawing technique was used to enhance the amount of Print 3G encapsulated into blank liposomes prepared using the hydration of lipid film procedure. Many factors may influence peptide entrapment, namely the number of freeze-thawing cycles, the lipid concentration, the peptide concentration, and the mixing time. Consequently, a design of experiments was performed to obtain the best encapsulation efficiency while minimizing the number of experiments. The lipid concentration and the number of freeze-thawing cycles were identified as the positive factors influencing the encapsulation. As a result of the optimization, an optimum was found and encapsulation efficiencies were improved from around 30% to 63%. Liposome integrity was evaluated by photon correlation spectroscopy and freeze-fracture electron microscopy to ensure that the selected formulation possesses the required properties to be a potential candidate for further in vitro and in vivo experiments. [less ▲]

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See detailTechnologie Pharmaceutique et Biopharmacie
Evrard, Brigitte ULg

Learning material (2010)

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See detailComparison of chitosan/siRNA and trimethylchitosan/siRNA complexes behaviour in vitro
Dehousse, Vincent ULg; Garbacki, Nancy ULg; Jaspart, Séverine ULg et al

in International Journal of Biological Macromolecules (2010), 46

Chitosan and trimethylchitosan (TMC)-siRNA nanoparticles were produced by simple complexation technique or by ionic gelation using tripolyphosphate (TPP). The obtained complexes were characterized in ... [more ▼]

Chitosan and trimethylchitosan (TMC)-siRNA nanoparticles were produced by simple complexation technique or by ionic gelation using tripolyphosphate (TPP). The obtained complexes were characterized in terms of physicochemical properties such as size, zeta potential, complexation efficiency and stability. Furthermore, cytotoxicity, cell uptake and transfection efficiency of polyplexes were evaluated in vitro. Under pH condition of cell culture medium, a strong decrease in siRNA condensation efficiency was observed with chitosan nanoparticles. This characteristic resulted in low transfection efficiencies in HEK293 cell line. Formulation of chitosan polyplexes with TPP led to improvement of polyplexes stability but no significant increase in transfection efficiency was observed compared to simple chitosan complexes. By contrast, TMC complexes did not have pH dependency on siRNA complexation. TMCsiRNA nanoparticles were stable in physiological condition. Accordingly, cellular uptake was increased compared to chitosan polyplexes. However, improvement of transfection efficiency was low regarding to cellular uptake of these complexes. Chitosan and TMC complexes present some characteristics favourable for siRNA delivery, such as ability to integrate siRNA into small discrete particles or low toxicity of the complexes. This study also highlights the importance of complexes stability in physiological environment for siRNA transfection purposes. [less ▲]

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See detailDevelopment of pH–responsive nanocarriers using trimethylchitosans and methacrylic acid copolymer for siRNA delivery
Dehousse, Vincent ULg; Garbacki, Nancy ULg; Colige, Alain ULg et al

in Biomaterials (2010), 31

RNA interference-based therapies are dependent on intracellular delivery of siRNA. The release of siRNA from the endosomal compartment may be a rate limiting step in the transfection process. The purpose ... [more ▼]

RNA interference-based therapies are dependent on intracellular delivery of siRNA. The release of siRNA from the endosomal compartment may be a rate limiting step in the transfection process. The purpose of this study was to produce pH–responsive nanocarriers made of trimethylchitosan (TMC). To this end, pHsensitive methacrylic acid (MAA) copolymer was added to TMC–siRNA formulations. Four different TMCs associated or not with MAA were evaluated as siRNA carriers. Nanoparticles were characterized in terms of size, surface charge, morphology and interaction with siRNA. A swelling behaviour due to a decrease in pH was observed and was found to be dependent on MAA content in the complexes. In vitro experiments aimed at evaluating how the capacity of the nanocarriers to transfect siRNA in L929 cells was affected by MAA content. Confocal microscopy experiments showed that fluorescent MAA-containing particles exhibit a different distribution pattern inside the cells comparing to their counterpart without this pH-sensitive polymer. Transfection efficiency was investigated by RhoA mRNA expression inhibition. MAA–TMC–siRNA complexes were able to transfect L929 cells with greater efficiency than corresponding TMC–siRNA complexes. This study gives an insight into the opportunity of pH-sensitive nanocarriers for siRNA delivery. Such formulations may represent an attractive strategy to improve endosomal escape of siRNA. [less ▲]

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See detailAcetaminophen determination in low-dose pharmaceutical syrup by NIR spectroscopy
Ziemons, Eric ULg; Mantanus, Jérôme ULg; Lebrun, Pierre ULg et al

in Journal of Pharmaceutical & Biomedical Analysis (2010), 53

The aim of the present study was first to develop a robust near infrared (NIR) calibration model able to determine the acetaminophen content of a low-dose syrup formulation (2 % (w/v)). Therefore ... [more ▼]

The aim of the present study was first to develop a robust near infrared (NIR) calibration model able to determine the acetaminophen content of a low-dose syrup formulation (2 % (w/v)). Therefore, variability sources such as production campaigns, batches, API concentration, syrup basis, operators and sample temperatures were introduced in the calibration set. A prediction model was then built using Partial Least Square (PLS) regression. First derivative followed by Standard Normal Variate (SNV) were chosen as signal pre-processing. Based on the random subsets cross validation, 4 PLS factors were selected for the prediction model. The method was then validated for an API concentration ranging from 16 to 24 mg/mL (1.6-2.4 % (w/v)) using an external validation set. The 0.26 mg/mL RMSEP suggested the global accuracy of the model. The accuracy profile obtained from the validation results, based on tolerance intervals, confirmed the adequate accuracy of the results generated by the method all over the investigated API concentration range. Finally, the NIR model was used to monitor in real time the API concentration while mixing syrups containing various amounts of API, a good agreement was found between the NIR method and the theoretical concentrations. [less ▲]

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See detailEffect of β-cyclodextrin and its derivatives on caveolae disruption, relationships with their cholesterol extraction capacities
Castagne, Delphine ULg; Evrard, Brigitte ULg; Nusgens, Betty ULg et al

in Journal of Inclusion Phenomena and Macrocyclic Chemistry (2010), 67

Endothelial cells (HUVEC) were treated with b-cyclodextrin (b-CD) and hydroxypropylated or methylated derivatives solutions to confirm their lack of affinity with phospholipids and their specificity ... [more ▼]

Endothelial cells (HUVEC) were treated with b-cyclodextrin (b-CD) and hydroxypropylated or methylated derivatives solutions to confirm their lack of affinity with phospholipids and their specificity towards cholesterol. Further studies were performed on bovine aortic endothelial cells to assess the effect of b-CDs (mainly methylated derivatives) on membrane microdomains (lipid rafts or caveolae), by detecting the caveolae marker caveolin-1 in fractions of sucrose gradients. A displacement from the lighter to the heavier fractions, characteristic of caveolae disruption, was observed using CDs. The strongest effect was obtained with dimethyl-b-CD, for which an accumulation of caveolin-1 was observed in the bottom of the gradient. Crysmeb and trimethyl-b-CD seemed to have the weaker effects as a significative amount of caveolin-1 was still detected in the light fraction corresponding to caveolae. b-CD and CDs having a degree of methylation a bit lower than 2 showed intermediate effects. The results of the present study on microdomains seem in good correlation with the cell cholesterol extraction capacities of CDs previously determined. [less ▲]

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See detailSuggested mechanism of action of classical and deformable liposomes through pig ear skin
Gillet, Aline ULg; Lecomte, Frédéric ULg; Rozet, Eric ULg et al

in Journal of Pharmacy & Pharmacology (2010), 62(6), 788-807

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See detailActive content determination of non-coated pharmaceutical pellets by near infrared spectroscopy: Method development, validation and reliability evaluation
Mantanus, Jérôme ULg; Ziemons, Eric ULg; Lebrun, Pierre ULg et al

in Talanta (2010), 80

A robust near infrared (NIR) method able to quantify the active content of pilot non-coated pharmaceutical pellets was developed. A protocol of calibration was followed, involving 2 operators, independent ... [more ▼]

A robust near infrared (NIR) method able to quantify the active content of pilot non-coated pharmaceutical pellets was developed. A protocol of calibration was followed, involving 2 operators, independent pilot batches of non-coated pharmaceutical pellets and two different NIR acquisition temperatures. Prediction models based on Partial Least Squares (PLS) regression were then carried out. Afterwards, the NIR method was fully validated for an active content ranging from 80 to 120% of the usual active content using new independent pilot batches to evaluate the adequacy of the method to its final purpose. Conventional criteria such as the R2, the Root Mean Square Error of Calibration (RMSEC), the Root Mean Square Error of Prediction (RMSEP) and the number of PLS factors enabled the selection of models with good predictive potential. However, such criteria sometimes fail to choose the most fitted for purpose model. Therefore, a novel approach based on accuracy profiles of the validation results was used, providing a visual representation of the actual and future performances of the models. Following this approach, the prediction model using signal pre-treatment Multiplicative Scatter Correction (MSC) was chosen as it showed the best ability to quantify accurately the active content over the 80–120% active content range. The reliability of the NIR method was tested with new pilot batches of non-coated pharmaceutical pellets containing 90 and 110% of the usual active content, with blends of validation batches and industrial batches. All those batches were also analyzed by the HPLC reference method and relative errors were calculated: the results showed low relative errors in full accordance with the results obtained during the validation of the method, indicating the reliability of the NIR method and its interchangeability with the HPLC reference method. [less ▲]

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See detailSpectroscopic studies and molecular modeling for understanding the interactions between cholesterol and cyclodextrins
Castagne, Delphine ULg; Dive, Georges ULg; Evrard, Brigitte ULg et al

in Journal of Pharmacy & Pharmaceutical Sciences : A Publication of the Canadian Society for Pharmaceutical Sciences (2010), 13(2), 362-377

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See detailLocal applications of GM-CSF induce the recruitment of immune cells in cervical low-grade squamous intraepithelial lesions.
Hubert, Pascale ULg; Doyen, Jean ULg; Capelle, Xavier ULg et al

in American Journal of Reproductive Immunology (2010), 64(2), 126-136

Abstract Problem Quantitative alterations of antigen-presenting cells (APC) in (pre)neoplastic lesions of the uterine cervix associated with human papillomavirus (HPV) infection suggest a diminished ... [more ▼]

Abstract Problem Quantitative alterations of antigen-presenting cells (APC) in (pre)neoplastic lesions of the uterine cervix associated with human papillomavirus (HPV) infection suggest a diminished capacity to capture viral antigens and to induce a protective immune response. Method of study To test if a cervical application of GM-CSF could restore an immune response against HPV in women with cervical low-grade squamous intraepithelial lesions (LSIL). We performed two clinical trials with11 healthy women and 15 patients with LSIL. Results GM-CSF applications were well tolerated in all enrolled women and no difference in toxicity between the treated and placebo groups was observed during the follow up (until 30 months). Interestingly, in the GM-CSF treated group, a significant increased APC and cytotoxic T lymphocyte infiltration was observed in the cervical biopsies with no change in regulatory T cell numbers. All the HPV16+ patients exhibited an immune response against HPV16 after GM-CSF applications, as shown by NK and/or T cells producing IFN-γ whereas no cellular immune response was observed before the treatment. Moreover, the anti-VLP antibody titers also increased after the treatment. Conclusion These encouraging results obtained from a limited number of subjects justify further study on the therapeutic effect of APC in cervical (pre)neoplastic lesions. [less ▲]

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