References of "Evrard, Brigitte"
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See detailLiposomes and parameters affecting their skin penetration behaviour
Gillet, Aline ULg; Evrard, Brigitte ULg; Piel, Géraldine ULg

in Journal of Drug Delivery Science and Technology [=JDDST] (2011), 21

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See detailNuclear delivery of a therapeutic peptide by long circulating pH-sensitive liposomes: Benefits over classical vesicles.
Ducat, Emilie ULg; Deprez, Julie ULg; Gillet, Aline ULg et al

in International Journal of Pharmaceutics (2011)

The purpose of this study is to propose a suitable vector combining increased circulation lifetime and intracellular delivery capacities for a therapeutic peptide. Long circulating classical liposomes ... [more ▼]

The purpose of this study is to propose a suitable vector combining increased circulation lifetime and intracellular delivery capacities for a therapeutic peptide. Long circulating classical liposomes [SPC:CHOL:PEG-750-DSPE (47:47:6 molar% ratio)] or pH-sensitive stealth liposomes [DOPE:CHEMS:CHOL:PEG(750)-DSPE (43:21:30:6 molar% ratio)] were used to deliver a therapeutic peptide to its nuclear site of action. The benefit of using stealth pH-sensitive liposomes was investigated and formulations were compared to classical liposomes in terms of size, shape, charge, encapsulation efficiency, stability and, most importantly, in terms of cellular uptake. Confocal microscopy and flow cytometry were used to evaluate the intracellular fate of liposomes themselves and of their hydrophilic encapsulated material. Cellular uptake of peptide-loaded liposomes was also investigated in three cell lines: Hs578t human epithelial cells from breast carcinoma, MDA-MB-231 human breast carcinoma cells and WI-26 human diploid lung fibroblast cells. The difference between formulations in terms of peptide delivery from the endosome to the cytoplasm and even to the nucleus was investigated as a function of time. Characterization studies showed that both formulations possess acceptable size, shape and encapsulation efficiency but cellular uptake studies showed the important benefit of the pH-sensitive formulation over the classical one, in spite of liposome PEGylation. Indeed, stealth pH-sensitive liposomes were able to deliver hydrophilic materials strongly to the cytoplasm. Most importantly, when encapsulated in pH-sensitive stealth liposomes, the peptide was able to reach the nucleus of tumorigenic and non tumorigenic breast cancer cells. [less ▲]

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See detailValidation, transfer and measurement uncertainty estimation of an HPLC-UV method for the quantification of artemisinin in hydro alcoholic extracts of Artemisia annua L.
ZIME DIAWARA, H.; GBAGUIDI, F.; Evrard, Brigitte ULg et al

in Journal of Pharmaceutical & Biomedical Analysis (2011), 56

Malaria is the world’s most important parasitic infection with 500 millions cases annually and almost 2 millions death per year. This disease is more present in Sub-Saharan Africa where 90% of the ... [more ▼]

Malaria is the world’s most important parasitic infection with 500 millions cases annually and almost 2 millions death per year. This disease is more present in Sub-Saharan Africa where 90% of the infections are found. Artemisinin and its semi synthetic derivatives (artemether, artesunate) have actually the most powerful activity on malaria, even in its complicated forms and resistance cases. Various methods have been proposed for detection and quantification of artemisinin in Artemisia annua L. by HPLC-UV, but the plant extracts used for this quantification were extracts obtained with organic solvents (toluene, petroleum ether, hexane …). To be able to use crude A. annua extracts prepared at low cost to formulate antipaludic drugs, we chose the use of a mixture of water and ethanol as solvent of extraction, but no adequate analytical method for this kind of extracts is published. The main objectives of this work were first to develop an analytical method for artemisinin quantification in hydro alcoholic extracts of A. annua. Second, this method had to be thoroughly validated by the research and development laboratory and, third, the transfer of this method to the routine laboratory had to be demonstrated. The final aim was to compare the estimation of measurement uncertainty obtained during the method validation with validation standards to measurement uncertainty estimates obtained during the method transfer study with real samples. The method was validated following the accuracy profile methodology and was found to be accurate in the concentration range of 10.0 to 54.0 µg/ml with CV <8%. Limit of detection and of quantification were 2.73 and 10.0 µg/ml, respectively. The method was then successfully transferred to a laboratory in Benin by showing that the quality of the results that it will generate during routine application of the method is sufficient. Finally, the measurement uncertainty of the method was estimated from the validation experiments as well as from the transfer study with authentic unspiked samples of A. annua. The comparison of these measurement uncertainty estimations showed that they were coherent. It confirmed thus that the estimation of measurement uncertainty from validation experiments predicts well the measurement uncertainty of real routine samples. This analytical method was thus shown to be convenient for routine analysis of hydro alcoholic extracts of A. annua in Benin. [less ▲]

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See detailIn vivo biocompatibility of three potential intraperitoneal implants
Defrère, Sylvie; Mestdagt, Mélanie ULg; Riva, Raphaël ULg et al

in Macromolecular Bioscience (2011), 11(10), 1335-45

The intraperitoneal biocompatibility of PDMS, polyHEMA and pEVA was investigated in rats, rabbits and rhesus monkeys. No inflammation was evidenced by hematological analyses and measurement of ... [more ▼]

The intraperitoneal biocompatibility of PDMS, polyHEMA and pEVA was investigated in rats, rabbits and rhesus monkeys. No inflammation was evidenced by hematological analyses and measurement of inflammatory markers throughout the experiment and by post-mortem examination of the pelvic cavity. After 3 or 6 months, histological analysis revealed fibrous tissue encapsulating PDMS and PEVA implants in all species and polyHEMA implants in rabbits and monkeys. Calcium deposits were observed inside polyHEMA implants. The intraperitoneal biocompatibility of all 3 polymers makes them suitable for the design of drug delivery systems, which may be of great interest for pathologies confined to the pelvic cavity. [less ▲]

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See detailCellular uptake of liposomes monitored by confocal microscopy and flow cytometry
Ducat, Emilie ULg; Evrard, Brigitte ULg; Peulen, Olivier ULg et al

in Journal of Drug Delivery Science and Technology [=JDDST] (2011), 21(6), 469-477

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See detailPowdered lipid nano and microparticles : production and applications
Berton, Amandine; Piel, Géraldine ULg; Evrard, Brigitte ULg

in Recent Patents on Drug Delivery & Formulation (2011), 5(3), 188-200

This review details articles and recent patents in an emerging topic called powdered form of nano- and microparticles. Solid lipid particles were developed in the early 1990s and since, they have been ... [more ▼]

This review details articles and recent patents in an emerging topic called powdered form of nano- and microparticles. Solid lipid particles were developed in the early 1990s and since, they have been considered as promising drug delivery systems, especially in providing a sustained release profile of the encapsulated drug. This kind of drug delivery system has several advantages, due to its physiological composition. It is generally well tolerated by the human body and are relatively stable during storage in comparison with other carriers like liposomes. The description of these powdered lipid particles, their different production processes and their applications are the focus of the article. [less ▲]

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See detailSkin penetration behaviour of liposomes as a function of their composition
Gillet, Aline ULg; Lecomte, Frédéric ULg; Hubert, Pascale ULg et al

in European Journal of Pharmaceutics & Biopharmaceutics (2011), 79

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See detailNear infrared and Raman spectroscopy as Process Analytical Technology tools for the manufacturing of silicone-based drug reservoirs
Mantanus, Jérôme ULg; Rozet, Eric ULg; Van Butsele, K. et al

in Analytica Chimica Acta (2011), 699

Using Near Infrared (NIR) and Raman spectroscopy as PAT tools, 3 critical quality attributes of a silicone-based drug reservoir were studied. First, the Active Pharmaceutical Ingredient (API) homogeneity ... [more ▼]

Using Near Infrared (NIR) and Raman spectroscopy as PAT tools, 3 critical quality attributes of a silicone-based drug reservoir were studied. First, the Active Pharmaceutical Ingredient (API) homogeneity in the reservoir was evaluated using Raman spectroscopy (mapping): the API distribution within the industrial drug reservoirs was found to be homogeneous while API aggregates were detected in laboratory scale samples manufactured with a non optimal mixing process. Second, the crosslinking process of the reservoirs was monitored at different temperatures with NIR spectroscopy. Conformity tests and Principal Component Analysis (PCA) were performed on the collected data to find out the relation between the temperature and the time necessary to reach the crosslinking endpoints. An agreement was found between the conformity test results and the PCA results. Compared to the conformity test method, PCA had the advantage to discriminate the heating effect from the crosslinking effect occurring together during the monitored process. Therefore the 2 approaches were found to be complementary. Third, based on the HPLC reference method, a NIR model able to quantify the API in the drug reservoir was developed and thoroughly validated. Partial Least Squares (PLS) regression on the calibration set was performed to build prediction models of which the ability to quantify accurately was tested with the external validation set. The 1.2 % RMSEP of the NIR model indicated the global accuracy of the model. The accuracy profile based on tolerance intervals was used to generate a complete validation report. The 95 % tolerance interval calculated on the validation results indicated that each future result will have a relative error below ±5 % with a probability of at least 95 %. In conclusion, 3 critical quality attributes of silicone-based drug reservoirs were quickly and efficiently evaluated by NIR and Raman spectroscopy. [less ▲]

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See detailOptimisation and validation of a fast HPLC method for the quantification of sulindac and its related impurities
Krier, Fabrice ULg; Brion, Michaël; Debrus, Benjamin ULg et al

in Journal of Pharmaceutical & Biomedical Analysis (2011), 54

The European Pharmacopoeia describes a liquid chromatography (LC) method for the quantification of sulindac, using a quaternary mobile phase including chloroform and with a rather long run time. In the ... [more ▼]

The European Pharmacopoeia describes a liquid chromatography (LC) method for the quantification of sulindac, using a quaternary mobile phase including chloroform and with a rather long run time. In the present study, a new method using a short sub-2μm column, which can be used on a classical HPLC system, was developed. The new LC conditions (without chloroform) were optimised by means of a new methodology based on design of experiments in order to obtain an optimal separation. Four factors were studied: the duration of the initial isocratic step, the percentage of organic modifier at the beginning of the gradient, the percentage of organic modifier at the end of the gradient and the gradient time. The optimal condition allows the separation of sulindac and of its 3 related impurities in six minutes instead of 18 min. Finally, the method was successfully validated using an accuracy profile approach in order to demonstrate its ability to accurately quantify these compounds. [less ▲]

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See detailCellular uptake of long-circulating pH-sensitive liposomes: evaluation of the liposome and its encapsulated material penetration in cancer cells
Ducat, Emilie ULg; Deprez, Julie ULg; Peulen, Olivier ULg et al

in Drug Discovery Today (2010, December), 15(23-24), 1079-1114

Print 3G, a peptidic antagonist of oncoprotein involved in breast cancer, could reduce the angiogenic development of breast tumors, leading to tumor dormancy. The necessity of intravenous administration ... [more ▼]

Print 3G, a peptidic antagonist of oncoprotein involved in breast cancer, could reduce the angiogenic development of breast tumors, leading to tumor dormancy. The necessity of intravenous administration of Print 3G led to the development of long-circulating liposomes as drug carriers. Pegylated liposomes, too large to be collected by fenestrated organs, accumulate passively in solid tumors thanks to the EPR effect. The strategy was to combine the protective properties of PEG with the transfection properties of pH-sensitive lipids which could promote the uptake of liposomes by cells and avoid lysosomal sequestration and degradation of entrapped materials such as peptides. In this study, we compare two formulations in terms of cellular uptake using confocal microscopy. The first one is composed of SPC:CHOL:mPEG-750-DSPE (47:47:6), used as "standard" liposomes, and the second one of DOPE:CHEMS:CHOL:mPEG750-DSPE (43:21:30:6), used as pH-sensitive liposomes. First, we evaluated the penetration of an encapsulated model molecule, calcein, in Hs578t human breast cancer epithelial cells. When calcein was encapsulated in standard liposomes, its penetration was effective only in few cells. On the contrary, a majority of cells were fluorescent when calcein-loaded pH-sensitive liposomes were applied for 3 hours on cells. Secondly, we studied the penetration of liposomes themselves in Hs578t cells using 25-[(nitrobenzoxadiazolyl)methylamino]nor-cholesterol (NBD-CHOL) as a fluorescent marker of the phospholipid membrane. The obtained results were comparable to those obtained with calcein: a higher penetration of liposome was observed for pH-sensitive liposomes. Finally, the cellular uptake of liposomes using both NBD-CHOL and rhodamine encapsulated in the inner cavity of vesicles was evaluated with Hs578t cells and compared with WI26 human diploid lung fibroblast cells. Thanks to this experiment, we could follow simultaneously the cell distribution of the encapsulated material and of the liposome itself. Confocal pictures obtained with pH-sensitive liposomes on both WI26 and Hs578t cells allow us to visualize the co-localized red and green colors of rhodamine and NBD-CHOL, with a higher concentrated area near the nucleus. In comparison with "standard" liposomes, we observed a higher penetration of the encapsulated material and of the liposome itself in breast cancer cells. Moreover, we visualized a colocalization near the nucleus of liposomes components. Concerning results obtained with fibroblastic cells, there was no difference in terms of cellular uptake between the two formulations. In perspective, we would like to compare these results, obtained with model molecules, with experiments performed with biotinylated Print 3G to assess its cellular distribution. Moreover, it would be interesting to correlate results obtained with confocal microscopy with a possible increase of the peptide efficacy against cancer cells when it is encapsulated in long-circulating pH-sensitive liposomes. [less ▲]

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See detailPEPTIDE-LOADED LIPOSOMES AGAINST BREAST CANCER: EFFECTIVE PENETRATION IN CELLS OF LONG CIRCULATING pH-SENSITIVE VESICLES
Ducat, Emilie ULg; Deprez, Julie ULg; Peulen, Olivier ULg et al

Poster (2010, October)

Purpose: Print3G, a peptidic antagonist of oncoprotein involved in breast cancer, could reduce the angiogenic development of breast tumors. The necessity of intravenous administration of Print3G led to ... [more ▼]

Purpose: Print3G, a peptidic antagonist of oncoprotein involved in breast cancer, could reduce the angiogenic development of breast tumors. The necessity of intravenous administration of Print3G led to the development of liposomes as drug carriers, combining the protective properties of PEG with the transfection properties of pH-sensitive lipids. The purpose of this work is to compare pegylated pH-sensitive liposomes with a classical formulation of long-circulating liposomes in terms of cellular uptake. Methods: Classical liposomes (SPC:CHOL:mPEG-750-DSPE (47:47:6 mol/mol)) and pH-sensitive liposomes (DOPE:CHEMS:CHOL: mPEG750-DSPE (43:21:30:6 mol/mol)) were compared in terms of size, charge, stability, pH-sensitivity and toxicity by inhibition of cell proliferation. Finally, confocal microscopy was used to study the cellular uptake of liposomes by three cell lines (Hs578t, WI-26 and MDA-MB-231), using 25-nitrobenzoxydiazol-cholesterol as a fluorescent marker of the vesicular membrane and rhodamine in the inner cavity of liposomes. Results: Sizes of 162.8 ± 4.6 nm and zeta potential of -9.3 ± 1.2 mV were obtained for standard liposomes (n=3) while the obtained values for pH-sensitive liposomes (n=3) were respectively of 184.8 ± 3.2 nm and -19.5 ± 2.6 mV. The two formulations were comparable in terms of shape and stability. Concerning the pH-sensitivity study, a significantly higher leakage of the encapsulated material was observed at pH 5 for pH-sensitive liposomes. Confocal pictures obtained with these vesicles on the three cell lines allowed us to visualize the colocalized red and green color with a higher concentration near the nucleus. Conclusion: Long circulating pH-sensitive liposomes are promising drug delivery systems in terms of cellular uptake. Experiments will be performed with biotinylated Print3G to assess its cellular distribution. Moreover, the accumulation of this formulation in breast tumor will be evaluated by in vivo studies. [less ▲]

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See detailInterest of vesicular systems in dermal drug delivery
Gillet, Aline ULg; Lecomte, Frédéric ULg; Hubert, Pascale ULg et al

Poster (2010, October)

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See detailNIR AND RAMAN SPECTROSCOPY AS PAT TOOLS FOR THE MANUFACTURING OF SILICONE-BASED DRUG RESERVOIRS
Mantanus, Jérôme ULg; Ziemons, Eric ULg; Van Butsele, Kathy et al

Conference (2010, September 24)

Detailed reference viewed: 124 (30 ULg)