References of "Evrard, Brigitte"
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See detailPreparations and characterisations of semi-solid formulations containing a hydrophilic drug for vaginal administration
Coia, Isabelle ULg; Evrard, Brigitte ULg; Piette, Marie ULg

Poster (2009, April 01)

The purpose of this study is to demonstrate the effect of different types of semi-solid formulations (aqueous gels, liquid jellified emulsions and hydrophilic or lipophilic creams) for vaginal ... [more ▼]

The purpose of this study is to demonstrate the effect of different types of semi-solid formulations (aqueous gels, liquid jellified emulsions and hydrophilic or lipophilic creams) for vaginal administration on the release kinetic of a hydrophilic drug. This drug is an acidic and hydrophilic (log P (octanol/water) = -3.3) molecule with an aqueous solubility upper than 170mg/ml at pH 6-8. The formulations characterisations consisted in the in vitro evaluation of the drug release kinetic and the measure of all formulations viscosity as well as the creams stability and emulsions droplets size. [less ▲]

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See detailDéveloppement d'un implant intra-péritonéal contre l'endométriose
Krier, Fabrice ULg; Evrard, Brigitte ULg; Piel, Géraldine ULg et al

Scientific conference (2009, February 03)

Detailed reference viewed: 23 (9 ULg)
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Peer Reviewed
See detailStudy of the cholesterol extraction capacity of β-cyclodextrin and its derivatives, relationships with their effects on endothelial cell viability and on membrane models
Castagne, Delphine ULg; Fillet, Marianne ULg; Delattre, Luc ULg et al

in Journal of Inclusion Phenomena and Macrocyclic Chemistry (2009), 63(3-4), 225-231

Endothelial cells (HUVEC) were treated with β-cyclodextrin and hydroxypropylated or methylated derivatives solutions in order to quantify their cholesterol extraction capacity. Non-toxic concentrations of ... [more ▼]

Endothelial cells (HUVEC) were treated with β-cyclodextrin and hydroxypropylated or methylated derivatives solutions in order to quantify their cholesterol extraction capacity. Non-toxic concentrations of cyclodextrins (CDs) were determined following methyl thiazol tetrazolium (MTT) assays, total protein measurements, morphological observations and trypan blue assays. The residual cholesterol content of cells was measured and the extraction power of CDs compared to results obtained by phase solubility diagrams. Cholesterol was extracted with a dose-response relationship, the lowest residual cholesterol content being obtained with β-CD at 10 mM. Low substituted derivatives (Crysmeb® and hydroxypropyl-β-CD) maintained liposomes integrity (as shown before), were the less cytotoxic and presented the lowest affinity for cholesterol contrary to methylated derivatives with degrees of substitution around 2. [less ▲]

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See detailMoisture content determination of pharmaceutical pellets by near infrared spectroscopy: method development and validation.
Mantanus, Jérôme ULg; Ziemons, Eric ULg; Lebrun, Pierre ULg et al

in Analytica Chimica Acta (2009), 642(1-2), 186-92

The aim of the present study was to develop and validate a near infrared method able to accurately determine a moisture content of pharmaceutical pellets ranging from 1% to 8% in order to check their ... [more ▼]

The aim of the present study was to develop and validate a near infrared method able to accurately determine a moisture content of pharmaceutical pellets ranging from 1% to 8% in order to check their moisture content conformity. A calibration and validation set were designed for the conception and evaluation of the method adequacy. An experimental protocol was then followed, involving two operators, independent production campaign batches and different temperatures for data acquisition. On the basis of this protocol, prediction models based on partial least squares (PLS) regression were then carried out. Conventional criteria such as the R(2), the root mean square errors of calibration and prediction (RMSEC and RMSEP) as well as the number of PLS factors enabled the selection of three preliminary models. However, such criteria did not clearly demonstrate the model's ability to give accurate predictions over the whole analyzed water content range. Consequently, a novel approach based on accuracy profiles which allow the selection of the most fitted model for purpose was used. According to this novel approach, the model using multiplicative scatter correction (MSC) pre-treatment was obviously the most suitable. Indeed, the resulting accuracy profile clearly showed that this model was able to determine moisture content over the range of 1-8% with a very acceptable accuracy. The present study confirmed that NIR spectroscopy could be used in the PAT concept as a non-invasive, non-destructive and fast technique for moisture content determination in pharmaceutical pellets. In addition, facing the limit of the classical and commonly used criteria, the use of accuracy profiles proved to be useful as a powerful decision tool to demonstrate the suitability of the proposed analytical method. [less ▲]

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See detailCHARACTERIZATION AND OPTIMIZATION OF PEPTIDE ENCAPSULATION IN PEGYLATED LIPOSOMES
Ducat, Emilie ULg; Brion, Michael; Evrard, Brigitte ULg et al

Poster (2009)

Purpose: The purpose of this work is to study the peptide encapsulation into PEGylated liposomes. Two formulations (SPC:CHOL:mPEG-750-DSPE (47:47:6) or SPC:CHOL:mPEG-2000-DSPE (47:47:6)) were investigated ... [more ▼]

Purpose: The purpose of this work is to study the peptide encapsulation into PEGylated liposomes. Two formulations (SPC:CHOL:mPEG-750-DSPE (47:47:6) or SPC:CHOL:mPEG-2000-DSPE (47:47:6)) were investigated. Methods: Blank SUV liposomes were prepared by the lipid film hydration and the encapsulation was achieved by applying freeze-thawing cycles. Because many factors may influence peptide entrapment (number of freeze-thawing cycles (NC), lipid concentration (LC), peptide concentration (PC), mixing time (MT) and liposome composition (COMP)), a design of experiment (DOE) was performed. Results: The screening permitted to identify two factors having a positive and significant influence on the encapsulation efficiencies (NC and LC) while the liposome composition had a relatively weak effect. For the second part of the DOE, the positive factors were optimized for liposomes containing mPEG2000. The obtained results revealed a theoretical optimum at 64.75±3.55% when 11 cycles were applied and for the following LC: 36.1mM SPC, 36.1mM CHOL and 4mM mPEG-2000-DSPE. Experimental results showed an encapsulation efficiency of 62.68±2.93%. Conclusion: The DOE led to significant improvement of encapsulation for liposomes containing mPEG2000. Thereafter, an optimization design for liposomes containing mPEG750 will be started. Acknowledgements: This work was supported by the Ministry of the Walloon Region. [less ▲]

Detailed reference viewed: 26 (5 ULg)
See detailFORMULATION OF PEPTIDE-LOADED LIPOSOMES FOR INTRAVENOUS DELIVERY: OPTIMIZATION OF THE ENCAPSULATION EFFICIENCY
Ducat, Emilie ULg; Brion, Michael; Evrard, Brigitte ULg et al

Conference (2009)

Purpose: Print 3G is a peptidic antagonist of oncoprotein involved in breast cancer, containing 25 amino acids. The purpose of this work is to study the peptide encapsulation into PEGylated liposomes ... [more ▼]

Purpose: Print 3G is a peptidic antagonist of oncoprotein involved in breast cancer, containing 25 amino acids. The purpose of this work is to study the peptide encapsulation into PEGylated liposomes composed of SPC:CHOL:mPEG-2000-DSPE (47:47:6). Methods: Loaded unilamellar vesicles were prepared by hydration of lipid film method. Unfortunately, a loss of Print 3G was observed during the different steps of this manufacturing technique giving rise to encapsulation efficiencies (EE) close to 0 %. Thus, the freeze-thawing method was used to enhance the amount of Print 3G encapsulated into blank liposomes prepared using the above procedure. Because many factors may influence the peptide entrapment into the vesicles (number of freeze-thawing cycles (NC), lipid concentration (LC), peptide concentration (PC) and mixing time (MT)), a design of experiment (DOE) was performed (for the screening, a Plackett and Burman plan; for the optimization, a central composite design). EE were calculated in terms of quantity of peptide loaded in liposomes as a function of quantity operated (EEp) or quantity of lipids (EEl). Results: The EE obtained by the freeze-thawing method in standard conditions (Katanasaka, Ida et al., 2008; Maeda, Bharate et al., 2008), amounted to 26.20 ± 7.98 %, n=3 (EEp) and to 0.26 ± 0.074 % (EEl). Among the different considered parameters, the screening permitted to identify two factors having a positive and significant influence on the EE: NC and LC. Concerning the PC and MT, no influence was revealed. For the second part of the DOE, the positive factors were optimized and obtained results revealed a theoretical optimum at 64.75 ± 3.55 % when 11 freeze-thawing cycles were applied (NC) and for the following LC: 36.1 mM SPC, 36.1 mM CHOL and 4mM mPEG-2000-DSPE. The experimental results showed an encapsulation efficiency of 62.68 ± 2.93 %. Photon correlation spectroscopy and freeze-fracture electron microscopy were also realized to examine the liposome integrity, before and after the freeze-thawing cycles. Conclusion: Changing the manufacturing technique permitted a significant encapsulation of Print 3G into liposomes. The DOE led to a significant improvement of encapsulation efficiencies. References: (1) Katanasaka,Y., Ida,T., Asai,T., Maeda,N., Oku,N., 2008. Effective delivery of an angiogenesis inhibitor by neovessel-targeted liposomes. International Journal of Pharmaceutics, 360, 219-224. (2) Maeda,H., Bharate,G.Y., Daruwalla,J., 2008. Polymeric drugs for efficient tumor-targeted drug delivery based on EPR effect. Eur. J Pharm Biopharm. Acknowledgements: This work was supported by the Ministry of the Walloon Region. [less ▲]

Detailed reference viewed: 77 (2 ULg)
Peer Reviewed
See detailCHARACTERIZATION AND OPTIMIZATION OF PEPTIDE ENCAPSULATION IN PEGYLATED LIPOSOMES
Ducat, Emilie ULg; Brion, Michael; Evrard, Brigitte ULg et al

Poster (2009)

Purpose: Print 3G is a peptidic antagonist of oncoprotein involved in breast cancer, containing 25 amino acids. The purpose of this work is to study the peptide encapsulation into PEGylated liposomes. Two ... [more ▼]

Purpose: Print 3G is a peptidic antagonist of oncoprotein involved in breast cancer, containing 25 amino acids. The purpose of this work is to study the peptide encapsulation into PEGylated liposomes. Two formulations composed of SPC:CHOL:mPEG-750-DSPE (47:47:6) or SPC:CHOL:mPEG-2000-DSPE (47:47:6) were investigated. Methods: Unilamellar vesicles containing either mPEG750 or mPEG2000 were prepared by hydration of lipid films method. Unfortunately, a loss of Print 3G was observed during the different steps of this manufacturing technique giving rise to encapsulation efficiencies close to 0 %. Thus, the freeze-thawing method was used to enhance the amount of Print 3G encapsulated into blank liposomes prepared using the above procedure. Because many factors may influence the peptide entrapment into the vesicles (number of freeze-thawing cycles, lipid concentration, peptide concentration, mixing time and liposome composition), a design of experiment was performed (for the screening, a Plackett and Burman plan; for the optimization, a central composite design). Results: The encapsulation efficiencies obtained by the freeze-thawing method in standard conditions, varied between 17.26 ± 0.46 % (n=3) for liposomes containing mPEG750 and 26.20 ± 7.98 % (n=3) for those comprising mPEG2000. Among the different considered factors, the screening permitted to identify two factors having a positive and significant influence on the encapsulation efficiencies: the number of freeze-thawing cycles and the lipid concentration, while the presence of mPEG2000 or mPEG750 had a relatively weak effect on the encapsulation. Concerning the peptide concentration and the mixing time, no influence was revealed. For the second part of the DOE, the positive factors were optimized for the liposomes containing mPEG2000. The obtained results for liposomes containing mPEG2000 revealed a theoretical optimum at 64.75 ± 3.55 % when 11 freeze-thawing cycles were applied and for the following lipid concentrations: 36.1 mM SPC, 36.1 mM CHOL and 4mM mPEG-2000-DSPE. The experimental results showed an encapsulation efficiency of 62.68 ± 2.93 %. Conclusion: Changing the manufacturing technique permitted a significant encapsulation of Print 3G into liposomes. The DOE led to a significant improvement of encapsulation efficiencies for the liposomes containing mPEG2000. Thereafter, an optimization design for liposomes containing mPEG750 will be started. Acknowledgements: This work was supported by the Ministry of the Walloon Region. [less ▲]

Detailed reference viewed: 130 (1 ULg)