References of "Delattre, Luc"
     in
Bookmark and Share    
Full Text
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 ▲]

Detailed reference viewed: 87 (31 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 37 (3 ULg)
Full Text
Peer Reviewed
See detailUnsuccessful Induction of Endometriosis in Female Rhesus Macaques (Macaca mulatta).
Defrère, S.; Squifflet, J.; Lousse, J. C. et al

in Gynecologic & Obstetric Investigation (2008), 66(2), 84-90

Background/Aims: The aim of this study was to induce endometriosis in female rhesus macaques (Macaca mulatta) for research purposes. Methods: Three female monkeys from 4 to 4.5 years of age underwent ... [more ▼]

Background/Aims: The aim of this study was to induce endometriosis in female rhesus macaques (Macaca mulatta) for research purposes. Methods: Three female monkeys from 4 to 4.5 years of age underwent three consecutive attempts at endometriosis induction over an 8-month period: (i) the first attempt involved intravaginal sampling of endometrial tissue and transplantation into the intrapelvic cavity; (ii) the second entailed surgical removal of endometrium after hysterotomy and intra-abdominal placement, and (iii) the third used endometrial mucosa obtained by scraping the uterus after hysterectomy, placed in a surgical pouch created in the retrovesical space (Retzius). In each case, the pelvic cavity was closely inspected after 7, 9, and 6 weeks respectively for the presence of endometriotic lesions, and peritoneal biopsies were performed. Results: Neither macroscopic observation nor histological analysis revealed any endometriotic lesions. Conclusion: This failure to induce endometriosis in female rhesus macaques suggests that this species is not the most efficient experimental model among primates to investigate endometriosis development or treatment. [less ▲]

Detailed reference viewed: 28 (7 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 52 (21 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 40 (10 ULg)
Full Text
Peer Reviewed
See detailValidation of manufacturing process of Diltiazem HCl tablets by NIR spectrophotometry (NIRS)
Bodson, Cédric; Rozet, Eric ULg; Ziemons, Eric ULg et al

in Journal of Pharmaceutical & Biomedical Analysis (2007), 45(2), 356-361

The goal of this study was to apply the Process Analytical Technology FDA's initiative in pharmaceutical tablets manufacturing. Near Infrared Spectrophotometry (NIRS) was used as a non-destructive, very ... [more ▼]

The goal of this study was to apply the Process Analytical Technology FDA's initiative in pharmaceutical tablets manufacturing. Near Infrared Spectrophotometry (NIRS) was used as a non-destructive, very fast technique requiring no sample preparation. Direct compression powder blends containing Diltiazem HCl as a model drug were pressed into tablets for the calibration and the validation steps. First, a partial least squares model was built to calibrate the NIR spectrometer. Then, this model was validated and compared with a validated UV spectrophotometry reference method. For this comparison, the Bland and Altman's statistical method was applied. The manufacturing process was validated by producing three batches at three different concentration levels. The NIR analysis of these batches was performed during 3 days. This study shows that NIRS can be used to validate the whole manufacturing process and not only as an analytical method for tablets assay. NIRS is an interesting tool to show possible variations during the manufacturing process which could lead the finished product to fall outside of specifications. [less ▲]

Detailed reference viewed: 180 (13 ULg)
Full Text
Peer Reviewed
See detailStudy of the relationship between lipid binding properties of cyclodextrins and their effect on the integrity of liposomes
Piel, Géraldine ULg; Piette, Marie ULg; Barillaro, Valery et al

in International Journal of Pharmaceutics (2007), 338(1-2), 35-42

It is well known that cyclodextrins are able to extract lipids constituting membranes, increasing their fluidity and permeability. This behaviour towards biological membranes is directly linked to the ... [more ▼]

It is well known that cyclodextrins are able to extract lipids constituting membranes, increasing their fluidity and permeability. This behaviour towards biological membranes is directly linked to the toxicological effects of methylated cyclodextrins. However, confusion is currently made in the literature between the different methylated cyclodextrin derivatives. Moreover, a new methylated cyclodextrin derivative recently occurred in the market. the Crysmeb (R). We wanted to compare and understand the effect of the most currently used cyclodextrins on a model membrane. We studied the influence of natural cyclodextrins (beta CD and gamma CD), methylated derivatives (2,6-dimethyl-beta CD (Dimeb), 2,3,6-trimethyl-beta CD (Trimeb) and randomly methylated-beta CD (Rameb), as well as the new derivative Crysmeb), hydroxypropylated derivatives (HP beta CD of different substitution degrees and HP gamma CD) and the sulfobutylated derivative (SBE beta CD) on the release of a fluorescent marker encapsulated in the inner cavity of liposomes. It was shown that the observed effect on calcein release can be directly related to the affinity of cyclodextrins for both lipid components of liposomes, cholesterol and phosphatidylcholine. From this relationship, we were able to determine, for each cyclodextrin, a theoretical concentration giving rise to 50% or 100% calcein release. This theoretical concentration was confirmed experimentally. We have also showed that cyclodextrins which provoke calcein release also induce large structure modifications of liposomes. (c) 2007 Elsevier B.V. All rights reserved. [less ▲]

Detailed reference viewed: 38 (11 ULg)
Full Text
Peer Reviewed
See detailSolid lipid microparticles containing the sunscreen agent, octyl-dimethylaminobenzoate: Effect of the vehicle
Tursilli, Rosanna; Piel, Géraldine ULg; Delattre, Luc ULg et al

in European Journal of Pharmaceutics & Biopharmaceutics (2007), 66(3), 483-487

Solid lipid microparticles (SLMs) loaded with the sunscreen agent, octyl-dimethyl amino benzoate (ODAB), were prepared in order to achieve enhanced sunscreen photostability. The microparticles were ... [more ▼]

Solid lipid microparticles (SLMs) loaded with the sunscreen agent, octyl-dimethyl amino benzoate (ODAB), were prepared in order to achieve enhanced sunscreen photostability. The microparticles were produced by the melt dispersion technique using glyceryl behenate as lipidic material and poloxamer 188 as the emulsifier. The obtained SLMs showed proper features in terms of morphology, size distribution (1.67-15.81 mu m) and ODAB loading (16.15 +/- 0.11%, w/w). The sunscreen release from the SLMs was slower than its dissolution rate and the photodecomposition of ODAB was markedly decreased (> 51.3%) by encapsulation into the lipid microparticles. The efficacy of the SLM carrier system was also evaluated after their introduction in model topical formulations (i.e., hydrogel and oil-in-water emulsion). Further in vitro release measurements, performed using Franz diffusion cells with polycarbonate membranes, indicated that the retention capacity of the microparticles was lost after their incorporation into the emulsion, whereas it was retained in the hydrogel. Moreover, the SLMs achieved a reduction of the sunscreen photodegradation in the hydrogel vehicle (the ODAB loss decreased from 87.4% to 59.1%), whereas no significant photoprotective effect was observed in the emulsion. Therefore, the efficacy of the ODAB-loaded SLMs was markedly affected by the vehicle. (c) 2007 Elsevier B.V. All rights reserved. [less ▲]

Detailed reference viewed: 40 (1 ULg)
Full Text
Peer Reviewed
See detailStudy of the interaction between cyclodextrins and liposome membranes: effect on the permeability of liposomes
Piel, Géraldine ULg; Piette, Marie ULg; Barillaro, Valery et al

in Journal of Inclusion Phenomena and Macrocyclic Chemistry (2007, April), 57(1-4), 309-311

We wanted to compare and understand the effect of the most currently used cyclodextrins on a model membrane. We studied the influence of most currently used cyclodextrins on the release of a fluorescent ... [more ▼]

We wanted to compare and understand the effect of the most currently used cyclodextrins on a model membrane. We studied the influence of most currently used cyclodextrins on the release of a fluorescent marker encapsulated in the inner cavity of SUV liposomes. It was shown that the observed effect on calcein release can be directly related to the affinity of cyclodextrins for both lipid components of liposomes, cholesterol and phosphatidylcholine. From this relationship, we were able to determine, for each cyclodextrin, a theoretical concentration giving rise to 50% or 100% calcein release. This theoretical concentration was confirmed experimentally. [less ▲]

Detailed reference viewed: 95 (8 ULg)
Peer Reviewed
See detailEvaluation of the cytotoxicity of cyclodextrins on endothelial cells using MTT assay
Castagne, Delphine ULg; Belhadj Salem, Leila; Delattre, Luc ULg et al

Poster (2007, April)

Detailed reference viewed: 24 (1 ULg)
Full Text
Peer Reviewed
See detailPreparation and evaluation of liposomes encapsulating synthetic MMP inhibitor (Ro 28-2653) - cyclodextrin complexes
Piette, Marie ULg; Castagne, Delphine ULg; Delattre, Luc ULg et al

in Journal of Inclusion Phenomena and Macrocyclic Chemistry (2007, April), 57(1-4), 101-103

In this study, preparation and evaluation of liposomes, intended for intravenous administration, encapsulating synthetic MMP inhibitor (Ro 28-2653) - cyclodextrin complexes were realized. An increase in ... [more ▼]

In this study, preparation and evaluation of liposomes, intended for intravenous administration, encapsulating synthetic MMP inhibitor (Ro 28-2653) - cyclodextrin complexes were realized. An increase in Ro solubility, via formation of binary (Ro/HP beta CD) or ternary (Ro/HP beta CD/L-lysine) complexes, permitted a similar increase in encapsulation efficiency of liposomes (Table 1). Moreover, Ro release kinetics depend on the encapsulation efficiency. [less ▲]

Detailed reference viewed: 79 (9 ULg)
Full Text
Peer Reviewed
See detailStudy of the physicochemical properties in aqueous medium and molecular modeling of tagitinin C/cyclodextrin complexes
Ziemons, Eric ULg; Dive, Georges ULg; Debrus, Benjamin ULg et al

in Journal of Pharmaceutical & Biomedical Analysis (2007), 43(3), 910-919

The inclusion complexes of tagitinin C with beta-, 2,6-di-O-methyl-beta- and gamma-cyclodextrin (CyD) was investigated in aqueous medium. The stoichiometric ratios and stability constants (K(f)) which ... [more ▼]

The inclusion complexes of tagitinin C with beta-, 2,6-di-O-methyl-beta- and gamma-cyclodextrin (CyD) was investigated in aqueous medium. The stoichiometric ratios and stability constants (K(f)) which describe the extent of formation of the complexes have been determined by UV spectroscopy and direct current tast polarography (DC(tast)), respectively. For each complex, a 1:1 molar ratio was formed in solution and the trend of stability constants was K(f) (2,6-di-O-methyl-beta-CyD)>K(f) (gamma-CyD)>K(f) (beta-CyD). The effect of molecular encapsulation on the photochemical conversion of tagitinin C was evaluated. No significant protection efficacy was noticed with beta- and gamma-CyD for the complexed drug with the respect to the free one. On the other hand, the photochemical conversion rate was slowed in presence of 2,6-di-O-methyl-beta-CyD. Data from (1)H NMR and ROESY experiments provided a clear evidence of formation of inclusion complexes. The lactone, the ester and the unsaturated ketone parts of tagitinin C inserted into the wide rim of the CyDs torus. These experimental results were confirmed by the molecular modeling using semiempirical Austin Model 1 (AM1) method. [less ▲]

Detailed reference viewed: 79 (14 ULg)
Full Text
Peer Reviewed
See detailSolid lipid microparticles as a sustained release system for pulmonary drug delivery
Jaspart, Séverine ULg; Bertholet, Pascal; Piel, Géraldine ULg et al

in European Journal of Pharmaceutics & Biopharmaceutics (2007), 65(1), 47-56

The controlled release of drugs for pulmonary, delivery is a research field which has been so far rather unexploited but is currently becoming increasingly attractive. The introduction part of this ... [more ▼]

The controlled release of drugs for pulmonary, delivery is a research field which has been so far rather unexploited but is currently becoming increasingly attractive. The introduction part of this research article first details the potential advantages of solid lipid microparticles (SLMs) as drug carrier compared to liposomes and polymeric microspheres. The aim of this work is to use SLMs to impart a sustained release profile to a model drug, salbutamol acetonide (SA). SA was synthesized from salbutamol in order to increase the lipophilicity of this molecule and thereby to increase its incorporation efficiency into SLMs. SA-loaded SLMs were then produced by a hot emulsion technique followed by high-shear homogenisation and the manufacturing parameters were optimized using the experimental design methodology in order to reach a suitable particle size for pulmonary administration. Scanning electron micrographs showed that SLMs are spherical, have a smooth surface and that SA crystallises outside of the particles when the drug loading is higher than 20%. This was confirmed by X-ray diffraction. SA in vitro release study from SLMs showed that the release rate increased with SA loading but remained in every case lower than the dissolution rate of pure SA. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

Detailed reference viewed: 84 (22 ULg)