La toxicité cutanée due à l administration de l ERBITUX dans les cancers colorectaux métastatiques

MONTPELLIER-BU Pharmacie (341722105) / SudocSudocFranceF

Powdered lipid nano and microparticles : production and applications

peer reviewedThis 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

Coumarins as factor XIIa inhibitors:Potency and selectivity improvements using a fragment-based strategy

Previously, we described weak coumarin inhibitors of factor XIIa, a promising target for artificial surface-induced thrombosis and various inflammatory diseases. In this work, we used fragment-based drug discovery approach to improve our coumarin series. First, we screened about 200 fragments for the S1 pocket. The S1 pocket of trypsin-like serine proteases, such as factor XIIa, is highly conserved and is known to drive a major part of the association energy. From the screening, we selected fragments displaying a micromolar activity and studied their selectivity on other serine proteases. Then, these fragments were merged to our coumarin templates, leading to the generation of nanomolar inhibitors. The mechanism of inhibition was further studied by mass spectrometry demonstrating the covalent binding through the formation of an acyl enzyme complex. The most potent compound was tested in plasma to evaluate its stability and efficacy on coagulation assays. It exhibited a plasmatic half-life of 1.9 h and a good selectivity for the intrinsic coagulation pathway over the extrinsic one.</p

Cationic Liposomes Carrying siRNA: Impact of Lipid Composition on Physicochemical Properties, Cytotoxicity and Endosomal Escape

Abstract: In recent year, cationic liposomes have gained a lot of attention for siRNA delivery. Despite this, intracellular barriers as endosomal escape and cytosolic delivery of siRNA still represent a challeng, as well as the cytotoxicity due to cationic lipids. To address these issues, we developed four liposomal formulations, composed of two different cationic lipids (DOTAP and DC-Cholesterol) and different ratio of co-lipids (cholesterol and DOPE). The objective is to dissect these impacts on siRNA efficacy and cytotoxicity. Liposomes were complexed to siRNA at six different N/P molar ratios, physico-chemical properties were characterized, and consequently, N/P 2.5, 5 and 10 were selected for in vitro experiments. We have shown that cytotoxicity is influenced by the N/P ratio, the concentration of cationic lipid, as well as the nature of the cationic lipid. For instance, cell viability decreased by 70% with liposomes composed of DOTAP/Cholesterol/DOPE 1/0.75/0.5 at a N/P ratio 10, whereas the same formulation at a N/P ratio of 2.5 was safe. Interestingly, we have observed differences in terms of mRNA knock-down efficiency, whereas the transfection rate was quite similar for each formulation. Liposomes containing 50% of DOPE induced a mRNA silencing of around 80%. This study allowed us to highlight crucial parameters in order to develop lipoplexes which are safe, and which induce an efficient intracytoplasmic release of siRNA

Cationic Liposomes Carrying siRNA: Impact of Lipid Composition on Physicochemical Properties, Cytotoxicity and Endosomal Escape

In recent year, cationic liposomes have gained a lot of attention for siRNA delivery using different local routes of administration as the vaginal [1] or the pulmonary routes. However, lipoplexes have to face several biological and intracellular barriers before releasing the genetic cargo. In this study, we focus our effort on intracellular barriers and more specifically on endosomal escape and cytosolic delivery of siRNA as well as on the cytotoxicity due to cationic lipids. Indeed, we have previously demonstrated that the surface charge of liposomes composed of the cationic lipid DOTAP is correlated to the induction of cytotoxicity [2]. In the present study, we have investigated the impact of different cationic lipids and co-lipids on the cytotoxicity and also on the endosomal escape of siRNA by flow cytometry, qRT-PCR and Western Blot assays [3]. To address these issues, we developed four liposomal formulations composed of two different cationic lipids (DOTAP and DC-Cholesterol) and different ratio of co-lipids (cholesterol and DOPE). Formulations were DOTAP/Cholesterol/DOPE 1/0.75/0.5, DOTAP/Cholesterol/DOPE 1/0.5/0.5, DOTAP/DOPE 1/1 and DC-Cholesterol/DOPE 1/1. Each type of liposomes were complexed to siRNA at six different N/P molar ratios and physico-chemical properties were characterized in terms of Z-average size, Zeta potential and complexation efficiency by gel retardation assay. Consequently, three N/P ratios (2.5, 5 and 10) were selected for in vitro experiments on A549 cells. First, we studied the cell viability of A549 cells treated during 24 h with liposomes complexed to inactive siRNA at different N/P molar ratios at siRNA concentrations of 40 and 100 nM. We have shown that the cytotoxicity is influenced by the N/P ratio, the concentration of cationic lipid as well as the nature of the cationic lipid. Secondly, the cellular uptake were evaluated by flow cytometry using the dry Trypan Blue® to quench the external fluorescence. Despite the fact the transfection rate were not significantly different, the mRNA knock-down efficiency were not similar between formulations. Liposomes containing 50% of DOPE induced a mRNA silencing of around 80% as well as the protein knock-down. This study allowed to highlight crucial parameters in order to develop lipoplexes which are safe and induce an efficient intracytoplasmic release of siRNA. Acknowledgments: The authors thank the Belgium National Fund for Scientific Research (FNRS, http://www.frs-fnrs.be) –Télévie for financial support and the Giga Cell Imaging and Flow Cytometry Platform for their collaboration. Anna Lechanteur is a FNRS-Télévie post-doctoral researcher. Amandine Duchemin is a FRIA FNRS Fellow. Denis Mottet is a FNRS Research Associate. References: 1. Lechanteur, A., Furst, T. Delvenne, P. et al., Promoting vaginal distribution of E7 and MCL-1 siRNA-silencing nanoparticles for cervical cancer treatment Molecular Pharmaceutics, 2017. 14: p. 1706-1717. 2. Lechanteur, A., Furst, T. Evrard, B. et al., PEGylation of lipoplexes: The right balance between cytotoxicity and siRNA effectiveness. Eur J Pharm Sci, 2016. 93: p. 493-503. 3. Lechanteur, A., Sanna, V. Duchemin, A. et al., Cationic Liposomes Carrying siRNA: Impact of Lipid Composition on Physicochemical Properties, Cytotoxicity and Endosomal Escape. Nanomaterials (Basel), 2018. 8(270): p. 1-12

A simple calibration approach based on film-casting for confocal Raman microscopy to support the development of a Hot-Melt Extrusion process

When developing a new formulation, the development, calibration and validation steps of analytical methods based on vibrational spectroscopy are time-consuming. For each new formulation, real samples must be produced and a “reference method” must be used in order to determine the Active Pharmaceutical Ingredient (API) content of each sample. To circumvent this issue, the paper presents a simple approach based on the film-casting technique used as a calibration tool in the framework of hot-melt extrusion process. Confocal Raman microscopic method was successfully validated for the determination of itraconazole content in film-casting samples. Then, hot-melt extrusion was carried out to produce real samples in order to confront the results obtained with confocal Raman microscopy and Ultra High Performance Liquid Chromatography (UHPLC). The agreement between both methods was demonstrated using a comparison study based on the Bland and Altman’s plot

Increase over time of antibody levels 3 months after a booster dose as an indication of better protection against Omicron infection

International audienceThe third, "booster", vaccination increases the overall immune response against SARS-CoV-2 variants. However, after the initial peak at around 3 weeks post-vaccination, anti-spike antibody levels decline. Post-booster kinetics of cellular response has been less investigated and there is no documented evidence of a true boosting effect. Furthermore, multiple studies underline the less effective immune responses against Omicron, the latest variant of concern, at both humoral and cellular levels. In this letter, we analyse humoral (anti-RBD IgG levels) and cellular (IFN-? release assay) immune response in 205 health care workers 3 weeks and 3 months after administration of an mRNA-based booster dose, either mRNA-1273 or BNT162b2. Since all subjects were SARS-CoV-2 infection-naive, we also looked at the incidence of Omicron infection between 3 and 6 months post-booster.At both timepoints, 3x mRNA-1273 vaccination had the highest overall antibody and IFN-? levels, followed by 3x BNT162b2 vaccination and heterologous mRNA-based regimens. Heterologous ChAdOx1-mRNA-based regimen had the lowest antibody levels while cellular response equal to that of 3x BNT162b2 vaccination and heterologous mRNA-based regimens. Our results show that both humoral and cellular responses waned at 3 months for all vaccination regimens. However, we identified three trajectories of dosage variation. Interestingly, the subgroup of subjects with increasing anti-RBD IgG levels over time had a lower incidence of Omicron infection. Whether increasing humoral response at 3 months post-booster is more indicative of protection than a high initial peak remains to be confirmed in a larger cohort

Decline of Humoral and Cellular Immune Responses Against SARS-CoV-2 6 Months After Full BNT162b2 Vaccination in Hospital Healthcare Workers

International audienceClinical trials and real-world evidence on COVID-19 vaccines have shown their effectiveness against severe disease and death but the durability of protection remains unknown. We analysed the humoral and T-cell immune responses in 110 healthcare workers (HCWs) vaccinated according to the manufacturer’s recommended schedule of dose 2 three weeks after dose 1 from a prospective on-going cohort in early 2021, 3 and 6 months after full vaccination with the BNT162b2 mRNA vaccine. Anti-RBD IgG titres were lower in HCWs over 60 years old 3 months after the second dose (p=0.03) and declined in all the subjects between 3 and 6 months with a median percentage change of -58.5%, irrespective of age and baseline comorbidities. Specific T-cell response measured by IGRA declined over time by at least 42% (median) in 91 HCWs and increased by 33% (median) in 17 others. Six HCWs had a negative T-cell response at 6 months. Ongoing follow-up should provide correlates of long-term protection according to the different immune response profiles observed. COVIDIM study was registered under the number NCT04896788 on clinicaltrials.gov

Comparative T and B immune responses of four different anti-COVID-19 vaccine strategies 6 months after vaccination

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Association between transportation noise exposure and type 2diabetes risk in the French E3N cohort

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