© CEA Tous droits réservés. Toute reproduction totale ou partielle sur quelque support que ce soit ou utilisation du contenu de ce document est interdite sans l’autorisation écrite préalable du CEA All rights reserved. Any reproduction in whole or in part on any medium or use of the information contained herein is prohibited without the prior written consent of CEA New Lipid Nanoparticles Formulations for Imaging and Drug delivery purposes and Drug delivery purposes Thomas Delmas 1, Fabrice P. Navarro 1, Isabelle Texier 1, Jérôme Bibette 2, Françoise Vinet 1, Anne Claude Couffin 1 1. DTBS/LETI-Minatec, CEA Grenoble, 17 rue des Martyrs, Grenoble – France 2. ESPCI, Laboratoire Colloïdes et matériaux divisés, UMR 7612, 10 rue Vauquelin, Paris - France References: [1] Lundqvist, M. et al. PNAS 105 (2008) [2] Tbata, Y. et al. J. Control Release 50 (1998) [3] zur Mühlen, A. et al. Eur. J. Pharm. Biopharm. 454 (1998) [4] Müller, R. H. et al. Int. J. Pharm. 242 (2002) [5] Uner, M. Pharmazie 61 (2006) 5 Varying LNP internal composition may be the way to tune the encapsulation and the release behavior of the nanocarrier. Increasing the internal weight fraction of wax lead to smaller particles (Fig. 6). Figure 6 : Effect of core composition on LNP size Figure 4 : F50 standard formulation Figure 5 : Standard formulations FXX: physicochemical properties Further studies will be envisioned: - LNP biodistribution recording using fluorescence imaging - Surface chemistry modification for improving particle targeting and internalisation - Correlation between the internal physical state of LNP and their encapsulation/release properties Optimisation: The model was then used to propose formulations giving monodisperse populations of specific size. Standard formulations with different sizes (30, 50, 80, 100, 120 nm) were isolated to study the effect of particle size on biological interactions, biodistribution and encapsulation/release properties (Fig. 5). Results displayed thereafter focused on the 50nm formulation, called F50 (Fig. 4). Nanomedicine is the use of nanotechnology for medical applications. In this field, drug delivery and in vivo imaging show great promises through the use of nanoparticulate systems as nanocarriers for the protection and targeting of active pharmaceutical ingredients (API) and/or molecular contrast agents. Among a wide variety of nanocargos, Lipid NanoParticles (LNP) present numerous advantages over other formulations. These nanocarriers are biocompatible, biodegradable, allow controlled release and can easily be produced by versatile and up-scalable processes. In this work, we investigated the physicochemistry of LNP to propose optimised formulations for API and/or dye encapsulation. The size will be critical when considering biological interactions [1] and targeting (EPR effect) [2], but may also affect release profiles [3]. LNP core composition should also impact the release properties [4]. Meanwhile, the size distribution will affect LNP physical stability: the more monodisperse the dispersion, the highest the physical stability [5]. Design definition: An experimental design was used to model the physicochemical behaviour of the LNP system. Its definition is summarized in Fig. 2. To conclude, we designed and characterised ready made lipid nanoparticles. Being able to incorporate a wide range of lipophilic molecules, LNP could be foreseen as a nanoplatform for imaging and drug delivery purposes through fluorophore and/or API encapsulation. The large flexibility of LNP formulation should allow their characteristics to be tuned to obtain optimised encapsulation and/or release properties. Figure 2 : Variables defining the experimental design approach Model: The model was constructed on a quadratic design with main effects. The relevance of the diameter model is illustrated in Fig. 3. The model diameter is thus reliable for LNP of sizes ranging from 20 to 120nm. The model regression coefficients are higher than 0.85 (R²=0.90 / R²adjusted = 0.88). Limits (%w/w) Input variables: LowHigh Aqueous phase (PBS 1X) 5095 Lipid mixture (25%oil+75%wax) 530 Lipophilic surfactant (Lipoid S75) 530 Hydrophilic surfactant (Myrj52) 575 Output parameters: Quantitative: (DLS) Size (nm) Polydispersity (UA) Qualitative: (comparative scale) Homogeneity Transparency Viscosity 82 trials Figure 7 : Cell viability assay (Abbreviation: CTRL, control) Acknowledgments: We thank Dr F. De Crecy and Pr P. Ozil for their help for the experimental design Hydrophilic surfactant Hydrophobic surfactant Fluorophore and/or Drug Oil + Wax Figure 1 : LNP definition Figure 3 : Relevance of the diameter model: Normal plot and dispersion analysis Externally studentised residuals Normal % probability Total dispersion (all dp model) Dispersion for dp model ≤ 120nm Dp predicted (nm) Dp experimental (nm) Dp predicted (nm) Normal plot of residuals Diametre (nm) Vector molecule [ Mean ± standard deviation (n=5) / * ND=Not determined ] The LNP cytotoxicity was evaluated by a cell viability assay (ViaCount®). Murine fibroblasts (NIH-3T3 cell line) were incubated in presence of LNP for 24h at 37°C (Fig. 7). LNP displayed no cytotoxicity for concentrations up to 1000 µg/ml CTRLLNP Percent viability [ Mean ± standard deviation (n=3)] FXX Size (nm)Polydispersity (AU) Zeta Potential (mV) dp modeldp exp (n=5)PDI modelPDI exp (n=5) F ± ± 0.034ND* F ± 2, ± 0, ± 2.5 F ± ± ± 1.1 F ± ± ± LNP Formulation 1.Introduction 5. Conclusion & Perspectives 3. Effect of LNP core composition4. Cytotoxicity