Development of a Pig Mammary Epithelial Cell Culture Model as a Non-Clinical Tool for Studying Epithelial Barrier-A Contribution from the IMI-ConcePTION Project.

The ConcePTION project aims at generating further knowledge about the risks related to the use of medication during breastfeeding, as this information is lacking for most commonly used drugs. Taking into consideration multiple aspects, the pig model has been considered by the consortium as the most appropriate choice. The present research was planned to develop an efficient method for the isolation and culture of porcine Mammary Epithelial Cells (pMECs) to study the mammary epithelial barrier in vitro. Mammary gland tissues were collected at a local slaughterhouse, dissociated and the selected cellular population was cultured, expanded and characterized by morphology, cell cycle analysis and immunophenotyping. Their ability to create a barrier was tested by TEER measurement and sodium fluorescein transport activity. Expression of 84 genes related to drug transporters was evaluated by a PCR array. Our results show that primary cells express epithelial cell markers: CKs, CK18, E-Cad and tight junctions molecules ZO-1 and OCL. All the three pMEC cellular lines were able to create a tight barrier, although with different strengths and kinetics, and express the main ABC and SLC drug transporters. In conclusion, in the present paper we have reported an efficient method to obtain primary pMEC lines to study epithelial barrier function in the pig model.

Animal Models for In Vivo Lactation Studies: Anatomy, Physiology and Milk Compositions in the Most Used Non-Clinical Species: A Contribution from the ConcePTION Project.

The present review aims to summarize the main features of mammary gland anatomy, and the physiology of lactation and colostrum/milk in the most commonly used animal species for regulatory toxicity. The final goal is the selection of a preferred animal species to be enrolled in studies investigating the potential transfer of drugs and exogenous molecules through milk, within the Innovative Medicines Initiative (IMI) funded project ConcePTION. Reference data regarding humans were also collected and analyzed in order to highlight critical similarities and differences with the studied species. Additional practical considerations were also taken into account, such as ethical consideration regarding the chosen species which affects the group size, financial implications and technical feasibility of lactation trials (e.g., ease of sampling, volume of sampling, husbandry requirements and scientific recognition). In conclusion, the present analysis of the literature confirms the complexity of the decisional process behind the choice of an animal model for in vivo trials. For some of the evaluated species, data were either poor or missing, highlighting the necessity to generate more physiological background studies for species that are routinely used in laboratory settings. Overall, when taking into consideration ethical factors, feasible group size, milk volume and ease of milk collection, and physiological similarities with humans, minipigs seem to represent the most appropriate choice.

A comprehensive review on non-clinical methods to study transfer of medication into breast milk - A contribution from the ConcePTION project.

Breastfeeding plays a major role in the health and wellbeing of mother and infant. However, information on the safety of maternal medication during breastfeeding is lacking for most medications. This leads to discontinuation of either breastfeeding or maternal therapy, although many medications are likely to be safe. Since human lactation studies are costly and challenging, validated non-clinical methods would offer an attractive alternative. This review gives an extensive overview of the non-clinical methods (in vitro, in vivo and in silico) to study the transfer of maternal medication into the human breast milk, and subsequent neonatal systemic exposure. Several in vitro models are available, but model characterization, including quantitative medication transport data across the in vitro blood-milk barrier, remains rather limited. Furthermore, animal in vivo models have been used successfully in the past. However, these models don't always mimic human physiology due to species-specific differences. Several efforts have been made to predict medication transfer into the milk based on physicochemical characteristics. However, the role of transporter proteins and several physiological factors (e.g., variable milk lipid content) are not accounted for by these methods. Physiologically-based pharmacokinetic (PBPK) modelling offers a mechanism-oriented strategy with bio-relevance. Recently, lactation PBPK models have been reported for some medications, showing at least the feasibility and value of PBPK modelling to predict transfer of medication into the human milk. However, reliable data as input for PBPK models is often missing. The iterative development of in vitro, animal in vivo and PBPK modelling methods seems to be a promising approach. Human in vitro models will deliver essential data on the transepithelial transport of medication, whereas the combination of animal in vitro and in vivo methods will deliver information to establish accurate in vitro/in vivo extrapolation (IVIVE) algorithms and mechanistic insights. Such a non-clinical platform will be developed and thoroughly evaluated by the Innovative Medicines Initiative ConcePTION.

Chitosan/carboxymethylcellulose-stabilized poly(lactide-co-glycolide) particles as bio-based drug delivery carriers.

Poly(lactide-co-glycolide) (PLGA) colloidal particles stabilized by complexes of two oppositely charged polysaccharides, chitosan (cationic, CS) and sodium carboxymethylcellulose (anionic, NaCMC), were fabricated. Dichloromethane containing dissolved PLGA was first emulsified in an aqueous phase containing mixtures of CS and NaCMC. Evaporation of dichloromethane from the resulting emulsion led to CS/NaCMC-covered-PLGA particles. CS and NaCMC contents affected the short-term stability of PLGA particles and also their intrinsic characteristics. The particles displayed pH-dependent characteristic. Zeta potential varied from +54 to -50 mV when pH was varied from 3 to 10. CS/NaCMC-covered-PLGA particles showed colloidal stability, over a wider pH range as compared to CS-covered-PLGA particles. Curcumin, a model hydrophobic drug, was encapsulated into the particles up to 10 wt% of PLGA. The CS/NaCMC-covered-PLGA particles loaded with curcumin showed delayed release in mildly acidic conditions and faster release in neutral and basic conditions. Cytotoxicity experiments were carried out with human colorectal carcinoma cells.

Encapsulation of monomyristin into polymeric nanoparticles improved its in vitro antiproliferative activity against cervical cancer cells.

The cytotoxicity of monomyristin (MM), a monoacylglycerol, was investigated against cervical cancer cells (HeLa) and two normal cells (Vero and endometrial epithelial cells). MM exhibited cytotoxicity specifically to HeLa cells and not against normal cells except at the highest investigated doses (> 500 µg/mL). MM was showed to increase apoptotic dead cells by intrinsic mitochondrial pathway. To overcome the poor water solubility of MM and increase its efficacy against HeLa cells, MM was encapsulated into dextran-covered polylactide (PLA) nanoparticles (NPs). NPs comprised a PLA core which encapsulated MM and a superficial layer of dextran loops which was used for conjugating a protein, transferrin (Tf), known to be overexpressed on cancer cells' surface. Encapsulation of MM into NPs increased its cytotoxicity against HeLa cells at lower doses of MM than free MM. Additionally, the presence of conjugated Tf further increased the cytotoxicity of MM against HeLa cells as compared to non-conjugated NPs. Remarkably, both conjugated and non-conjugated MM loaded NPs were safe to normal cells (Vero and endometrial).

Stability of a biodegradable microcarrier surface: physically adsorbed versus chemically linked shells.

Mesenchymal stem cells (MSCs) have gained increasing interest for tissue engineering and cellular therapy. MSC expansion on microcarriers (MCs) in stirred bioreactors has emerged as an attractive method for their scaled up production. Some MCs have been developed based on polyesters as a hydrophobic biodegradable core. However, most of these MCs are formulated by an emulsion/organic solvent evaporation (E/E) process using poly(vinyl alcohol) as a shell steric stabilizer, which is biocompatible but not degradable in vivo. Moreover, in most of these MCs, the polymer shell is only physically adsorbed at the particle surface. To the best of our knowledge, no study deals with the stability of such a shell when the MCs are in contact with competitive surfactants or with proteins contained in the culture medium. In this study, fully in vivo bioresorbable dextran-covered polylactide-based MCs were formulated using an E/E process, which allowed to control their surface chemistry. Different dextran derivatives with alkyne or ammonium groups were firstly synthesised. Then, on the one hand, some MCs (non-clicked MCs) were formulated with a physically adsorbed polysaccharide shell onto the core. On the other hand, the polysaccharide shell was linked to the core via in situ CuAAC click-chemistry carried out during the E/E process (clicked MCs). The stability of such coverage was first studied in the presence of competitive surfactants (sodium dodecyl sulfate-SDS, or proteins contained in the culture medium) using nanoparticles (NPs) exhibiting the same chemical composition (core/shell) as MCs. The results revealed the total desorption of the dextran shell for non-clicked NPs after treatment with SDS or the culture medium, while this shell desorption was greatly decreased for clicked NPs. A qualitative study of this shell stability was finally carried out on MCs formulated using a new fluorescent dextran-based surfactant. The results were in agreement with those observed for NPs, and showed that non-clicked MCs are characterized by poor shell stability in contact with a competitive surfactant, which could be quite an issue during MSC expansion. In contrast, clicked MCs possess better shell stability, which allow a better control of the MC surface chemistry, especially during cell culture.

Nanoparticulate delivery systems for alkyl gallates: Influence of the elaboration process on particle characteristics, drug encapsulation and in-vitro release.

PLA nanoparticles loaded with n-alkyl gallates (AGs) were prepared either by nanoprecipitation (NP) or by O/W emulsion/solvent evaporation (E/SE). A nonionic hydrophobically modified polysaccharide was used for surface coverage and for ensuring colloidal stability. Different parameters were systematically assessed to enhance the drug incorporation, with the aim of obtaining monomodal and narrow particle size distributions. The nanoparticles were characterized by 1H NMR, transmission electron microscopy (TEM) and laser light scattering granulometry. The colloidal stability of suspensions was evaluated after incubation in NaCl solutions and was maintained up to 1M NaCl. The mean particle diameter and the width of size distribution were found very similar for both processes (slightly lower diameters when using E/SE) with various drug loadings. The amount of encapsulated AG by E/SE was about twice that encapsulated by NP. The in-vitro release of AG was evaluated under sink conditions and no burst effect was observed. Release curves were successfully modeled using the Fick diffusion model with a constant diffusion coefficient and assuming non-swellable particles. Diffusion coefficients of AG loaded in nanoparticles prepared by NP were higher than those found in nanoparticles elaborated by E/SE.

Amphiphilic Polysaccharides Acting both as Stabilizers and Surface Modifiers during Emulsification in Microfluidic Flow-Focusing Junction.

A continuous emulsion/solvent diffusion process was designed for the preparation of polysaccharide-covered poly(d,l-lactide) (PLA) microparticles. The emulsification step was carried out in a flow-focusing junction where ethyl acetate containing dissolved PLA was dispersed into an aqueous solution of hydrophobically modified dextran. It was demonstrated that poly(dimethylsiloxane) devices could be used for oil-in-water emulsion preparation provided that the microfluidic devices were preconditioned by simply circulating the aqueous phase containing the amphiphilic polysaccharide during a sufficient time (30 h). The adsorption of the polymers at the surface of the channel walls permitted the wetting by the aqueous phase with a hydrophilic character maintained at least throughout 2 months. The preconditioning time was significantly reduced by pretreating the microfluidic device with piranha solution and KOH solution during 15 min each before the circulation of the aqueous solution of dextran derivative. Dextran-covered PLA microparticle aqueous suspensions were produced with well-controlled size distribution. The suspensions could be lyophilized and reconstituted by retrieving the initial size distribution without adding any cryoprotectant. The reported procedure was used for preparing octyl gallate-loaded PLA microparticles.

Discovery of a Dihydroisoquinolinone Derivative (NVP-CGM097): A Highly Potent and Selective MDM2 Inhibitor Undergoing Phase 1 Clinical Trials in p53wt Tumors.

As a result of our efforts to discover novel p53:MDM2 protein-protein interaction inhibitors useful for treating cancer, the potent and selective MDM2 inhibitor NVP-CGM097 (1) with an excellent in vivo profile was selected as a clinical candidate and is currently in phase 1 clinical development. This article provides an overview of the discovery of this new clinical p53:MDM2 inhibitor. The following aspects are addressed: mechanism of action, scientific rationale, binding mode, medicinal chemistry, pharmacokinetic and pharmacodynamic properties, and in vivo pharmacology/toxicology in preclinical species.

Polysaccharide-covered nanoparticles with improved shell stability using click-chemistry strategies.

Dextran-covered PLA nanoparticles have been formulated by two strategies. On one hand, dextran-g-PLA copolymers have been synthesized by click-chemistry between azide-multifunctionalized dextran (DexN3) and alkyne end-functionalized PLA chains (α-alkyne PLA); then nanoprecipitated without any additional surfactants. On the other hand, DexN3 exhibiting surfactant properties have been emulsified with unfunctionalized or α-alkyne PLA, which are dissolved in organic phase with or without CuBr. Depending on the o/w emulsion/evaporation process experimental conditions, dextran-g-PLA copolymers have been produced in situ, by click chemistry at the liquid/liquid interface during the emulsification step. Whatever the process, biodegradable core/shell polymeric nanoparticles have been obtained, then characterized. Colloidal stability of these nanoparticles in the presence of NaCl or SDS has been studied. While the physically adsorbed polysaccharide based shell has been displaced by SDS, the covalently-linked polysaccharide based shell ensures a permanent stability, even in the presence of SDS.

Investigative safety science as a competitive advantage for Pharma.

INTRODUCTION: Following a US National Academy of Sciences report in 2007 entitled "Toxicity Testing of the 21st Century: a Vision and a Strategy," significant advances within translational drug safety sciences promise to revolutionize drug discovery and development. The purpose of this review is to outline why investigative safety science is a competitive advantage for the pharmaceutical industry. AREAS COVERED: The article discusses the essential goals for modern investigative toxicologists including: cross-species target biology; molecular pathways of toxicity; and development of predictive tools, models and biomarkers that allow discovery researchers and clinicians to anticipate safety problems and plan ways to address them, earlier than ever before. Furthermore, the article emphasizes the importance of investigating unanticipated clinical safety signals through a combination of mechanistic preclinical studies and/or molecular characterization of clinical samples from affected organs. EXPERT OPINION: The traditional boundaries between pharma industry teams focusing on safety/efficacy and preclinical/clinical development are rapidly disappearing in favor of translational safety science-centric organizations with a vision of bringing more effective medicines forward safely and quickly. Comparative biology and mechanistic toxicology approaches facilitate: i) identifying translational safety biomarkers; ii) identifying new drug targets/indications; and iii) mitigating off-target toxicities. These value-adding safety science contributions will change traditional toxicologists from side-effect identifiers to drug development enablers.

Evaluation of intra-articular delivery of hyaluronic acid functionalized biopolymeric nanoparticles in healthy rat knees.

The aim of this study is to evaluate the toxicity of nanoparticles of poly(D,L-lactic acid) (PLA) or poly(D,L-lactic-co-glycolic acid) (PLGA) covered by chemically esterified amphiphilic hyaluronate (HA) which will be used for intra-articular injection as a drug carrier for the treatment of arthritis (RA) and/or osteoarthritis (OA). PLA and PLGA are FDA approved polymers that are already used for the preparation of nano or microparticles. HA is a natural polysaccharide already present in the articulations known to interact with the CD44 receptors of the cells (especially chondrocytes). Therefore, we can envisage that the HA covering can improve the interactions between the cells and the nanoparticles, leading to better targeting or biodistribution. The knee of healthy male rats was injected one to two times weekly, with various concentrations of nanoparticles encapsulating Dextran-FITC. The synovial membranes and the patellae were collected aseptically and histologically analyzed to assess the effects and localization of the nanocapsules in the knee joint. We did not observe significant modifications in the synovial membranes (weak hyperplasia) or patellae integrity after local administration of nanodevices into the rats. While we found some nanoparticles in the synovial membrane, none were detected in the patellae. Moreover, the histological observations for patellae were confirmed by radiosulfate intake, which depicted no decrease in proteoglycans biosynthesis in nanoparticles treated animals. Concerning the safety towards synovial membranes, we also had a look at the inflammatory response after injections of nanoparticles covered by amphiphilic HA or polyvinyl alcohol (PVA) by monitoring the mRNA expression levels of some specific early cytokines (IL-1ß and TNF-α). Once again, no differences were observed between the control rats and the rats treated with nanoparticles. Considering these preliminary results obtained in healthy rats, we can establish that neither the amphiphilic HA-covered PLGA nanoparticles nor their degradation products induce major modifications of articular tissues functions, while injected into the knee of healthy rats. These results should be confirmed in OA or RA rat models, in order to confirm that nanoparticles do not worsen already altered (degenerative or inflamed) articular tissues. Once confirmed, such tuneable nanoparticles could be proposed as a safe drug delivery system for the treatment of articular disease, allowing a wide range of encapsulating molecules.

Synthesis and rheological properties of hydrogels based on amphiphilic alginate-amide derivatives.

New amphiphilic derivatives of sodium alginate were prepared by covalent attachment of dodecylamine onto the polysaccharide via amide linkages at different substitution ratios, using 2-chloro-1-methylpyridinium iodide (CMPI) as coupling reagent. The aim was to limit the progressive loss of associative behaviour which occurs in the case of previously described dodecyl ester alginate derivatives due to hydrolysis of ester bonds. A series of hydrogels was obtained which differed by the amount of attached dodecyl tails. The stability and viscoelastic properties were evaluated and compared to those of hydrogels obtained with alginate esters. The observed differences were discussed in relation to the synthesis procedures. The advantages of amide links are underlined, especially with regard to long-term stability of hydrogels.

Hyaluronate-covered nanoparticles for the therapeutic targeting of cartilage.

Hyaluronic acid (HA) has a high affinity for the CD44 receptor present at the surface of articular cells, particularly of chondrocytes. HA-covered polylactide nanoparticles containing bioactive compounds such as HA and chondroitin sulfate (CS) were thus prepared in order to achieve a controlled delivery targeted to cartilage cells after injection near articular alterations/erosions. Such nanoparticles (diameter = 700 nm) were prepared by double emulsion/solvent evaporation, using amphiphilic derivatives of HA, as stabilizer of the secondary emulsion. These nanoparticles were incubated with articular cells, and several tests were carried out. First, they proved that the nanospheres provoked no decrease in cell viability, even after 72 h of contact. Second, a confocal microscopy analysis on fluorescent HA-covered particles showed that they were captured by articular cells, while with those covered with poly(vinyl alcohol), the uptake was far lower. Third, a scattering electron microscopy analysis proved that the HA-coated nanoparticles were localized in the cell intracytoplasmic area.

Seletracetam (UCB 44212).

Better pharmacotherapies for epilepsy are needed for patients who are refractory to or have tolerability difficulties with current treatments. Seletracetam, a new drug in epilepsy development, is a pyrrolidone derivative structurally related to levetiracetam (trade name Keppra). It was discovered because of its high binding affinity to the synaptic vesicle 2A (SV2A) protein, which is now known to be the binding site for this family of compounds. Seletracetam shows very potent seizure suppression in models of acquired or genetic epilepsy, as well as high CNS tolerability in various animal models. Pharmacokinetic studies in animals suggest that seletracetam is rapidly and highly absorbed, with linear and time-independent pharmacokinetics. Seletracetam appears neither to inhibit nor to induce the major human drug metabolizing enzymes, and it demonstrates low plasma protein binding (<10%), which suggests a low potential for drug-drug interactions. Initial studies in humans demonstrated first-order monocompartmental kinetics with a half-life of 8 h and an oral bioavailability of >90%. Studies in healthy volunteers showed that the treatment emergent adverse events were of mild to moderate severity, were mostly of CNS origin and were resolved within 24 h. Altogether, these results suggest that seletracetam represents a promising new antiepileptic drug candidate, one that demonstrates a potent, broad spectrum of seizure protection and a high CNS tolerability in animal models, with initial clinical findings suggestive of straightforward pharmacokinetics and good tolerability.

Surfactive water-soluble copolymers for the preparation of controlled surface nanoparticles by double emulsion/solvent evaporation.

We have already shown that polylactide (PLA) nanoparticles covered with a hydrophilic polymeric layer can be prepared by simple emulsion/solvent evaporation by using amphiphilic copolymers as surfactants during the procedure. The external layer is then constituted by the hydrophilic part of the macromolecular surfactant. This kind of nanospheres is useful for the encapsulation of lipohilic molecules. The use of amphiphilic copolymers as surfactants in the preparation of PLA nanospheres with controlled surface properties, was then applied to the double emulsion/solvent evaporation procedure. The aim was to allow the encapsulation of water-soluble bioactive molecules in PLA particles with controlled surface properties. In this paper, we describe the results obtained with three different water-soluble monomethoxypolyethylene oxide (MPEO)-b-PLA diblock copolymers used as surfactants in the preparation of nanoparticles by double emulsion/solvent evaporation. After organic solvent evaporation, the obtained nanospheres were proved to be really covered by a MPEO layer whose characteristics were determined. It was firstly shown that the MPEO-covered particles did not flocculate at 25 degrees C, even in 4 M NaCl while suspensions of bare nanospheres were destabilized for a NaCl concentration as low as 0.04 M. On the other hand, the suspensions of MPEO-covered nanoparticles in 0.3 M Na2SO4 were found to be very sensitive to temperature as they flocculated at a temperature lying between 45 and 55 degrees C depending on the MPEO-b-PLA composition. This property was attributed to the fact that MPEO is a polymer with a low critical solution temperature. The concentration of MPEO at the nanoparticle surface was then calculated for the three kinds of particles, from the initial flocculation temperature, and was found to be comparable to the value determined directly.