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No. of bitstreams: 1 brock_rs_dr_bot.pdf: 138052465 bytes, checksum: f5b517e489dbadd6cf6b83fbef881ecd (MD5) Previous issue date: 2017-01-31 / As deformidades craniofaciais decorrentes de traumas, ressecções de tumores ou malformações congênitas são freqüentes na prática médica e o tratamento destas necessitam de cirurgia reparadora, com técnicas especializadas e profissionais qualificados para corrigir os defeitos e proporcionar melhor qualidade de vida, aprimorar a fala, respiração, mastigação e deglutição. Há diversas técnicas descritas para corrigir os defeitos ósseos, cada uma com vantagens e desvantages, escolhidas de acordo com o tipo de deformidade. Este estudo avaliou a formação óssea em um retalho tubular vascularizado, gáleo-periostal, enriquecido com o uso de pó de osso, plasma rico em plaquetas, células-tronco mesenquimais e ácido hialurônico, em coelhos, que tenha capacidade de substituir o enxerto ósseo nas reconstruções, principalmente nos defeitos faciais. No estudo, utilizou-se 98 coelhos divididos em doze grupos, submetidos à cirurgia para confecção do retalho em calota craniana. Foram realizados retalhos tubulares com o periósteo voltado para dentro e preenchidos com pó de osso, plasma rico em plaquetas (PRP), células-tronco mesenquimais (CTM) e ácido hialurônico. O Grupo 1 não foi manipulado. No Grupo 2 foi realizado o retalho tubular e mantido vazio. O Grupo 3 teve o retalho preenchido com pó de osso, no Grupo 4 o retalho foi mantido vazio. O Grupo 5 teve o retalho preenchido com PRP. No Grupo 6 o retalho foi preenchido com PRP e pó de osso. O Grupo 7 foi preenchido com CTM. O Grupo 8 teve o retalho preenchido com CTM e pó de osso. O Grupo 9 teve o retalho preenchido com CTM e PRP. No Grupo 10, o retalho tubular foi preenchido com PRP, CTM e pó de osso. O Grupo 11 foi mantido vazio e o Grupo 12 foi preenchido com ácido hialurônico. Os resultados foram avaliados através de métodos de imagem e avaliação histológica. Os resultados demonstraram que, no modelo experimental utilizado, os grupos com apenas periósteo, isto é, retalho tubular vazio, apresentaram formação óssea pequena e irregular. No grupo com PRP também houve a formação óssea irregular e imatura. Quando o PRP foi associado ao pó de osso houve uma formação mais regular e organizada. O grupo com célula-tronco mesenquimal também apresentou formação óssea, com características teciduais organizadas, próprias do tecido ósseo maduro. Quando associada ao pó de osso e ao PRP, as características histológicas apresentaram-se com tecido organizado, regular, maduro com células bem formadas e organizadas. O uso de materiais com fatores de crescimento celular ósseo melhoram a qualidade e organização do tecido neoformado. Quanto maior o número de fatores de enriquecimento usados, melhores foram os resultados quanto a qualidade tecidual neoformada. / Craniofacial deformities caused by traumas, tumor ressections or congenital malformation are frequent in medical practice, and their treatment with reconstructive surgeries are common, especially in plastic surgery, which aim to provide the patients with better quality of life and functional improvement of speach, breathing, chewing and swallowing. Many different techniques are described to correct bone defects. They have advantages and disadvantages, chosen according to the type of deformity. This study evaluated a vascularized galeal and periosteum flap filled with bone fragments, platelet rich plasma, mesenchymal stem cells and hyaluronic acid, using rabbits, which could possibily substitute the bone graft in reconstructive surgery, especially for facial defects. It was an experimental study, with 98 rabbits divided into twelve groups, submitted to a surgical procedure to construct a calvaria flap. A tubular flap with the periosteum inside was constructed and filled with bone fragments, platelet rich plasma (PRP), mesenchymal stem cells (MSC) and hyaluronic acid. Group 1 was not manipulated. In Group 2, the tubular flap was maintained empty. Group 3 had the flap filled with bone fragments, in Grupo 4 the flap was maintained empty. Group 5 had the flap filled with PRP. In Group 6 the flap was filled with PRP and bone fragments. The Group 7 was filled with MSC. Group 8 had the flap filled with MSC and bone fragments. The Group 9 had the flap filled with MSC and PRP. In Group 10, the tubular flap was filled with PRP, MSC and bone fragments.The Group 11 was maintained empty and Group 12 was filled with hyaluronic acid. The results were evaluated using image methods and histological analysis. The results demonstrated that, in the experimental model used, the groups with only periosteum, this is the empty tubular flap, presented small and irregular bone formation. In the group with PRP, it also had irregular and imature bone formation. When the PRP was associated to bone fragments it had a more regular and organized formation. The group with mesenchymal stem cell also presented bone formation, with organized tissue characteristics, proper of mature osseous tissue. When associated to bone fragments and PRP, the histological characteristics presented organized, regular, mature tissue with organized and well formed cells. The use of materials with osseous cellular growth factors improves the quality and organization of the neoformed tissue. The more enrichment factor used, the better the neoformed tissue quality result was.

The present thesis focuses on the selection of polymers and methods to fabricate stable and stimuli responsive multilayer self-assembly via layer-by-layer (LbL) approach. The polymers utilized in this study are biodegradable and biocompatible such as hyaluronic acid, chitosan and poly(vinyl alcohol) (PVA). The thesis is comprised of six chapters and a brief discussion on the contents of the individual chapters is given below. Chapter I reviews the LbL self-assembly approach in the context of drug delivery. The various interactions such as electrostatic, hydrogen bonding and covalent bonding involved in preparation of stable multilayer assemblies via LbL approach are discussed. Stimuli responsive behaviour of these multilayer assemblies can be tuned by choosing suitable depositing materials and method. Preparation of hollow microcapsules using LbL approach and its application in drug delivery has also been described in this chapter. Chapter II deals with the LbL assembly of a neutral polymer, poly(vinyl alcholol) (PVA). The negative charge on PVA backbone was induced by physical cross-linking with borax. The PVA-borate can undergo electrostatic interaction with positively charged chitosan in LbL process to form multilayer thin film. The thin film of PVA-borate complex/chitosan was found be responsive towards glucose concentration; disintegration of the multilayer assembly was observed at a high glucose concentration. This finding was rationalized on the basis of strong interaction of glucose with borate ions leading to dissociation of PVA-borate complex and subsequent collapse of the assembly. Thus, this multilayer self-assembly is potent for glucose triggered drug delivery. Chapter III reports the construction of a stable hydrogen bonded multilayer self-assembly based on complementary DNA base pairs (adenine and thymine) interaction. The natural polymer such as chitosan was modified with adenine whereas hyaluronic acid was modified with thymine. These two modified polymers were sequentially deposited on flat substrate and melamine formaldehyde (MF) particles; wherein strong interaction among the DNA base pairs led to the formation of stable assembly without utilizing any external cross-linking agent. The modified polymers are non-cytotoxic as proved from MTT assay. Further the multilayer assembly was used for pH responsive anticancer drug doxorubicin hydrochloride (DOX) release. In Chapter IV, glutaraldehyde mediated LbL self-assembly of single polymer multilayer thin films on flat and colloidal substrate by covalent bonding is described. A comparitive study between the native polymer (chitosan) and adenine modified polymer in the growth of thin film is performed. It is established from the study that the conformation of polymer and the availability of cross-linking points on the polymer play a crucial role in controlling the growth of these multilayer assemblies. Chapter V is divided into two parts (A and B). Part A describes a simple and unique protocol for fabrication of water dispersed chitosan nanoparticles (CH NPs). The method utilized in this work is based on the fast desolvation technique without using any additional stabilizer or any sophisticated instrumental setup. Furthermore, the CH NPs prepared from the mentioned protocol were proved to be cell-viable and are found to be responsive towards pH of the solution. In part B of this chapter, the LbL self-assembly of the responsive CH NPs is fabricated via electrostatic interaction with hyaluronic acid (HA). The growth of the multilayer thin film was found to be linear as function of number of bilayers. The morphology of thin film was characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The microscopic images reveal the uniform film morphology devoid of any phase separation of nanoparticles and polymers. Subsequently, the film was loaded with an anticancer therapeutic, doxorubicin hydrochloride (DOX). The release dynamics of encapsulated drug from the self-assembly are tunable and pH responsive. Chapter VI deals with the general and versatile method for the encapsulation of hydrophobic model drugs into polymeric multilayer assembly by using LbL approach. Electrical charge was induced on the surface of pyrene (uncharged organic substance) using an amphiphilic surfactant, sodium dodecyl sulfate (SDS) by micellar solubilization. The SDS micellar solution of pyrene was utilized to grow LbL multilayer thin film on a planar substrate and colloidal particles along with chitosan as a polycation. The LbL self-assembly of pyrene loaded SDS micelles/chitosan is additionally able to encapsulate hydrophobic or hydrophilic model therapeutics, thus providing an opportunity for dual-drug delivery. The desorption kinetics of the two model drugs from the thin film is found to follow a second order rate model.

En un intento de optimizar el sistema de fecundación in vitro en la especie porcina se estudió la influencia de distintas condiciones de maduración y de cocultivo de los gametos. Se evaluó la reducción del tiempo de coincubación de los gametos a 10 min observándose un claro efecto del ratio espermatozoides:ovocito. El estudio de las necesidades de los espermatozoides en términos de aditivos del medio de fecundación y tiempo de coincubación reveló variaciones entre verracos. La utilización de un tiempo de coincubación tan corto como 2 min fue suficiente para obtener unas tasas de penetración y monospermia similares a las alcanzadas por los sistemas de FIV tradicionales. El sistema de FIV en pajuela con 10 min de coincubación aumentó la penetración monoespérmica y mejoró la calidad de los blastocistos. La adición de 5 nM de 9- cis ácido retinoico al medio de maduración aumentó significativamente la formación de blastocistos. / The present study was conducted in an attempt to optimize porcine in vitro fertilization system. For this purpose, the influence of maturation and gamete coculture conditions were studied. The coincubation time may be reduced to 10 min to increase the efficiency of fertilization depending on the sperm:oocytes ratio. The needs of boar spermatozoa for IVF, in terms of additives to IVF medium and coincubation times vary among boars. The use of coincubation time as brief as 2 min is long enough to obtain good fertilization rates similar to those achieved from current long term exposure times in IVF. A straw IVF system in combination with a 10 min coincubation increased monospermic penetration and the quality of blastocysts compared with the microdrop-IVF system. The addition of 5 nM of 9- cis retinoic acid in the IVM medium increased blastocyst formation rate, suggesting that RA may play an important role during IVM.

Establishing highly sophisticated polymer films for delivery systems in a biological environment and bioanalytical tasks, the formation, thickness, swelling behavior, and (physiological) stability of highly biocompatible polyelectrolyte multilayers (PEMs) are described. These PEMs are composed of the very weak polycation maltose-modified hyperbranched poly(ethyleneimine) (PEI-Mal), strongly polyanion heparin sodium salt (HE − Na +) or weakly charged polyanion hyaluronic acid sodium salt (HA-Na+) deposited on Si wafer substrates. Two different glyco architectures for PEI-Mal are used, characterized by two different degrees of maltose decoration on a PEI scaffold. Using three pH-dependent deposition approaches for optimizing the (physiological) PEM stability and swelling, PEMs are characterized by (in situ) ellipsometry, atomic force microscopy (AFM), and (in situ) attenuated total reflection-Fouriertransform infrared (ATR-FTIR). Thus, PEMs reveal significantly different thicknesses, growth mechanisms (linear versus exponential), and swelling behavior in dependence of both the polycation architectures and the deposition protocol. These PEMs will allow the study of their complexation and release properties as preswollen PEMs against anionic drug molecules, adenosine triphosphate sodium salt (ATP), especially under physiological conditions for future drug delivery coatings.

O presente estudo destinou-se a avaliar se os resultados clínicos iniciais da viscossuplementação poderiam ser melhorados com a adição de corticosteróide. As injeções intra-articulares são usadas há muitos anos no tratamento da osteoartrite dos joelhos, principalmente com suspensões cristalinas de corticosteróides. A viscossuplementação é uma intervenção relativamente nova, atualmente recomendada no tratamento da osteoartrite. Trata-se da injeção de ácido hialurônico exógeno em articulações diartrodiais, visando, além de restaurar as propriedades reológicas do líquido sinovial, efeitos modificadores da doença osteoartrite. Revisões sistemáticas mostram que a melhora clínica ocorre em duas a cinco semanas após a viscossuplementação. Comparando-se a viscossuplementação com a injeção intraarticular com corticosteróides, dados recentes sugerem maior eficiência no alívio da dor nas quatro primeiras semanas após a infiltração com corticosteróides, similaridade dos procedimentos ao redor da quarta semana e melhores resultados com a viscossuplementação após a oitava semana. Este inicio de ação mais tardio, associado a relatos de sinovite reacional após a viscossuplementação podem desencorajar médicos e pacientes ao uso desta modalidade de tratamento. No presente estudo foram avaliados 104 pacientes em tratamento para osteoartrite do joelho no grupo de doenças osteometabólicas do Instituto de Ortopedia do Hospital das Clínicas da FMUSP. Os pacientes foram randomizados em dois grupos. Um dos grupos foi denominado VS e recebeu uma única injeção intra-articular de 6ml de Hylan GF-20 (Synvisc One®-Genzyme) no joelho estudado. O segundo grupo foi denominado VS+T e recebeu uma injeção intra-articular de 6ml de Hylan GF-20 (Synvisc One®-Genzyme) mais 1ml (20mg) de Hexacetonido de Triancinolona (Triancil®-Apsen). Foram aplicados a escala visual analógica de dor (EVA) e os questionários de WOMAC e Lequesne uma semana antes da injeção e após uma, quatro, 12 e 24 semanas. Os dois grupos com 52 pacientes cada eram homogêneos. Na primeira semana, o WOMAC e a EVA apresentaram melhores resultados no Grupo VS+T (p < 0,01) em relação ao Grupo VS. Na quarta semana não houve diferença entre os grupos. Ambos apresentaram resultados similares nas semanas 12 e 24. Concluiu-se que a adição de hexacetonido de triancinolona melhorou os resultados clínicos da viscossuplementação no curto prazo, sem interferir nos resultados a longo prazo ou na incidência de efeitos adversos / The present study aims to assess if the initial results of viscosupplementation can be improved by the addition of corticosteroid. Intraarticular injections have been used for many years to treat arthritis and other painful articular disorders, mainly using long-lasting crystalline corticosteroid suspensions. Viscosupplementation is a relatively new intervention that is now widely used and recommended for the treatment of knee osteoarthritis. It is comprised of the injection of exogenous hyaluronic acid in diarthrodial joints, in order to restore the rheological properties of synovial fluid and also to promote osteoarthritis disease-modifying effects. Several placebo-controlled studies reported that clinical improvement began only within two to five weeks after viscosupplementation. When comparing viscosupplementation versus intraarticular injection of corticosteroid, recent data suggest that from baseline to week four, intraarticular steroid were more effective for pain relief. By the fourth week, however, both provided similar relief, but beyond the eighth week, hyaluronic acid provided greater pain reduction. The mechanism of action of hyaluronic acid, with delayed onset of pain/functional improvement, combined with reports of reactional sinovitis may discourage physicians and patients regarding this treatment modality. The present study evaluated 104 patients receiving usual care for knee osteoarthritis at the University of São Paulo Medical Center. Patients were randomized to receive either a single intra-articular injection of 6ml of Hylan GF-20 (Synvisc One®-Genzyme) (Group VS) or a single intra-articular injection of 6ml of Hylan GF-20 (Synvisc One®-Genzyme) plus 1ml (20mg) of Triamcinolone Hexacetonide (Triancil®-Apsen) (Group VS+T). VAS, WOMAC and Lequesne questionnaires were applied one week prior the injection, and after one, four, 12 and 24 weeks. The two groups with 52 patients each were homogeneous. At week one, WOMAC and VAS showed better results for Group VS+T compared to Group VS (p < 0,05). At week four the scores did not show statistically significant differences. The groups showed similar results at weeks 12 and 24. In conclusion, the addition of triamcinolone improved first-week symptom and functional scores of viscosupplementation, but not beyond. It did not seem to alter the likelihood of adverse effects

Beim Tissue Engineering ist die Vaskularisierung von größeren Zell-Matrix-Konstrukten nach Implantation bis heute ein großes Problem. Durch das initiale Fehlen eines mikrovaskulären Netzwerkes kommt es zu einem raschen Zellsterben im Scaffold. Aufgrund dessen war das Ziel dieser Arbeit, im Sinne des in situ-Tissue Engineering ein Scaffold auf Basis von mineralisiertem Kollagen zu entwickeln, welches mit dem angiogenen Wachstumsfaktor VEGF funktionalisiert wird, um den Prozess der Vaskularisierung – die Einsprossung von Blutgefäßen – zu fördern und gleichzeitig durch Chemoattraktion in vivo Zellen aus dem umliegenden Knochengewebe in das Innere des Scaffolds migrieren zu lassen, so dass eine beschleunigte Defektheilung erzielt wird. Poröse Scaffolds aus mineralisiertem Kollagen wurden durch zwei unterschiedliche Strategien funktionalisiert und durch in vitro-Testungen charakterisiert. Die erste Strategie umfasste die Heparin-Modifizierung der gesamten Scaffolds, während die zweite Strategie die Injizierung eines zentralen VEGF-haltiges Depots in das Scaffoldinnere darstellte. Neben der Charakterisierung der Scaffolds wurde die Freisetzungskinetik des Modellwachstumsfaktors VEGF aus den modifizierten Scaffolds untersucht und die biologische Aktivität des freigesetzten Faktors auf Endothelzellen getestet. Zusätzlich wurde bei der 2. Strategie, der Injizierung eines Wirkstoffdepots, die Ausbildung eines Wirkstoffgradienten und die zielgerichtete Migration von Endothelzellen in Richtung des Wirkstoffdepots analysiert.

Establishing highly sophisticated polymer films for delivery systems in a biological environment and bioanalytical tasks, the formation, thickness, swelling behavior, and (physiological) stability of highly biocompatible polyelectrolyte multilayers (PEMs) are described. These PEMs are composed of the very weak polycation maltose-modified hyperbranched poly(ethyleneimine) (PEI-Mal), strongly polyanion heparin sodium salt (HE − Na +) or weakly charged polyanion hyaluronic acid sodium salt (HA-Na+) deposited on Si wafer substrates. Two different glyco architectures for PEI-Mal are used, characterized by two different degrees of maltose decoration on a PEI scaffold. Using three pH-dependent deposition approaches for optimizing the (physiological) PEM stability and swelling, PEMs are characterized by (in situ) ellipsometry, atomic force microscopy (AFM), and (in situ) attenuated total reflection-Fouriertransform infrared (ATR-FTIR). Thus, PEMs reveal significantly different thicknesses, growth mechanisms (linear versus exponential), and swelling behavior in dependence of both the polycation architectures and the deposition protocol. These PEMs will allow the study of their complexation and release properties as preswollen PEMs against anionic drug molecules, adenosine triphosphate sodium salt (ATP), especially under physiological conditions for future drug delivery coatings.

Beim Tissue Engineering ist die Vaskularisierung von größeren Zell-Matrix-Konstrukten nach Implantation bis heute ein großes Problem. Durch das initiale Fehlen eines mikrovaskulären Netzwerkes kommt es zu einem raschen Zellsterben im Scaffold. Aufgrund dessen war das Ziel dieser Arbeit, im Sinne des in situ-Tissue Engineering ein Scaffold auf Basis von mineralisiertem Kollagen zu entwickeln, welches mit dem angiogenen Wachstumsfaktor VEGF funktionalisiert wird, um den Prozess der Vaskularisierung – die Einsprossung von Blutgefäßen – zu fördern und gleichzeitig durch Chemoattraktion in vivo Zellen aus dem umliegenden Knochengewebe in das Innere des Scaffolds migrieren zu lassen, so dass eine beschleunigte Defektheilung erzielt wird. Poröse Scaffolds aus mineralisiertem Kollagen wurden durch zwei unterschiedliche Strategien funktionalisiert und durch in vitro-Testungen charakterisiert. Die erste Strategie umfasste die Heparin-Modifizierung der gesamten Scaffolds, während die zweite Strategie die Injizierung eines zentralen VEGF-haltiges Depots in das Scaffoldinnere darstellte. Neben der Charakterisierung der Scaffolds wurde die Freisetzungskinetik des Modellwachstumsfaktors VEGF aus den modifizierten Scaffolds untersucht und die biologische Aktivität des freigesetzten Faktors auf Endothelzellen getestet. Zusätzlich wurde bei der 2. Strategie, der Injizierung eines Wirkstoffdepots, die Ausbildung eines Wirkstoffgradienten und die zielgerichtete Migration von Endothelzellen in Richtung des Wirkstoffdepots analysiert.

Future changes in the incidence and prevalence of OA are difficult to predict. As incidence and prevalence rise with increasing age, extending life expectancy will result in greater numbers with OA. Actually, usual therapeutic approaches are really restricted because of important side effects with long-term use. Therefore, there is a need to develop improved formulations which are well tolerated, biocompatible and biodegradable. Ideally, these new treatments should be able to deliver locally sufficient amount of anti-inflammatory or analgesic drugs into the site of arthritic inflammation while stabilizing or better restoring the mechanical integrity of the joint. In this way, the objective of this project is to develop slow-release gels that are sterile, injectable, characterized by viscoelastic properties and capable to sustain the in situ release of both hydrophilic and lipophilic drugs. The intraarticular delivery combined to sustained-release property should be interesting to reduce the number of injection required while prolonging the local drug activity over weeks. For that purpose, glycerol monooleate (GMO), also called “monolein” was selected for its capacity to form highly viscous crystalline phase structures upon contact with an aqueous fluid (e.g. synovial fluid). <p>In the first step of this work, it was decided to develop and characterize hydro-lipidic gels based on the use of monolein and hyaluronic acid in order to provide in vitro sustained release of hydrophilic drugs such as clonidine and lipophilic drugs such as betamethasone. Initially, a compatibility study was performed on the main ingredients selected in order to check that there were not physico-chemical incompatibilities, which could be deleterious regarding to their stability in formulation. Then, the development of hydro-lipidic gels was initiated by considering on the first hand the solubility of each ingredient and on the other hand the syringeability, the rheological properties and the in vitro dissolution profiles obtained for the developed formulations. The objective of this preformulation program was to identify potential candidates that presented suitable syringeability while being able to sustain the release of drugs over weeks and being characterized by interesting viscoelastic properties for the long-term management of osteoarthritis. Moreover, several methods of quantification and characterization were developed in order to allow the physico-chemical properties (rheology, syringeability, water uptake, stability and dissolution profiles) of the developed formulations to be studied.<p>Results of the compatibility study showed that the concomitant use of monolein, hyaluronic acid and clonidine/betamethasone is not contraindicated. Next, the preformulation program allowed many injectable drug delivery systems to be prepared. However, the carrier that best meets our needs was composed of 10,0 % (wt/wt) absolute ethanol ;15,0 % propylene glycol (wt/wt) ;15,0 % (wt/wt) water ;55,0 % (wt/wt) de monolein ;5,0 % (wt/wt) purified soybean oil ;0,03 % (wt/wt) α-tocophérol and 7,5 mg/g sodium hyaluronate (1.9 MDa). This carrier assured suitable syringeability and rheological properties. Indeed, it presented marked pseudoplastic flow behavior that allowed relatively fast injection through a narrow needle, followed by an increase in viscosity upon contact with aqueous fluids to obtain an in vitro sustained release of hydrophilic and lipophilic drugs over a few weeks. As a consequence, it was assumed that this carrier should be able to jellify in situ upon contact with physiological fluid such as synovial fluid. Then, according to EMA recommendations, a fast and easy manufacturing process that could be applied in a cleanroom at industrial scale was validated in our Laboratory. Finally, according to these promising results obtained in vitro, a stability study was performed on the carrier alone and containing clonidine or betamethasone according to ICH recommendations described for products intended for storage in a refrigerator. In that purpose, several parameters such as the quantification of drugs, the pH, the molecular weight of hyaluronic acid, the dissolution profiles of drugs and the rheological properties of the formulations were recorded depending on time and conditions of storage. This stability study showed clearly the importance to adjust the pH value of the formulation. Indeed, it was demonstrated that a pH value of 6.5, adjusted with diluted NaOH, allowed the stability of the formulation to be significantly improved. During this first step of this project, our Laboratory initiated two new collaborations. On the first hand, collaboration with the Laboratory of Professor Siepmann (University of Lille 2 – Faculty of Pharmacy) was started for their expertise on mathematical modeling. On the other hand, collaboration with the Laboratory of Professor Jerôme (ULg – Faculty of sciences) was started for their expertise on macromolecular chemistry and more particularly on rheological properties.<p>In the second step of this work, it was decided to evaluate in vitro the safety and the efficiency of the developed carrier and formulations containing clonidine or betamethasone. In this way, it was suggested to test selected drugs and potential candidates formulations on equine polymorphonuclear leukocytes (PMN) by measuring the production of reactive oxygen species (ROS) by PMNs stimulated or not with phorbol 12-myristate 13-acetate (PMA). For that purpose, our Laboratory initiated a new collaboration with the Laboratory of Professor Serteyn (ULg – Faculty of veterinary) for their expertise on equine PMNs and quantification of (ROS) produced in particular in inflammatory diseases.<p>This in vitro study has shown that no pro-inflammatory effect appeared by incubating carrier with unstimulated PMNs in comparison with the control assay. However, the production of ROS was quickly and considerably decreased when stimulated cells were placed in contact with carrier regardless on the incorporation of clonidine or betamethasone. This observation demonstrated that developed carrier provided a strong antioxidant effect, certainly by trapping the ROS produced. These results were very promising because that antioxidant effect of carrier could inhibit oxidative damages and might consequently potentiate the prevention of inflammatory conditions. Concerning the clonidine and betamethasone, only the last one provided significant inhibition of the ROS activity.<p>Finally, by considering the very promising results obtained with the in vitro study on PMNs, an in vivo study on rabbits, which seemed to be the most appropriate small animal model for this kind of intraarticular formulations, was performed to evaluate the toxicity and the efficiency of the developed carrier and formulation containing betamethasone. Therefore, our Laboratory started collaboration with the unit of research in osteo-articular pathologies (UROC) of Pr. Henrotin (ULg) for their expertise in animal models, in particular rabbits with osteoarticular pathologies such as osteoarthritis. For this purpose, this in vivo study was outsourced by TNO (Delft, Holland) and was designed as follow: (i) 0.9 % saline buffered (n=8); (ii) carrier (n=8); (iii) formulation containing betamethasone (n=8); (iv) Durolane® (n=8) a marketed product of HA. Surprisingly, it seemed that the control group (saline buffered) presented macroscopical and histological scores that were globally low according to literature. As a consequence, it was difficult to conclude about the efficiency of the developed treatments by considering only this pilot study. However, it is important to note that it seemed that the expected viscoelastic protection of the carrier to prevent the degradation of articular cartilage was not optimal regardless on the incorporation of betamethasone. Nevertheless, the histological analyses of synovial membranes from each treated groups demonstrated that there was no pro-inflammatory reaction. This meant that all formulations tested were well tolerated despite of the apparition of lumps (in 37.5 % of treated rabbits) that are probably due to both the high volume injected (900 µL) and an excessive and unexpected in situ water uptake of developed formulations based on GMO. However, this lack of rejection of the developed carrier could be very important since it allowed new perspectives to be considered. For example, other articular disorders could be targeted by incorporating drugs, for which in situ sustained release or mechanical protection could be beneficial. <p>Our laboratory is member of a collaborative project "JOINT-AIC" from BioWin and is supported by a grant from the Walloon Region. The development of analytical methods, the evaluation of physico-chemical properties and finally the preparation of sterile batches of formulations based on GMO intended for in vitro and in vivo studies were performed in the Laboratory of Galenic and Biopharmacy of the Faculty of Pharmacy of ULB./L’arthrose est une pathologie dont la prévalence et le coût ne font qu’augmenter dans notre société vieillissante. Les moyens thérapeutiques actuels étant fort limités suite à de sérieux effets secondaires à long terme, il existe réellement un besoin médical important de développer de nouveaux traitements locaux qui soient bien tolérés, biocompatibles et biodégradables. Idéalement, ceux-ci devraient être actifs au niveau du processus inflammatoire ou de la douleur tout en étant capable de stabiliser, voire de restaurer, l’intégrité mécanique de l’articulation. <p>Dans cette optique, l’objectif de ce projet a été de développer des systèmes hydrolipidiques stériles, injectables et viscoélastiques qui soient capables de prolonger in situ la libération de principes actifs hydrophiles et lipophiles. Cette caractéristique devait permettre de réduire le nombre d’injections nécessaires dans le cadre du traitement symptomatique de l’arthrose et de maintenir l’effet des composés sur un minimum de quatre à six semaines. Cette étude entre dans le cadre du projet JOINT-AIC entièrement financé par le programme BioWin de la Région Wallonne. Le développement, la validation des méthodes analytiques, l’évaluation des propriétés physico-chimiques ainsi que la préparation stérile des lots de formulation destinés aux tests in vitro et in vivo ont été réalisés au sein du Laboratoire de Galénique et Biopharmacie de la Faculté de Pharmacie de l’ULB. <p>Au cours de ce projet, il a donc fallu dans un premier temps développer et caractériser des formulations hydrolipidiques à base de monoléine et d’acide hyaluronique permettant une libération in vitro prolongée de principes actifs tels que la clonidine (hydrophile) et le dipropionate de bétaméthasone (lipophile). Une étude de compatibilité a ainsi été préalablement réalisée afin de s’assurer qu’aucun des constituants principaux de la formulation ne présentaient d’incompatibilité physico-chimique qui pourrait être délétère vis-à-vis de leur stabilité en formulation. Ensuite, le développement de préparations hydro-lipidiques a été initié en tenant compte, d’une part de la solubilité des différents composants et, d’autre part de l’injectabilité, des propriétés rhéologiques et des profils de libération de la clonidine obtenus à partir des gels développés. Cette étude visait à obtenir une composition de référence qui soit à la fois injectable et capable de libérer un principe actif hydrophile sur plusieurs jours, voire plusieurs semaines, tout en possédant des propriétés rhéologiques intéressantes dans le cadre d’une viscosupplémentation articulaire. Enfin, un protocole de fabrication en milieu aseptique a été développé et plusieurs méthodes pour étudier les propriétés physico-chimiques des gels développés telles que la rhéologie, l’injectabilité, l’indice de gonflement, la stabilité et les profils de libérations ont été mises en place. <p>Les résultats ont montré qu’aucune incompatibilité ne semblait exister entre les trois composés majeurs de notre préparation, la monoléine, l’acide hyaluronique et la clonidine. Le développement des formulations nous a ensuite permis d’obtenir de nouveaux systèmes hydrolipidiques stériles et injectables à délivrance prolongée. Le véhicule qui remplissait au mieux nos objectifs était composé de 10,0% (m/m) d’éthanol ;de 15,0% de propylène glycol (m/m) ;de 15,0% (m/m) d’eau ;de 55,0% (m/m) de monoléine ;5,0% (m/m) d’huile de soja purifiée ;0,03% (m/m) d’α-tocophérol, de 7,5 mg/g d’HA et son pH était ajusté à 6,5 avec du NaOH 1N. Ce véhicule a montré un intérêt réel dans le cadre du développement de préparations biodégradables et biocompatibles pour le traitement de pathologies articulaires.En effet, cette composition présentait un écoulement de type pseudoplastique et des propriétés rhéologiques qui lui procuraient une bonne injectabilité. De plus, cette formulation a démontré in vitro une excellente capacité à gélifier au contact de fluides aqueux et à ralentir efficacement sur plusieurs semaines la libération des différents principes actifs incorporés (clonidine et dipropionate de bétaméthasone). Nous pouvions, dès lors, envisager que celle-ci serait capable de gélifier in situ au contact d’un fluide physiologique tel que le liquide synovial. Ensuite, suivant les recommandations de l’EMA, nous avons décidé d’utiliser l’association d’une filtration stérilisante et d’une préparation en milieu aseptique pour obtenir des formulations qui répondaient aux exigences en matière de préparation parentérale. C’est ainsi qu’un protocole de fabrication stérile de nos gels a été développé par nos soins en vue d’une éventuelle mise à l’échelle industrielle. Enfin, une étude de stabilité sur une année, suivant les normes ICH décrites pour des formulations destinées à être conservées au frigo, a été réalisée sur différents véhicules développés et contenant soit la clonidine, soit le dipropionate de bétaméthasone. Dans cette optique, plusieurs paramètres, tels que le dosage en principe actif, l’évolution du pH et du poids moléculaire de HA, le profil de libération ainsi que la rhéologie des formulations ont été évalués au cours du temps aux différentes conditions de conservation testées. Cette étude a permis de démontrer toute l’importance d’ajuster le pH de la préparation pour prévenir l’hydrolyse de l’HA, et cela indépendamment de l’incorporation de principe actif. Ainsi, il a pu être montré que l’ajustement du pH du véhicule à 6,5 à partir de NaOH dilué permettait d’améliorer considérablement la stabilité de la formulation puisqu’aucune modification significative de ses différents paramètres physico-chimiques et teneurs n’a été observée après un an de conservation à 5 et à 25 °C (60% HR) mais également après six mois à 30 °C (65% HR). Au cours de cette première partie, deux collaborations ont été initiées, l’une avec le Laboratoire du Prof. Siepmann de l’Université de Lille 2 et l’autre avec le Prof. Jerôme de l’Université de Liège. Avec l’aide du Prof. Siepmann, il a été possible de mettre au point un modèle mathématique pour caractériser les profils de libération des principes actifs à partir des différents véhicules développés. Le Prof. Jerôme a, quant à elle, mis à notre disposition un rhéomètre qui a permis d’approfondir nos connaissances sur les propriétés rhéologiques et viscoélastiques des formulations.<p>Ensuite, la seconde partie de notre travail a consisté à évaluer la tolérance, ainsi que l’efficacité des principes actifs sélectionnés et des formulations développées, à travers un modèle in vitro de cellules de l’inflammation (neutrophiles équins). Cette étude avait pour objectif d’évaluer deux aspects importants de la formulation :d’une part vérifier l’absence de réaction pro-inflammatoire qui pourrait être in vivo destructrice vis-à-vis du véhicule ainsi que des tissus environnants, et d’autre part vérifier l’effet anti-inflammatoire propre à la clonidine et au dipropionate de bétaméthasone seuls et en formulation. Cette étude a été réalisée avec la collaboration du Laboratoire du Prof. Serteyn de l’Université de Liège.Cette étude in vitro a démontré que les cellules restaient viables au moins pendant quatre heures lorsqu’elles étaient exposées à la matrice épurée de ses solvants. Ensuite, de manière surprenante, il a même pu être démontré que le véhicule permettait à la fois de prévenir et de réduire significativement la production des espèces réactives de l’oxygène (ROS) par les neutrophiles équins lorsque ceux-ci étaient stimulés au phorbol 12-myristate 13-acetate (PMA). Cette propriété peut être d’un grand intérêt dans le cadre de la prise en charge de l’arthrose car cette activité antioxydante pourrait permettre d’inhiber les dommages oxydatifs générés par les ROS et ainsi prévenir les dommages liés au développement du processus inflammatoire et qui peut, à long terme, s’avérer délétère pour les tissus environnants tels que le cartilage. Cette propriété du véhicule semble trouver son origine dans la monoléine qui, de par sa composition en alpha-tocophérol (200 ppm), présente également une activité antioxydante vis-à-vis des ROS. Toutefois, une action synergique liée à l’HA, à l’huile de soja ou à l’alpha-tocophérol incorporés aux formulations, n’est pas à exclure. Enfin, parmi les deux principes actifs sélectionnés, seul le dipropionate de bétaméthasone a montré une inhibition significative de la production des ROS.<p>Enfin, en tenant compte des résultats obtenus sur cellules, une étude in vivo pilote a été réalisée sur base d’un modèle de lapins. Cette étude visait à vérifier la tolérance ainsi que l’efficacité en prophylaxie de l’arthrose du véhicule développé ainsi que de la formulation contenant le dipropionate de bétaméthasone. Dans ce but, quatre groupes d’animaux (n=8) ont été constitués pour chacun des traitements testés :(i) groupe témoin :0,9 % tampon salin pH 7,4 ;(ii) véhicule à base de GMO développé; (iii) véhicule contenant du dipropionate de bétaméthasone ;(iv) groupe référence :Durolane®. Cette étude a été réalisée avec l’aide du Laboratoire du Prof. Henrotin de l’Université de Liège. L’hébergement des animaux ainsi que les actes chirurgicaux ont, quant à eux, été sous-traités par TNO (Delft, Pays-Bas).<p>De manière étonnante, il s’est avéré que le groupe contrôle présentait des scores macroscopique et histologique globalement peu élevés par rapport à ce qui est rapporté dans la littérature. Compte tenu de cette observation, il est difficile de se prononcer, sur base uniquement de cette étude, sur l’efficacité des différents traitements testés. Toutefois, il faut reconnaître que l’effet protecteur attendu pour le véhicule vis-à-vis de la dégradation du cartilage ne semble pas optimal et cela indépendamment de l’incorporation de dipropionate de bétaméthasone. Par ailleurs, l’étude des membranes synoviales a permis de démontrer qu’il n’y avait aucune différence significative en termes d’inflammation et de structure entre le groupe contrôle et les différents groupes traités. Ce qui signifie qu’aucun rejet n’a été observé vis-à-vis des formulations et que celles-ci ont, par conséquent, été bien tolérées malgré la formation de masses liées probablement au volume important injecté (900 µL) et au gonflement in situ du produit chez 37,5 % des lapins. Cette observation est importante puisqu’elle permet d’envisager de nouvelles perspectives telles que l’incorporation d’autres principes actifs pouvant éventuellement viser d’autres pathologies articulaires et pour lesquels une libération prolongée ou une protection mécanique du principe actif in situ serait bénéfique. <p><p><p><p><p><p> / Doctorat en Sciences biomédicales et pharmaceutiques / info:eu-repo/semantics/nonPublished