• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 19
  • 7
  • 1
  • Tagged with
  • 29
  • 17
  • 5
  • 5
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Efeitos da corticoterapia sobre a hemodinâmica fetoplacentária e fetal em casos de diástole zero nas artérias umbilicais / Effects of corticosteroid therapy on fetal-placental and fetal hemodynamics in cases of absent end-diastolic flow in the umbilical arteries

Alexandre Massao Nozaki 29 August 2007 (has links)
Objetivo: Avaliar o comportamento da dopplervelocimetria de artérias umbilicais, artéria cerebral média e ducto venoso após utilização de corticoterapia antenatal para maturação pulmonar fetal em casos de diástole zero à dopplervelocimetria das artérias umbilicais. Métodos: Analisaram-se de forma prospectiva 22 gestações com diagnóstico de diástole zero à dopplervelocimetria das artérias umbilicais, no período de maio de 2004 a fevereiro de 2006. Foram incluídas gestações únicas com fetos sem malformações, idade gestacional de 26 a 34 semanas e com indicação para utilização de corticóide antenatal para maturação pulmonar fetal (betametasona - 12mg/dia por dois dias) e posterior resolução da gestação. Para uso do referido medicamento foi necessária a presença de ao menos uma das seguintes condições: valores do ducto venoso (índice de pulsatilidade para veias - IPV) de 1 a 1,5 ou oligoâmnio (índice de líquido amniótico inferior a 5,0 cm). Foram analisados os índices de pulsatilidade das artérias umbilicais, artéria cerebral média e ducto venoso antes da primeira dose do corticóide (D0), 24 horas (D1) e 48 horas (D2) após a primeira dose de betametasona. Para análise estatística foi utilizado o teste de análise de variância com medidas repetidas e adotado nível de significância de 5%. Resultados: Em todos os casos realizaram-se cesarianas em intervalo de 24 a 36 horas após a segunda dose de corticóide. A média de idade gestacional no parto foi de 29,09 (±1,94) semanas e de peso no nascimento de 800,90 (±246,49) gramas. Em 19 (86,3%) casos verificou-se diminuição dos valores do índice de pulsatilidade no sonograma das artérias umbilicais, sendo que em 15 (68,1%) houve retorno do fluxo diastólico final. A média dos índices de pulsatilidade das artérias umbilicais no D0 foi 2,91 (±0,59); no D1: 2,16 (±0,63) e no D2: 2,54 (±0,74), com diferença significativa do D0 para D1 (p<0,001). Não houve modificações significativas na dopplervelocimetria da artéria cerebral média nas 48 horas subseqüentes ao uso de corticóide (p=0,686). Na dopplervelocimetria do ducto venoso notou-se diminuição dos valores do índice de pulsatilidade para veias, com as seguintes médias: D0: 1,02 (±0,26), D1: 0,71 (±0,16), D2: 0,69 (±0,13). Nota-se diminuição significativa dos valores de IPV do ducto venoso à comparação do D0 com D1 (p<0,001) e do D0 com D2 (p<0,001). Conclusão: Houve diminuição significativa dos índices de pulsatilidade da artéria umbilical e de pulsatilidade para veias do ducto venoso nas primeiras 24 horas após o uso de betametasona. Os índices de pulsatilidade da artéria cerebral média não apresentaram modificações significativas nas 48 horas subseqüentes ao uso de corticóide Verificou-se, também, ausência de modificações significativas no índice de pulsatilidade para veias do ducto venoso quando comparados os valores referentes ao D1 com aqueles encontrados no D2. / Objective: To evaluate the Doppler velocimetry findings in the umbilical arteries, middle cerebral artery and ductus venosus after prenatal corticosteroid therapy for fetal lung maturation in cases of absent end-diastolic umbilical artery Doppler flow. Methods: Twenty-two pregnancies with a diagnosis of absent end-diastolic umbilical artery Doppler flow were analyzed prospectively between May 2004 and February 2006. Included were single pregnancies with a gestational age of 26 to 34 weeks, whose fetuses showed no malformations and which had an indication for prenatal corticosteroid therapy for fetal lung maturation (12 mg/day betamethasone for 2 days) and subsequent pregnancy resolution. The use of the drug was necessary when at least one of the following conditions was present: ductus venosus flow velocity (pulsatility index for veins) of 1 to 1.5 or oligohydramnios (amniotic fluid index less than 5.0 cm). The pulsatility index of the umbilical arteries, middle cerebral artery and ductus venosus was determined before (D0) and 24 h (D1) and 48 h (D2) after the first betamethasone dose. The results were analyzed statistically by repeated measures analysis of variance, with the level of significance set at 5%. Results: A cesarian section was performed at an interval of 24 to 36 h after the second corticosteroid dose in all cases. The mean gestational age at delivery was 29.09 weeks (±1.94) and the mean birthweight was 800.90 g (±246.49). A decrease in the umbilical artery pulsatility index was observed in 19 (86.3%) cases, with a return of end-diastolic flow in 15 (68.1%). The mean umbilical artery pulsatility index was 2.91 (±0.59) at D0, 2.16 (±0.63) at D1, and 2.54 (±0.74) at D2, with a significant difference between D0 and D1 (p<0.001). No significant changes in the Doppler velocimetry findings of the middle cerebral artery was observed over the 48 h after corticosteroid administration (p=0.686). Ductus venosus Doppler velocimetry showed a decrease in the vein pulsatility index (D0: 1.02 (±0.26), D1: 0.71 (±0.16), D2: 0.69 (±0.13)) (p<0.001). There was a significant decrease in the vein pulsatility index of the ductus venosus between D0 and D1 (p<0.001) and between D0 and D2 (p<0.001). Conclusion: A significant decrease in the umbilical artery pulsatility index and in the vein pulsatility index of the ductus venosus was observed within the first 24 h after betamethasone administration. No significant changes in the Doppler velocimetry findings of the middle cerebral artery was observed over the 48 h after corticosteroid administration In addition, the ductus venosus pulsatility index values remained unchanged when comparing D1 and D2.
22

Caracterização, análise físico-química e estabilidade térmica do complexo de inclusão ciclodextrina-17-valerato de betametasona / Physicochemical characterization and thermal stability evaluation of betamethasone 17-valerate cyclodextrincomplex

Bruno Augusto Leite Evangelista 11 November 2010 (has links)
A preparação de formulações contendo o princípio ativo 17-valerato de betametasona (VB) é amplamente difundida entre as indústrias farmacêuticas, por se tratar de fármaco antiinflamatório de escolha, no tratamento de condições em que a terapia com corticoesteróides é indicada. Muito empregado no tratamento tópico de condições alérgicas e inflamatórias dos olhos, orelhas e nariz, inalação para a profilaxia da asma e também em veterinária. Isto devido ao seu alto poder antiinflamatório, quando comparado a outros corticoesteróides, e sua falta virtual de propriedades mineralocorticóides, causando baixa retenção de sódio e, subsequentemente, de água. Conforme descrita na Farmacopéia Americana USP 32 NF 27, o princípio ativo 17-valerato de betametasona hidrolisa-se em seu isômero 21-valerato de betametasona, seu principal produto de degradação, que possui baixo poder antiinflamatório. Adicionalmente, a norma brasileira em vigência para estudos de estabilidade de medicamentos, RE n°1, de 29 de Julho de 2005, propõe condições estressantes para estudo de estabilidade de longa duração (30°C/75%UR), o que acelera a reação de hidrólise (degradação) do princípio ativo. Conhecidamente, estudos prévios mostram que formulações tópicas contendo o VB (loção, creme, solução e pomada) apresentam uma estabilidade curta. Assim, uma forma de estabilizar o VB é a complexação (inclusão), com compostos de ciclodextrina (CD). O objetivo deste projeto foi estabelecer procedimentos para a obtenção, caracterização físico-química e avaliação de estabilidade térmica do complexo sólido supracitado. Para atender este objetivo técnicas de análise térmica (calorimetria exploratória diferencial e termogravimetria), infravermelho médio com transformada de Fourier, ressonância magnética nuclear e cromatografia líquida de alta eficiência, fizeram-se necessárias. / Preparation of formulations containing the active ingredient betamethasone 17-valerate (VB) is widely defunded within pharmaceutical industry, once it concerns an anti-inflammatory drug and an option, in the treatment of conditions in which corticosteroids therapy is indicated. Often employed in topical treatment of eye, ear and nose allergic and inflammatory conditions, inhalation for asthma prophylaxes, and also in veterinary. This because its high anti-inflammatory activity, when compared to others corticosteroids, and its virtual lack of mineralocorticoids properties, causing a low sodium retention and, subsequently, of water. As described in the United States pharmacopeia USP 32 NF 27, the active ingredient betamethasone 17-valerate hydrolyses into its isomer betamethasone 21- valerate, its main degradation product, that has a low anti-inflammatory activity . Additionally, the Brazilian legislation for drug products stability study, RE n°1, July 29th 2005, introduce long therm stability study stressing conditions (30°C/75%RH), accelerating the reactive hydrolysis (degradation) for the active ingredient. Well known, previous studies show that topical formulations containing VB (lotion, cream, solution and ointment) presents a short stability. Complexation (inclusion) with cyclodextrin (CD) compounds shows a reasonable way to improve the VB stability. The project objective is to establish procedures for the obtainment, physicochemical characterization and solid complex (cited above) thermal stability evaluation. In order to achieve this objective thermal analysis techniques (differential scanning calorimetry and thermogravimetry), Fourier transformation middle infrared, nuclear magnetic resonance and high performance liquid chromatography, were needed.
23

Effect of progesterone, terbutaline and leptin on the function of alveolar type II cells

Sammohi, Shamili 01 September 2015 (has links)
No description available.
24

Ciclo único de betametasona para maturação pulmonar fetal em casos com diástole zero ou reversa: impacto em resultados pós-natais / Single course of antenatal betamethasone therapy for the acceleration of fetal lung maturation in absent or reversed end-diastolic velocity in the umbilical arteries: impact on postnatal outcomes

Pereira, Luciana Carla Longo e 12 September 2007 (has links)
Para investigar o impacto em resultados pós-natais do uso de ciclo único de betametasona para maturação pulmonar em gestações (únicas, sem malformações fetais ou neonatais) com diástole zero ou diástole reversa à dopplervelocimetria das artérias umbilicais, foi conduzido estudo de coorte histórico com 62 recém-nascidos entre 26 e 34 semanas. Desses, 31 tinham uso antenatal do corticóide (nascidos entre maio de 2004 e julho de 2006) e 31 controles sem o uso da droga (nascidos entre janeiro de 2000 a março de 2004), pareados individualmente segundo índice de pulsatilidade para veias do ducto venoso (até 1,0 ou entre 1,01 e 1,50), idade gestacional ao nascimento (variação máxima de seis dias) e peso ao nascimento (variação máxima de 10%). Avaliaram-se: índice de Apgar de primeiro e quinto minutos, internação em unidade de terapia intensiva, uso de suporte respiratório (intubação orotraqueal, pressão positiva contínua nas vias aéreas, suplemento de oxigênio), tempo de internação, sobrevida, ocorrência de óbito (e causa principal), além da ocorrência de complicações (doença das membranas hialinas, displasia broncopulmonar, hemorragia intracraniana, retinopatia da prematuridade, persistência de canal arterial, enterocolite necrosante, sepse precoce e tardia). Fez-se análise estatística para os pares de recém-nascidos dos dois grupos, baseada na razão de pares discordantes e utilizaram-se os testes: t de Student para amostras pareadas, qui-quadrado de McNemar, de simetria assintótica, de Wilcoxon, de log-rank. No caso dos desfechos em que o uso de betametasona apresentou associação com ocorrência significativamente menor de complicações, foi calculado o número necessário para tratar para evitar o desfecho em um recém-nascido. Adotou-se significância de 5%. A média de idade gestacional foi de 29,4 semanas e, de peso, 794,2gramas. Os recém-nascidos cujas mães receberam betametasona apresentaram melhores índices de Apgar de primeiro minuto (p<0,001), uso de menos doses de surfactante exógeno (p=0,007), redução da freqüência de displasia broncopulmonar (p=0,02), persistência do canal arterial (p=0,002) e óbitos (p=0,008). As causas principais de óbito mais freqüentes foram hemorragia pulmonar e sepse, responsáveis por 64,5% do total dos óbitos. O número necessário para tratar relacionado à displasia broncopulmonar foi 3,2; à persistência do canal arterial, 2,4 e, ao óbito, de 2,8. O risco de óbito dos RN com uso antenatal de betametasona foi 60% menor do que aqueles sem essa terapia. A corticoterapia antenatal relacionou-se, de forma significativa, a melhores condições ao nascimento (com redução da freqüência de índices de Apgar de primeiro minuto inferiores a três); menos morbidade pós-natal (com uso de menor número de doses de surfactante exógeno, redução da ocorrência de displasia broncopulmonar e de persistência do canal arterial) e menor mortalidade. / A retrospective cohort study of 62 pregnancies with absent or reversed end-diastolic flow in the umbilical arteries was conducted in order to investigate the impact on postnatal outcome of a single course of antenatal betamethasone therapy for the acceleration of fetal lung maturation. Sixty-two singleton pregnancies, without fetal or neonatal anomalies, delivered during the period of January 2000 and July 2006 with a gestational age ranging from 26 to 34 weeks were included. The study included 31 newborns with the antenatal corticosteroid therapy and 31 nontreated, matched individually according to gestational age (within about six days), birth weight (within about 10%) and value of pulsatility index for veins in the ductus venosus (maximum of 1,0 or between 1,01 and 1,50). The outcomes assessed were: 1- and 5-minute Apgar scores, referral to the neonatal intensive care unit, need of tracheal intubation, use of continuous positive airway pressure, use of oxygen therapy, length of hospital stay, survival, in-hospital mortality (and main cause), use of surfactant, number of surfactant doses, and the occurrence of hyaline membrane disease, bronchopulmonary dysplasia, intracranial hemorrhage, retinopathy of prematurity, patent ductus arteriosus, necrotizing enterocolitis, early-onset and late-onset neonatal sepsis. Data from each matched-pair of infants were analyzed in terms of its discordance by the use of these tests: Student\'s t test for matched-pairs, McNemar´s chi-square test, symmetry test, Wilcoxon matched-pairs signed-ranks test, log-hank test. Numbers needed to treat in the case of beneficial effect were calculated for each outcome. A significance level of 5% was adopted for all tests. Mean of gestational age and birth weight were 29,4 weeks and 794,4grams. Infants whose mothers received antenatal betamethasone therapy had better 1-minute Apgar scores (p<0,001), use of fewer surfactant doses (p=0,007), reduction of the occurrence of bronchopulmonary dysplasia (p=0,02), patent ductus arteriosus (p=0,002) and in-hospital deaths (p=0,008). Pulmonary hemorrhage and sepsis were the two main causes of deaths (64,5% of the total of deaths). Number needed to treat related to bronchopulmonary dysplasia was 3,2; to patent ductus arteriosus was 2,4 and to in-hospital death was 2,8. The risk of death decreased of 60% by the use of antenatal steroid. Antenatal betamethasone therapy was significantly related to better birth conditions (reduction of 1-minute Apgar scores < 3), less morbidity (fewer surfactant doses and reduction on the occurrence of bronchopulmonary dysplasia and patent ductus arteriosus) and lower in-hospital mortality.
25

Ciclo único de betametasona para maturação pulmonar fetal em casos com diástole zero ou reversa: impacto em resultados pós-natais / Single course of antenatal betamethasone therapy for the acceleration of fetal lung maturation in absent or reversed end-diastolic velocity in the umbilical arteries: impact on postnatal outcomes

Luciana Carla Longo e Pereira 12 September 2007 (has links)
Para investigar o impacto em resultados pós-natais do uso de ciclo único de betametasona para maturação pulmonar em gestações (únicas, sem malformações fetais ou neonatais) com diástole zero ou diástole reversa à dopplervelocimetria das artérias umbilicais, foi conduzido estudo de coorte histórico com 62 recém-nascidos entre 26 e 34 semanas. Desses, 31 tinham uso antenatal do corticóide (nascidos entre maio de 2004 e julho de 2006) e 31 controles sem o uso da droga (nascidos entre janeiro de 2000 a março de 2004), pareados individualmente segundo índice de pulsatilidade para veias do ducto venoso (até 1,0 ou entre 1,01 e 1,50), idade gestacional ao nascimento (variação máxima de seis dias) e peso ao nascimento (variação máxima de 10%). Avaliaram-se: índice de Apgar de primeiro e quinto minutos, internação em unidade de terapia intensiva, uso de suporte respiratório (intubação orotraqueal, pressão positiva contínua nas vias aéreas, suplemento de oxigênio), tempo de internação, sobrevida, ocorrência de óbito (e causa principal), além da ocorrência de complicações (doença das membranas hialinas, displasia broncopulmonar, hemorragia intracraniana, retinopatia da prematuridade, persistência de canal arterial, enterocolite necrosante, sepse precoce e tardia). Fez-se análise estatística para os pares de recém-nascidos dos dois grupos, baseada na razão de pares discordantes e utilizaram-se os testes: t de Student para amostras pareadas, qui-quadrado de McNemar, de simetria assintótica, de Wilcoxon, de log-rank. No caso dos desfechos em que o uso de betametasona apresentou associação com ocorrência significativamente menor de complicações, foi calculado o número necessário para tratar para evitar o desfecho em um recém-nascido. Adotou-se significância de 5%. A média de idade gestacional foi de 29,4 semanas e, de peso, 794,2gramas. Os recém-nascidos cujas mães receberam betametasona apresentaram melhores índices de Apgar de primeiro minuto (p<0,001), uso de menos doses de surfactante exógeno (p=0,007), redução da freqüência de displasia broncopulmonar (p=0,02), persistência do canal arterial (p=0,002) e óbitos (p=0,008). As causas principais de óbito mais freqüentes foram hemorragia pulmonar e sepse, responsáveis por 64,5% do total dos óbitos. O número necessário para tratar relacionado à displasia broncopulmonar foi 3,2; à persistência do canal arterial, 2,4 e, ao óbito, de 2,8. O risco de óbito dos RN com uso antenatal de betametasona foi 60% menor do que aqueles sem essa terapia. A corticoterapia antenatal relacionou-se, de forma significativa, a melhores condições ao nascimento (com redução da freqüência de índices de Apgar de primeiro minuto inferiores a três); menos morbidade pós-natal (com uso de menor número de doses de surfactante exógeno, redução da ocorrência de displasia broncopulmonar e de persistência do canal arterial) e menor mortalidade. / A retrospective cohort study of 62 pregnancies with absent or reversed end-diastolic flow in the umbilical arteries was conducted in order to investigate the impact on postnatal outcome of a single course of antenatal betamethasone therapy for the acceleration of fetal lung maturation. Sixty-two singleton pregnancies, without fetal or neonatal anomalies, delivered during the period of January 2000 and July 2006 with a gestational age ranging from 26 to 34 weeks were included. The study included 31 newborns with the antenatal corticosteroid therapy and 31 nontreated, matched individually according to gestational age (within about six days), birth weight (within about 10%) and value of pulsatility index for veins in the ductus venosus (maximum of 1,0 or between 1,01 and 1,50). The outcomes assessed were: 1- and 5-minute Apgar scores, referral to the neonatal intensive care unit, need of tracheal intubation, use of continuous positive airway pressure, use of oxygen therapy, length of hospital stay, survival, in-hospital mortality (and main cause), use of surfactant, number of surfactant doses, and the occurrence of hyaline membrane disease, bronchopulmonary dysplasia, intracranial hemorrhage, retinopathy of prematurity, patent ductus arteriosus, necrotizing enterocolitis, early-onset and late-onset neonatal sepsis. Data from each matched-pair of infants were analyzed in terms of its discordance by the use of these tests: Student\'s t test for matched-pairs, McNemar´s chi-square test, symmetry test, Wilcoxon matched-pairs signed-ranks test, log-hank test. Numbers needed to treat in the case of beneficial effect were calculated for each outcome. A significance level of 5% was adopted for all tests. Mean of gestational age and birth weight were 29,4 weeks and 794,4grams. Infants whose mothers received antenatal betamethasone therapy had better 1-minute Apgar scores (p<0,001), use of fewer surfactant doses (p=0,007), reduction of the occurrence of bronchopulmonary dysplasia (p=0,02), patent ductus arteriosus (p=0,002) and in-hospital deaths (p=0,008). Pulmonary hemorrhage and sepsis were the two main causes of deaths (64,5% of the total of deaths). Number needed to treat related to bronchopulmonary dysplasia was 3,2; to patent ductus arteriosus was 2,4 and to in-hospital death was 2,8. The risk of death decreased of 60% by the use of antenatal steroid. Antenatal betamethasone therapy was significantly related to better birth conditions (reduction of 1-minute Apgar scores < 3), less morbidity (fewer surfactant doses and reduction on the occurrence of bronchopulmonary dysplasia and patent ductus arteriosus) and lower in-hospital mortality.
26

External otitis and its treatment : is a group III steroid without antibiotics sufficent therapy? Experimental and clinical studies

Emgård, Per January 2005 (has links)
ABSTRACT External otitis and its treatment. Is a group III steroid without antibiotics sufficient therapy? – Experimental and clinical studies Per Emgård, Department of Otorhinolaryngology, University of Umeå and Ystad Hospital, Umeå and Ystad, Sweden External otitis is one of the most common ear, nose and throat (ENT) diagnoses in out-patient clinics. The clinical course of external otitis includes itching, pain, redness, swelling and effusion of the external auditory canal (EAC) with normal tympanic membrane status. The inflammatory condition is often associated with infection by bacteria, e.g. Pseudomonas aeruginosa, or skin bacteria such as Staphylococcus species. Fungi are present only in a low percentage of cases and if present Candida albicans infection is the most frequent in northern countries such as Sweden and the UK. Topical therapy is recommended in most countries and dominates the therapy in most studies. Topical drugs used are usually a combination of antibiotics and a steroid. However, external otitis is treated with surprisingly many strategies – eleven different ones in Sweden, for example, and 18 in the UK. The aims of the present studies were to – -establish an animal model, infected and uninfected, suitable for testing various treatment strategies of external otitis; and -perform a clinical study in patients to elucidate whether a group III steroid alone is as efficient for treatment of external otitis as is the commonly used topical drug containing a combination of a steroid and antibiotics. The animal model was established through mechanical irritation of the external ear canal skin of Sprague-Dawley rats. An evaluation scale for characterization of the clinical status of the ear canal was introduced, recording redness, swelling and occurrence of effusion in a standardized way. Specimens of the ear canal skin were analysed by histological techniques. A topical solution of 0.05% bethametasone dipropionate (BD) was compared with a 1% hydrocortisone solution with antibiotics oxytetracycline and polymyxin B added (HCPB), administered in the external otitis model infected or non-infected with bacteria (P. aeruginosa) and a fungus (C. albicans). The same drugs were tested in a randomized parallel-group multi-centre study in 51 patients. The clinical status of the external otitis patients was evaluated on a similar scale as used in the animal model. Early normalization of the ear canal skin status and frequency of relapses during the 6-month follow-up period were used as end-points of the study. The studies showed the following: -An animal model for external otitis, infected or uninfected, could be established. -A new scale for evaluation of the external ear canal status with regard to redness, swelling and occurrence of effusion was introduced for the animal model as well as for the investigations in patients. -Treatment with a group III steroid topical solution without antibiotics was superior to treatment with a group I steroid with antibiotics added in achieving resolution of external otitis. -The effectiveness of the topical drugs in the clinical studies in external otitis patients was similar to that in animal external otitis models. We conclude that a group III steroid solution cures external otitis more effectively than does a solution containing a group I steroid combined with antibiotics, whether infected by bacteria or by fungi. No difference was evident regarding adverse effects. Furthermore, costs favour a solution without any antibiotic components. In view of these observations a group III steroid solution is preferred for remedy of external otitis in the clinical situation. Key words: external otitis, external auditory canal (EAC), animal model, treatment, betamethasone, hydrocortisone, antibiotics, human study, Pseudomonas aeruginosa, Candida albicans.
27

Développement et évaluation de nouvelles formulations à libération prolongée à base de microparticules de PLGA en vue d'une administration intra-articulaire dans le traitement de pathologies inflammatoires / Development and evaluation of new PLGA microparticles controlled-release formulations for an intraarticular delivery in inflammatory diseases.

Gaignaux, Amélie 25 November 2013 (has links)
L’arthrose et l’arthrite rhumatoïde sont deux pathologies articulaires caractérisées par la dégradation du cartilage articulaire, subséquente à la production de divers médiateurs inflammatoires. Le traitement de ces pathologies se limite généralement à soulager le patient des épisodes douloureux et inflammatoires et à améliorer sa qualité de vie. Dans le cas de l’arthrose, peu de traitements permettent d’enrayer significativement l’évolution de la dégradation du cartilage et donc de la maladie. Par contre, l’arthrite rhumatoïde peut être efficacement ralentie grâce à l’administration de certaines molécules. Néanmoins, ces traitements n’ont généralement montré qu’une efficacité à court-terme, requérant une administration fréquente. L’objectif de ce travail repose donc sur l’élaboration de nouvelles options thérapeutiques permettant de réduire la fréquence d’administration ainsi que les effets indésirables des traitements actuels. La délivrance de molécules en intra-articulaire associée à une libération prolongée offre l’avantage d’exposer les sites directement impliqués dans l’évolution de la maladie à une ou plusieurs molécules efficaces contre l’inflammation et la douleur, et aidant à la régénération du cartilage, durant plusieurs semaines, voire des mois.<p>Des microparticules de PLGA chargées en clonidine ou en bétaméthasone ont donc été optimisées afin d’obtenir des efficacités d’encapsulation appréciables (clonidine HCl :EE ≈ 20% ;dipropionate de bétaméthasone :EE ≈ 70%), une taille adaptée à l’administration intra-articulaire (12 – 38 µm) et une libération de la molécule s’échelonnant sur 5 à 8 semaines. La libération prolongée de la clonidine implique des mécanismes de diffusion de la molécule ainsi que de dégradation/érosion du polymère. Au vu de l’absence de réaction inflammatoire, les microparticules développées sont correctement tolérées par les chondrocytes, synoviocytes, PBMC et neutrophiles, principales cellules impliquées dans les mécanismes inflammatoires de l’arthrose et de l’arthrite rhumatoïde. L’évaluation de l’efficacité anti-inflammatoire des microparticules vides et chargées en clonidine ou en bétaméthasone via l’étude de l’expression et de la sécrétion de différents médiateurs de l’inflammation a permis d’aboutir à plusieurs conclusions :(i) les microparticules vides sont associées à un effet anti-inflammatoire, (ii) les microparticules chargées en clonidine n’ont pas montré d’activité anti-inflammatoire propre pouvant être attribuée à la clonidine, et (iii) les microparticules de bétaméthasone ont confirmé l’effet anti-inflammatoire de la bétaméthasone. Enfin, l’étude de la toxicité des principes actifs et microparticules vides ou chargées a montré une toxicité significative de la clonidine sur les synoviocytes. Néanmoins, l’encapsulation des principes actifs dans les microparticules de PLGA a permis d’éliminer cette toxicité, protégeant donc efficacement les cellules articulaires.<p>Les microparticules développées permettent alors d’envisager l’encapsulation d’autres molécules anti-inflammatoires ou une combinaison de molécules ayant des effets complémentaires (anti-inflammatoire et antidouleur). L’utilisation de la clonidine dans ces indications devra être réévaluée en étudiant de façon approfondie son efficacité dans la douleur. / Both osteoarthritis and rheumatoid arthritis are articular diseases characterized by the degeneration of the joint cartilage, resulting from the production of various inflammatory mediators. The current treatment of these diseases is restricted to alleviate the painful and inflammatory episodes of the patients and to improve its quality of life. In osteoarthritic patients, few treatments allow to significantly stop the evolution of the degradation of the cartilage and, consequently, the disease. In rheumatoid arthritis, the evolution can be slowed down following the administration of some drugs. Nevertheless, these treatments are often associated to a short-term efficacy. The objective of this work is to develop new therapeutic options that allow to reduce the frequency of administration and the side effects of the current treatments. The intraarticular delivery combined to controlled-release presents the advantage to expose the sites directly involved in the evolution of the disease to one or more molecules effective to relieve the pain, inflammation and to help the regeneration of the cartilage.<p>Clonidine or betamethasone-loaded PLGA microparticles were optimized to reach suitable encapsulation efficiencies (clonidine HCl: EE ≈ 20%; betamethasone dipropionate: EE ≈ 70%), an appropriate size for an intraarticular delivery (12 – 38 µm) and a controlled-release of the molecule over 5 to 8 weeks. The release of clonidine implies mechanisms of diffusion and degradation/erosion of the polymer. Given the absence of an inflammatory reaction, the developed microparticles were properly tolerated by the chondrocytes, synoviocytes, PMBC and neutrophils, which are the main cells involved in the inflammatory reaction of osteoarthritis and rheumatoid arthritis. The assessment of the anti-inflammatory efficacy of the drug-free and drug-loaded microparticles through the evaluation of the expression and the secretion of various inflammatory mediators allowed to draw several conclusions: (i) drug-free microparticles were associated to an anti-inflammatory effect, (ii) clonidine-loaded microparticles did not show any anti-inflammatory activity that could be attributed to clonidine, and (iii) betamethasone- loaded microparticles confirmed the anti-inflammatory effect of betamethasone. Finally, the evaluation of the toxicity of the drugs and microparticles showed a significant toxicity of clonidine against synoviocytes. Nevertheless, the encapsulation of the drugs in PLGA microparticles induced the suppression of this toxicity, protecting in this way the articular cells. <p>Entrapping other anti-inflammatory molecules or a combination of molecules with complementary effects (anti-inflammatory and anti-nociceptive drugs) in the PLGA microparticles developed has to be considered. Moreover, the use of clonidine in these indications has to be reassessed by a thorough study of its anti-nociceptive potential.<p><p> / Doctorat en Sciences biomédicales et pharmaceutiques / info:eu-repo/semantics/nonPublished
28

Glucocorticoid receptors in inflammatory skin diseases:the effect of systemic and topical glucocorticoid treatment on the expression of GRα and GRβ

Kubin, M. (Minna) 29 November 2016 (has links)
Abstract Glucocorticoids are the most important and widely used treatment modality in dermatology. A large variety of topical as well as systemic preparations is available. Most patients treated with glucocorticoids respond quickly to the treatment, but some are considered insensitive or even resistant to glucocorticoid therapy. Currently, there is no known measurable variable, through which the response can be predicted. Glucocorticoids mediate their actions through glucocorticoid receptors (GR). Several isoforms of GR exist, but the α (GRα) and β (GRβ) isoforms are clinically the most important. Based on previous studies, it has been proposed that the abundance of GR isoforms or the GRβ: GRα –ratio could affect individual responsiveness to corticosteroid treatment. In particular, up-regulation of GRβ expression has been shown to be linked to resistance to corticosteroid treatment. This thesis comprises three sub-studies. Firstly, we wanted to determine whether GRα and GRβ are expressed in inflammatory skin diseases. Secondly, we examined if the expression is altered by corticosteroid treatment in eczema atopicum, bullous pemphigoid and psoriasis. Finally, we measured the effects of a topical vitamin D3 analogue (calcipotriol) combined with betamethasone compared with betamethasone monotherapy on inflammatory biomarkers of psoriasis. Our studies provide detailed novel data about the expression of GRα and GRβ. GRα and GRβ were shown to be expressed in the blood lymphocytes and lesional skin of patients with eczema atopicum, bullous pemphigoid and psoriasis, as well as in the skin of patients with eczema nummulare, lichen simplex chronicus and lichen ruber planus. Systemic corticosteroid treatment was shown to affect the expression of GRα and GRβ in eczema atopicum and bullous pemphigoid, but the inconsistent variation in their expression between patients prevented us from drawing firm conclusions. Neither GRα nor GRβ as a single marker were found to be a suitable predictor of corticosteroid responsiveness. Clinical and laboratory analyses showed that topical treatment of psoriasis with calcipotriol/betamethasone combination ointment is more beneficial measured by both than betamethasone monotherapy. / Tiivistelmä Glukokortikoideja (”kortisoni”) käytetään tulehduksellisten ihotautien hoidossa paikallisesti tai systeemisenä lääkkeenä. Suurin osa potilaista reagoi hoitoon nopeasti, mutta osalla hoitovaste on heikompi tai ilmenee hitaasti. Tällä hetkellä ei tunneta keinoja ennustaa luotettavasti kortisonihoidon vastetta. Glukokortikoidit vaikuttavat elimistössä glukokortikoidireseptorien (GR) kautta. Glukokortikoidireseptorista tunnetaan useita alatyyppejä, joista tärkeimmät ovat α (GRα) ja β (GRβ). Aiemman tiedon pohjalta on pidetty mahdollisena, että GR-alatyyppien suhteella tai määrällä on merkitystä kortisonivasteen syntymisessä. Erityisesti on arveltu, että ylimäärä GRβ:aa voisi estää kortisonihoidon vaikutusta. Tässä väitöskirjassa tavoitteena on ollut selvittää, tapahtuuko GR-alatyyppien ilmenemisessä muutoksia tulehduksellisia ihosairauksia sairastavilla potilailla sekä tutkia, miten kortisonihoito vaikuttaa GR-tasoihin atooppista ihottumaa, pemfigoidia ja psoriaasia sairastavilla potilailla. Lisäksi olemme verranneet paikallishoitoa pelkällä kortisonivoiteella D-vitamiinijohdos kalsipotriolin ja kortisonin yhdistelmähoitoon psoriaatikoilla. Tutkimus on antanut uutta yksityiskohtaista tietoa GRα:n ja GRβ:n esiintymisestä ihossa ja tulehdussoluissa ihosairauksia sairastavilla potilailla. Tutkimustulosten perusteella voidaan todeta, että GRα ja GRβ esiintyvät atooppista ihottumaa, pemfigoidia ja psoriaasia sairastavien potilaiden ihossa ja veren tulehdussoluissa sekä nummulaari-ihottumaa, neurodermatiittia ja punajäkälää sairastavien potilaiden ihossa. Suun kautta annettu kortisonihoito vaikuttaa GRα- ja GRβ–lähetti-RNA:n ilmenemiseen, mutta potilaskohtaiset erot ovat suuret, eikä kumpikaan, GRα tai GRβ, sovellu yksinään ennustamaan kortisonihoidon vastetta. Paikallisella kortisonihoidolla D-vitamiinijohdos kalsipotrioliin yhdistettynä on suotuisampi vaikutus psoriaasin tulehduksellisiin välittäjäaineisiin ja tulehdussoluihin kuin pelkällä paikallisella kortisonihoidolla.
29

Development and evaluation in vitro and in vivo of injectable hydrolipidic gels with sustained-release properties for the management of articular pathologies / Développement et évaluation in vitro et in vivo de gels hydrolipidiques injectables à libération prolongée pour le traitement de pathologies articulaires

Reeff, Jonathan 25 June 2014 (has links)
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

Page generated in 0.0505 seconds