Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2016-11-11T17:07:10Z No. of bitstreams: 0 / Made available in DSpace on 2016-11-11T17:07:10Z (GMT). No. of bitstreams: 0 / Nas últimas décadas tem aumentado o interesse pelos enxertos de pele humana radioesterilizadas, para aplicação principalmente em queimaduras extensas e profundas. Isto se deve ao fato destes enxertos apresentarem rápida aderência e menor potencial antigênico, em comparação com os demais tratamentos utilizados. A proposta deste estudo foi avaliar a histoarquitetura do enxerto de pele humana irradiada com doses de 25 kGy, 50 kGy e não irradiada, durante o processo de reparação tecidual, em camundongos Nude submetidos a enxertia de pele na região dorsal. Três grupos de animais receberam enxertos de pele humana irradiada (25 kGy e 50 kGy) e não irradiada e foram eutanasiados no 3º, 7º e 21º dia após a realização da cirurgia. Após os procedimentos histológicos de rotina, as amostras de tecido foram coradas com hematoxilina e eosina (HE) para a quantificação de queratinócitos, fibroblastos, células de defesa e vasos sanguíneos e a reação de imunofluorescência (IF) foi realizada para a determinação da expressão de colágeno do tipo I humano e do colágeno dos tipos I e III de camundongo. A quantificação, tanto das células quanto dos tipos de colágeno foi realizada por análise de imagem, utilizando o programa Image-Pro PLus 6.0. Os resultados histológicos demostraram que a pele humana irradiação, quando enxertada, influencia o aumento do número de células no local de cicatrização ao longo do tempo, principalmente na dose de 25 kGy, além de proporcionar uma melhor dispersão destas células. No 21º dia, os três grupos de animais com enxertia de pele humana tiveram parte do enxerto incorporado no processo de cicatrização. O grupo não irradiado apresentou maior incorporação do enxerto (43%), porém menor produção de colágeno do tipo III de camundongo (22%). Já os grupos com enxertia de pele irradiada apresentaram menor incorporação do enxerto (6 e 15%), mas com maior produção de colágeno do tipo III de camundongo (35% e 28%, para 25 kGy e 50 kGy, respectivamente). Com este estudo pôde-se concluir que o grupo irradiado a 25 kGy, apresenta maior proliferação celular e formação de vasos,além de melhor remodelamento da região de cicatrização. / Dissertação (Mestrado em Tecnologia Nuclear) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

<p>Raloksifen je predstavnik selektivnih modulatora estrogenih receptora koji se koristi u terapiji osteoporoze i invazivnog oblika raka dojke u postmenopauzi. Raloksifen se relativno dobro resorbuje iz gastrointestinalnog trakta, ali pri prvom prolasku kroz jetru podleže biotransformaciji u značajnom procentu, &scaron;to je uzrok njegove niske biolo&scaron;ke raspoloživosti. Bioraspoloživost kod ljudi iznosi 2%, a kod Wistar pacova 39%. Različite supstance se koriste da bi se pobolj&scaron;ala bioraspoloživost lekova. Žučne kiseline, kao &scaron;to je deoksiholna kiselina, omogućavaju bolji prolazak kroz biolo&scaron;ke membrane drugim supstancama, te mogu povećati bioraspoloživost lekova. Apigenin je &scaron;iroko rasprostranjeni flavonoid koji inhibi&scaron;e različite metaboličke puteve i na taj način može usporiti metabolizam i eliminaciju i povećati koncentraciju lekova u krvi. Ciljevi ovog istraživanja su bili da se ispita da li apigenin i natrijum-deoksiholat mogu povećati bioraspoloživost raloksifena, njihov uticaj na biohemijske parametre i parametre hemostaze, kao i da se ispita antioksidativni potencijal apigenina. Ispitan je i uticaj apigenina na akutno o&scaron;tećenje jetre usled primene toksične doze paracetamola. U istraživanju su kori&scaron;ćeni zdravi, beli pacovi mu&scaron;kog roda, soja Wistar. U ogledu su ukupno kori&scaron;ćene 84 eksperimentalne životinje. Sva ispitivanja na životinjama je odobrila Etička komisija Univerziteta u Novom Sadu. Raloksifen je primenjen intravenski i per os, dok su natrijum-deoksiholat i apigenin aplikovani peroralno. Uzorci krvi, urina i fecesa su kori&scaron;ćeni za određivanje farmakokinetskih parametara, dok su za određivanje biohemijskih, hemostatskih i parametara oksidativnog stresa kori&scaron;ćeni serum i uzorci jetre laboratorijskih životinja. Pretretman natrijum-deoksiholatom je doveo do smanjenja koncentracije raloksifena u krvi zbog olak&scaron;anog i brzog prodora raloksifena u periferne kompartmane. Time je značajno produženo poluvreme eliminacije i srednje vreme zadržavanja raloksifena i značajno je povećan volumen distribucije raloksifena. Apigenin je doveo do manjeg pada koncentracije raloksifena u prvim satima nakon intravenske primene raloksifena, dok su koncentracije raloksifena bile značajno vi&scaron;e nakon osmog časa od primene leka. Uticaj raloksifena na biohemijske parametre je bio značajno veći nakon intravenske nego nakon peroralne primene. Nakon intravenske primene raloksifena je značajno povećana aktivnost enzima jetre, ALP, ALT, AST i GGT, dok su pokazatelji funkcije bubrega, urea, mokraćna kiselina i kreatinin bili sniženi. U grupama koje su pretretirane natrijum-deoksiholatom i apigeninom vrednosti ovih parametara bile su niže u odnosu na grupu tretiranu samo raloksifenom. Statistički najznačajniji uticaj je imala primena trojne kombinacije, raloksifena, natrijum-deosiholata i apigenina, koja je dovela do značajnog pada aktivnosti enzima jetre, i u odnosu na grupu tretiranu raloksifenom i u odnosu na kontrolnu grupu. Kod životinja tretiranih kombinacijom apigenina i paracetamola pokazatelji toksičnosti su bili značajno niži, naročito vrednosti ALT i ALP, u odnosu na grupu koja je dobijala samo paracetamol. Hepatotoksičnost izazvana toksičnom dozom paracetamola je potvrđena i histopatolo&scaron;kim promenama na jetri, koje nisu primećene u grupi životinja tretiranih kombinacijom apigenina i paracetamola. Ispitivanjem je utvrđeno da apigenin može da spreči paracetamolom indukovano povećanje nivoa MDA, &scaron;to ukazuje da apigenin pozitivno utiče na očuvanje integriteta ćelije. Aktivnost enzima CAT i GR u homogenatima jetre je bila značajno povećana nakon primene toksične doze paracetamola u odnosu na kontrolnu grupu. Aktivnost enzima CAT i GR u grupi tretiranoj kombinacijom apigenina i paracetamola je bila približna vrednostima u kontrolnoj grupi. Na osnovu rezultata istraživanja može se zaključiti da natrijum-deoksiholat i apigenin značajno utiču na farmakokinetiku raloksifena. Primena natrijum-deoksiholata dovela je do pada koncentracije raloksifena u krvi, značajnog prelaska raloksifena iz krvi u periferne kompartmane i povećanja njegovog volumena distribucije, dok je apigenin značajno usporio metabolizam i eliminaciju raloksifena i doveo do njegovog produženog zadržavanja u krvi. Natrijum-deoksiholat i apigenin su pokazali pozitivan uticaj na biohemijske parametre, parametre hemostaze i smanjenje nivoa oksidativnog stresa. Kombinacija natrijum-deoksiholata i apigenina je pokazala sinergistički uticaj na navedene parametre, odnosno dovela je do značajnih promena u odnosu na pojedinačnu primenu ovih supstanci. Rezultati ispitivanja ukazuju na to da apigenin smanjuje stepen lipidne peroksidacije i da dovodi do značajnog povećanja enzimskih antioksidantnih mehanizama odbrane kod pacova kod kojih je hepatotoksičnost indukovana paracetamolom.</p> / <p>Raloxifene is selective estrogen receptor modulator used in treatment of osteoporosis and invasive breast cancer in postmenopausal women. Raloxifene is well absorbed from the gastrointestinal tract, but undergoes extensive first-pass metabolism, which results in very low bioavailability of raloxifene, 2% in humans, and 39% in Wistar rats. Various supstances are used for increasing bioavailability of other drugs. Bile acids, such as deoxycholic acid, promote transport of other supstances through biological membranes, and consequently, may increase their bioavailability. Apigenin is a widespread flavonoid, which inhibits different metabolic pathways. Thus, apigenin can slow down metabolism and elimination of drugs, and raise drug concentration in blood. Aims of this study were to investigate if apigenin and sodium deoxycholate could increase bioavailability of raloxifene, their influence on biochemical and hemostasis parameters, and to investigate antioxidative potential of apigenin. Furthermore, influence of apigenin on acute liver damage after toxic dose of paracetamol was examined. In vivo experiments were performed on 84 laboratory healthy male Wistar rats. All experiments were approved by Ethics Committee of University of Novi Sad. Raloxifene was applied intravenously and per os, while sodium deoxycholate and apigenin were given perorally. Blood, urine and feces samples were used for pharmacokinetic parameters measurement, whereas serum and liver samples were used for evaluation of biochemical, hemostasis and oxidative stress parameters. Pretreatment of sodium deoxycholate led to raloxifene blood concentration decrease due to easier penetration of raloxifene in peripher compartments. As a result, raloxifene half-life and mean residence time were significantly longer and volume of distribution was increased. Apigenin caused lower decrease in raloxifene concentration in first few hours after raloxifene intravenous application, while raloxifene concentrations after apigenin pretreatment were significantlny higher 8 hours after raloxifene application. Influence of raloxifene on biochemical parameters was more significant after intravenous than after per os application. Intravenous application of raloxifene led to increased activity of liver enzymes, ALP, ALT, AST and GGT, while parameters of kidney function, urea, uric acid and creatinine were decreased in comparison to the control group. In experimental groups pretreated with sodium deoxycholate and apigenin these parameters were lower than in the group treated only with raloxifene. Statistically the most significant effects were in the group treated with combination of raloxifene, sodium deoxycholate and apigenin, which caused significant decrease in activity of liver enzymes compared both with raloxifene and control group of animals. In experimental animals treated with combination of apigenin and paracetamol bioindicators of paracetamol toxicity were significantly lower, especially activity of ALT and ALP, in comparison to the group treated only with paracetamol. Hepatotoxicity induced by toxic dose of paracetamol was also confirmed by histopathological alterations in liver, which were not observed in the experimental group treated with combination of apigenin and paracetamol. In this study it was confirmed that apigenin could prevent paracetamol-induced MDA level increase, which suggests that apigenin have positive effects on cell integrity. Activity of CAT and GR in liver homogenates was significantly increased after toxic dose of paracetamol in comparison to the control group, while activity of these enzymes in the group treated with apigenin and paracetamol was similar to values in the control group. Results of this study showed that sodium deoxycholate and apigenin can significantly change pharmacokinetic parameters of raloxifene. Sodium deoxycholate caused signicant decrease in raloxifene blood concentration, extensive distribution from blood to peripheral compartments and increase of raloxifene volume of distribution. Apigenin inhibited metabolism and elimination of raloxifene and thus prolonged half-life and mean residence time of raloxifene. Sodium deoxycholate and apigenin showed positive effects on biochemical and hemostasis parameters and decreased the level oxidative stress. Combination of sodium deoxycholate and apigenin showed synergistic effects on these parameters in comparison to effects of separate application of sodium deoxycholate and apigenin. The result of our study indicates that apigenin inhibits the level of lipid peroxidation and significantly increase the enzyme antioxidant defence mehanisms in paracetamol induced hepatotoxicity in rats.</p>

No / OBJECTIVES: To compare the properties of solid dispersions of felodipine for oral bioavailability enhancement using two different polymers, polyvinylpyrrolidone (PVP) and hydroxypropyl methylcellulose acetate succinate (HPMCAS), by hot-melt extrusion (HME) and spray drying. METHODS: Felodipine solid dispersions were prepared by HME and spray drying techniques. PVP and HPMCAS were used as polymer matrices at different drug : polymer ratios (1 : 1, 1 : 2 and 1 : 3). Detailed characterization was performed using differential scanning calorimetry, powder X-ray diffractometry, scanning electron microscopy and in-vitro dissolution testing. Dissolution profiles were evaluated in the presence of sodium dodecyl sulphate. Stability of different solid dispersions was studied under accelerated conditions (40 degrees C/75% RH) over 8 weeks. KEY FINDINGS: Spray-dried formulations were found to release felodipine faster than melt extruded formulations for both polymer matrices. Solid dispersions containing HMPCAS exhibited higher drug release rates and better wettability than those produced with a PVP matrix. No significant differences in stability were observed except with HPMCAS at a 1 : 1 ratio, where crystallization was detected in spray-dried formulations. CONCLUSIONS: Solid dispersions of felodipine produced by spray drying exhibited more rapid drug release than corresponding melt extruded formulations, although in some cases improved stability was observed for melt extruded formulations.