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  • 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.
1

Investigations On The Biodegradable Polymeric And Inorganic Substrates For Controlled Drug Delivery And Bone And Cartilage Repair

Aycan, Gunay 01 February 2008 (has links) (PDF)
Tissue engineering is an interdisciplinary field that seeks to address the needs by applying the principles of chemistry, biology and engineering for the development of viable substitutes that restore and maintain the function of human bone and cartilage tissues. In tissue engineering, scaffolds play an important role as temporary supports for the transplantation of specific cells and tissues. In this study, poly(ester-urethane)urea (PEUU) and poly(caprolactone) (PCL) scaffolds were fabricated. Scaffolds were characterized by SEM. Porosities of scaffolds vary from 67 % to 80 %. Controlled drug delivery systems release drugs at predetermined rates for extended periods. In this study / firstly poly(lactic-co-glycolicolide/tricalcium phosphate) (PLGA/TCP) and poly(L-lactide)/tricalcium phosphate (PLLA/TCP) composites loaded with Gentamicin or Vancomycin were prepared as controlled drug delivery systems for the local treatment of osteomyelitis. The release behavior of drugs were monitored by UV-VIS spectrometer. It was shown that, Vancomycin loaded samples released higher amounts of drug than the samples loaded with Gentamicin. Secondly, porous ceramic samples were coated with PLGA and PLLA and they were loaded with dexamethasone. The release behavior of samples were monitored by UV-VIS spectrometer.The cubic ceramics released higher amounts of dexamethasone than cylindrical ceramics. When the mechanical properties of porous ceramic samples were concerned, PLLA coated samples had better mechanical properties.
2

Imprégnation supercritique pour l'élaboration de systèmes à libération prolongée / Supercritical impregnation for the elaboration of controlled drug delivery systems

Bouledjouidja, Abir 29 January 2016 (has links)
Le procédé d’imprégnation en milieu supercritique est une alternative « propre » à l’imprégnation par voie liquide. Entre autres applications, les procédés d’imprégnation peuvent être utilisés pour l’élaboration de systèmes de délivrance de médicaments appliqués aux domaines pharmaceutique et médical. Cette étude porte sur l’élaboration de systèmes de délivrance de médicaments en utilisant l'imprégnation supercritique des principes actifs sur deux types de supports : des matrices polymériques (lentilles intraoculaires) et des matrices poreuses (silices mésoporeuses). Dans le premier cas, des lentilles polymériques intraoculaires (IOLs), utilisées pour la chirurgie de la cataracte, ont été imprégnées par des principes actifs : un anti-inflammatoire (Dexaméthasone 21-phosphate disodium: DXP) et un antibiotique (Ciprofloxacine: CIP). Plus particulièrement, deux types de lentilles ont été étudiés : des IOLs rigides à base de PMMA et des IOLs souples à base de P-HEMA. Les expériences d'imprégnation supercritique ont été effectuées en mode batch et les taux d'imprégnation ont été déterminés par des études de cinétique de relargage des principes actifs. L’influence des conditions opératoires sur l’efficacité de l’imprégnation a été étudiée en réalisant des expériences d’imprégnation préliminaires suivies par des plans d’expériences par la suite. Dans le second cas, une silice mésoporeuse a été utilisée comme support d’imprégnation pour un médicament faiblement hydrosoluble (Fénofibrate), afin d’augmenter sa cinétique de dissolution. L’imprégnation supercritique a été effectuée avec le CO2 pur en faisant varier la pression et le taux de dépressurisation (rapide et lent). / Supercritical impregnation is an attractive “clean” alternative to conventional impregnation processes using generally liquid organic solvents. Among other applications, the impregnation process can be used for the development of controlled drug delivery systems applied to the pharmaceutical and medical fields. This work focuses on the preparation of controlled drug delivery systems using supercritical impregnation of drugs in two kinds of impregnation supports: polymeric matrices (intraocular lenses) and porous supports (mesoporous silica). Firstly, the supercritical impregnation of polymeric intraocular lenses (IOLs), used in cataract surgery, by an anti-inflammatory drug (Dexamethasone 21-phosphate disodium: DXP) and an antibiotic (Ciprofloxacin: CIP), is studied. More particularly, two polymeric IOLs were tested: rigid intraocular lenses made from derivative of PMMA and foldable intraocular lenses made from derivative of P-HEMA. Supercritical impregnations were carried out in a batch mode and the impregnation yields were determined through drug release kinetics studies in a solution simulating the aqueous humor. The influence of operating conditions on impregnation was studied by performing preliminary impregnation experiments followed by experimental designs. The second part of this work deals with the loading of a poorly water-soluble drug (Fenofibrate) in a mesoporous silica for improving drug dissolution kinetics. Supercritical impregnations were carried out with pure CO2 at different pressures (100 to 200 bar) and depressurization rates (rapid and slow).

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