{"id":{"repo_id":"aachen","oai_identifier":"oai:publications.rwth-aachen.de:59577"},"canonical_url":"https://search.dev.ndltd.org/etd/aachen/oai:publications.rwth-aachen.de:59577","repository":{"repo_id":"aachen","name":"RWTH Aachen University","base_url":"https://publications.rwth-aachen.de/oai2d"},"display":{"title":"Freisetzungsverhalten von unterschiedlich hydrophil/hydrophoben Modellsubstanzen aus Poly-(D,L-lactid)- und Poly-(D,L-lactid)-co-PEO-co-poly-(D,L-lactid)-Mikrosphären und pharmazeutische Anwendungen","abstract":"Within the scope of this dissertation, the release behaviour of different model substances and drugs from degradable poly-(D,L-lactide) (PDLLA) and poly-(D,L-lactide)-co-PEO-co-poly-(D,L-lactide) (ABA) microspheres as well as poly-(D,L-lactide-co-TMC)(90:10) nanospheres in PBS-buffer are characterised. To investigate the release behaviour, three different hydrophilic/hydrophobic benzophenone based model substances were chosen; 2,2’-dihydroxy-4,4’-dimethoxy-benzophenone-5,5’-disodium-sulfonate (Uvinul DS-49™), 2,2’,4,4’-tetrahydroxy-benzophenone (Uvinul D-50™) and 2-hydroxy-4-methoxy-benzophenone (Uvinul M-40™). The ABA-triblock copolymer was synthesized by ring opening polymerisation of lactide in the presence of polyethyleneoxide (PEO, 2000) as an initiator and tin(II)-2-ethylhexanoate as a catalyst. PDLLA and ABA-triblockcopolymer microspheres were made according to the o/w-solvent-evaporation method. The three model substances DS-49, D-50 and M-40 were incorporated with a theoretical loading of 9, 13 and 17 weight% respectively. The resultant microspheres were, depending on the particle size distribution, separated into two or three particle fractions in the range of 100-300µm, 300-710µm and if available 710-1000µm. The release behaviour was investigated depending on the particle size, the loading, the model substance and the polymeric matrix. Furthermore, the degradation behaviour of the 300-710µm ranged PDLLA- and ABA-microspheres was investigated depending on the qualitative and quantitative loading for three weeks. A 100-day value was determined additionally to estimate tendencies. In doing so, a dependency of the incorporated substance to the degradation behaviour of the polymer can be observed. Another part of this work deals with the production of a drug release system for use in ophthalmology. To treat proliferative vitreoretinopathy (PVR) a drug release system is required to prevent an undesired proliferation of retinal pigment epithel cells (RPE cells) on the retina. Ascorbic acid loaded PDLLA microspheres were made according to the o/w-solvent-evaporation method. These spheres were tested in an in vitro drug release experiment. Furthermore the incorporation of nanospheres into an e-PTFE foil covered stent for use in angioplasty is described in this work. Spherical nanoparticles made of poly(D,L lactide-co-TMC) (90:10) were designed in different size-distributions via the o/w solvent evaporation process. The nanosphere suspensions were pressed with pressure through an e-PTFE covered stent to obtain a foil loaded with nanoparticles. The release behaviour of the dexamethasone or paclitaxel loaded nanospheres incorporated in the stent was investigated in an in vitro experiment.","abstract_html":"Within the scope of this dissertation, the release behaviour of different model substances and drugs from degradable poly-(D,L-lactide) (PDLLA) and poly-(D,L-lactide)-co-PEO-co-poly-(D,L-lactide) (ABA) microspheres as well as poly-(D,L-lactide-co-TMC)(90:10) nanospheres in PBS-buffer are characterised. To investigate the release behaviour, three different hydrophilic/hydrophobic benzophenone based model substances were chosen; 2,2’-dihydroxy-4,4’-dimethoxy-benzophenone-5,5’-disodium-sulfonate (Uvinul DS-49™), 2,2’,4,4’-tetrahydroxy-benzophenone (Uvinul D-50™) and 2-hydroxy-4-methoxy-benzophenone (Uvinul M-40™). The ABA-triblock copolymer was synthesized by ring opening polymerisation of lactide in the presence of polyethyleneoxide (PEO, 2000) as an initiator and tin(II)-2-ethylhexanoate as a catalyst. PDLLA and ABA-triblockcopolymer microspheres were made according to the o/w-solvent-evaporation method. The three model substances DS-49, D-50 and M-40 were incorporated with a theoretical loading of 9, 13 and 17 weight% respectively. The resultant microspheres were, depending on the particle size distribution, separated into two or three particle fractions in the range of 100-300µm, 300-710µm and if available 710-1000µm. The release behaviour was investigated depending on the particle size, the loading, the model substance and the polymeric matrix. Furthermore, the degradation behaviour of the 300-710µm ranged PDLLA- and ABA-microspheres was investigated depending on the qualitative and quantitative loading for three weeks. A 100-day value was determined additionally to estimate tendencies. In doing so, a dependency of the incorporated substance to the degradation behaviour of the polymer can be observed. Another part of this work deals with the production of a drug release system for use in ophthalmology. To treat proliferative vitreoretinopathy (PVR) a drug release system is required to prevent an undesired proliferation of retinal pigment epithel cells (RPE cells) on the retina. Ascorbic acid loaded PDLLA microspheres were made according to the o/w-solvent-evaporation method. These spheres were tested in an in vitro drug release experiment. Furthermore the incorporation of nanospheres into an e-PTFE foil covered stent for use in angioplasty is described in this work. Spherical nanoparticles made of poly(D,L lactide-co-TMC) (90:10) were designed in different size-distributions via the o/w solvent evaporation process. The nanosphere suspensions were pressed with pressure through an e-PTFE covered stent to obtain a foil loaded with nanoparticles. The release behaviour of the dexamethasone or paclitaxel loaded nanospheres incorporated in the stent was investigated in an in vitro experiment.","abstract_has_math":false,"creators":["Plum, Georg"],"institution":"Publikationsserver der RWTH Aachen University","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Höcker, Hartwig"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2004,"date_issued":"2004","date_published":"2004","updated_at":"2026-07-30T19:42:39Z","subjects":["info:eu-repo/classification/ddc/540","Chemie","Wirkstofffreisetzung","Mikrosphaeren","hydrophil","hydrophob","Kinetik"],"languages":["ger"],"rights":["info:eu-repo/semantics/openAccess"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-121353%22"],"render_values":[{"text":"https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-121353%22","href":"https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-121353%22","code":true}]}]},"links":{"outbound_url":"https://publications.rwth-aachen.de/record/59577","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Höcker, Hartwig"]},{"key":"dc:creator","label":"Author","values":["Plum, Georg"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:coverage","label":"Dc Coverage","values":["DE"]},{"key":"dc:date","label":"Dc Date","values":["2004"]},{"key":"dc:publisher","label":"Institution","values":["Publikationsserver der RWTH Aachen University"]},{"key":"dc:relation","label":"Dc Relation","values":["info:eu-repo/semantics/altIdentifier/urn/urn:nbn:de:hbz:82-opus-9053"]},{"key":"dc:type","label":"Dc Type","values":["info:eu-repo/semantics/doctoralThesis","info:eu-repo/semantics/publishedVersion"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["info:eu-repo/classification/ddc/540","Chemie","Wirkstofffreisetzung","Mikrosphaeren","hydrophil","hydrophob","Kinetik"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["ger"]},{"key":"dc:rights","label":"Dc Rights","values":["info:eu-repo/semantics/openAccess"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://publications.rwth-aachen.de/record/59577","https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-121353%22"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Within the scope of this dissertation, the release behaviour of different model substances and drugs from degradable poly-(D,L-lactide) (PDLLA) and poly-(D,L-lactide)-co-PEO-co-poly-(D,L-lactide) (ABA) microspheres as well as poly-(D,L-lactide-co-TMC)(90:10) nanospheres in PBS-buffer are characterised. To investigate the release behaviour, three different hydrophilic/hydrophobic benzophenone based model substances were chosen; 2,2’-dihydroxy-4,4’-dimethoxy-benzophenone-5,5’-disodium-sulfonate (Uvinul DS-49™), 2,2’,4,4’-tetrahydroxy-benzophenone (Uvinul D-50™) and 2-hydroxy-4-methoxy-benzophenone (Uvinul M-40™). The ABA-triblock copolymer was synthesized by ring opening polymerisation of lactide in the presence of polyethyleneoxide (PEO, 2000) as an initiator and tin(II)-2-ethylhexanoate as a catalyst. PDLLA and ABA-triblockcopolymer microspheres were made according to the o/w-solvent-evaporation method. The three model substances DS-49, D-50 and M-40 were incorporated with a theoretical loading of 9, 13 and 17 weight% respectively. The resultant microspheres were, depending on the particle size distribution, separated into two or three particle fractions in the range of 100-300µm, 300-710µm and if available 710-1000µm. The release behaviour was investigated depending on the particle size, the loading, the model substance and the polymeric matrix. Furthermore, the degradation behaviour of the 300-710µm ranged PDLLA- and ABA-microspheres was investigated depending on the qualitative and quantitative loading for three weeks. A 100-day value was determined additionally to estimate tendencies. In doing so, a dependency of the incorporated substance to the degradation behaviour of the polymer can be observed. Another part of this work deals with the production of a drug release system for use in ophthalmology. To treat proliferative vitreoretinopathy (PVR) a drug release system is required to prevent an undesired proliferation of retinal pigment epithel cells (RPE cells) on the retina. Ascorbic acid loaded PDLLA microspheres were made according to the o/w-solvent-evaporation method. These spheres were tested in an in vitro drug release experiment. Furthermore the incorporation of nanospheres into an e-PTFE foil covered stent for use in angioplasty is described in this work. Spherical nanoparticles made of poly(D,L lactide-co-TMC) (90:10) were designed in different size-distributions via the o/w solvent evaporation process. The nanosphere suspensions were pressed with pressure through an e-PTFE covered stent to obtain a foil loaded with nanoparticles. The release behaviour of the dexamethasone or paclitaxel loaded nanospheres incorporated in the stent was investigated in an in vitro experiment."]},{"key":"dc:source","label":"Dc Source","values":["Aachen : Publikationsserver der RWTH Aachen University XIV, 145 S. : Ill., graph. Darst. (2004). = Aachen, Techn. Hochsch., Diss., 2004"]},{"key":"dc:title","label":"Title","values":["Freisetzungsverhalten von unterschiedlich hydrophil/hydrophoben Modellsubstanzen aus Poly-(D,L-lactid)- und Poly-(D,L-lactid)-co-PEO-co-poly-(D,L-lactid)-Mikrosphären und pharmazeutische Anwendungen"]}]}],"canonical_facts":{"dc:contributor":["Höcker, Hartwig"],"dc:coverage":["DE"],"dc:creator":["Plum, Georg"],"dc:date":["2004"],"dc:description":["Within the scope of this dissertation, the release behaviour of different model substances and drugs from degradable poly-(D,L-lactide) (PDLLA) and poly-(D,L-lactide)-co-PEO-co-poly-(D,L-lactide) (ABA) microspheres as well as poly-(D,L-lactide-co-TMC)(90:10) nanospheres in PBS-buffer are characterised. To investigate the release behaviour, three different hydrophilic/hydrophobic benzophenone based model substances were chosen; 2,2’-dihydroxy-4,4’-dimethoxy-benzophenone-5,5’-disodium-sulfonate (Uvinul DS-49™), 2,2’,4,4’-tetrahydroxy-benzophenone (Uvinul D-50™) and 2-hydroxy-4-methoxy-benzophenone (Uvinul M-40™). The ABA-triblock copolymer was synthesized by ring opening polymerisation of lactide in the presence of polyethyleneoxide (PEO, 2000) as an initiator and tin(II)-2-ethylhexanoate as a catalyst. PDLLA and ABA-triblockcopolymer microspheres were made according to the o/w-solvent-evaporation method. The three model substances DS-49, D-50 and M-40 were incorporated with a theoretical loading of 9, 13 and 17 weight% respectively. The resultant microspheres were, depending on the particle size distribution, separated into two or three particle fractions in the range of 100-300µm, 300-710µm and if available 710-1000µm. The release behaviour was investigated depending on the particle size, the loading, the model substance and the polymeric matrix. Furthermore, the degradation behaviour of the 300-710µm ranged PDLLA- and ABA-microspheres was investigated depending on the qualitative and quantitative loading for three weeks. A 100-day value was determined additionally to estimate tendencies. In doing so, a dependency of the incorporated substance to the degradation behaviour of the polymer can be observed. Another part of this work deals with the production of a drug release system for use in ophthalmology. To treat proliferative vitreoretinopathy (PVR) a drug release system is required to prevent an undesired proliferation of retinal pigment epithel cells (RPE cells) on the retina. Ascorbic acid loaded PDLLA microspheres were made according to the o/w-solvent-evaporation method. These spheres were tested in an in vitro drug release experiment. Furthermore the incorporation of nanospheres into an e-PTFE foil covered stent for use in angioplasty is described in this work. Spherical nanoparticles made of poly(D,L lactide-co-TMC) (90:10) were designed in different size-distributions via the o/w solvent evaporation process. The nanosphere suspensions were pressed with pressure through an e-PTFE covered stent to obtain a foil loaded with nanoparticles. The release behaviour of the dexamethasone or paclitaxel loaded nanospheres incorporated in the stent was investigated in an in vitro experiment."],"dc:identifier":["https://publications.rwth-aachen.de/record/59577","https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-121353%22"],"dc:language":["ger"],"dc:publisher":["Publikationsserver der RWTH Aachen University"],"dc:relation":["info:eu-repo/semantics/altIdentifier/urn/urn:nbn:de:hbz:82-opus-9053"],"dc:rights":["info:eu-repo/semantics/openAccess"],"dc:source":["Aachen : Publikationsserver der RWTH Aachen University XIV, 145 S. : Ill., graph. Darst. (2004). = Aachen, Techn. 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