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Title: Multi functional polymers for drug delivery
Author: Alexander, Shirin
ISNI:       0000 0004 2734 6124
Awarding Body: University of Bristol
Current Institution: University of Bristol
Date of Award: 2012
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Amphiphilic block and graft copolymers have been studied because of the possibility of tailoring their complex and fascinating chemical properties. Potential applications include wetting agents, foaming agents, plastic modifiers as well as biomedical applications in drug delivery, owing to their biocompatible and low toxic nature. This thesis describes the study of a series of amphiphilic block copolymers, known as Pluronics, and their aqueous interaction with a hydrophobic drug, flurbiprofen. Synthesis and characterisation of novel graft copolymers with interesting associative behaviour that is less influenced by concentration is also another major aspect of the work described in this thesis. Pulsed-field gradient stimulated-echo nuclear magnetic resonance (pFGSE- NMR) and surface tension measurements have been used to show that the addition of flurbiprofen promotes micellisation of Pluronic triblock copolymers (PI03, P123, and L43). Structural changes in the micelles ofPluronics PI03 and P123, as a function of temperature, eo-solvent (ethanol, 10 wt/vol %), and the addition of the hydrophobic drug flurbiprofen were also investigated by small- angle neutron scattering (SANS). Flurbiprofen was shown to be released from micelles by increasing the solution pH. At higher pH, the drug is ionised and the fraction of polymer in micelles reduces. Synthesis of novel graft copolymers was carried out using a "grafting onto" method. In this approach, the functional group of a hydrophobic backbone will react with the functional group of the copolymer chains. The graft copolymers composed of either hydrophilic Pluronics or sulfonated poly(ethylene oxide) chains and hydrophobic backbones, displayed formation of core-shell micelles in selective solvents. The Pluronic graft copolymers showed the potential for solubilising hydrophobic drug molecules in aqueous solution even at low polymer concentrations. These graft copolymers and their interactions with flurbiprofen were characterised by PFGSE-NMR and SANS.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available