He, Liang;
(2007)
Thermodynamic studies of hydrogel swelling and interaction with drugs.
Doctoral thesis (Ph.D.), University College London (United Kingdom).
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Abstract
Hydrogels have attracted great attention because of their excellent potential in application in the area of pharmaceutical research. This study mainly focused on the mechanism of swelling and the interaction of hydrogels with drugs by dissolution and calorimetry methods. In this work, pH-sensitive hydrogels-poly (methacrylic acid) PMAA were synthesized. By the dissolution method, the effect of pH on swelling was investigated. A series of temperature dependent poly (ethylene glycol) (PEG) hydrogels were synthesized and were characterized by the temperature dependence of their degree of equilibrium swelling in aqueous media. The dynamic swelling behaviour of these PEG hydrogels were investigated to determine the mechanism of water transport. The interaction between hydrogel and drugs also has been investigated by using metronadizole, diclofenac, and salicylic acid as model drugs. In this study, the use of solution microcalorimetry as an investigational tool for hydrogels was assessed. Starting with simple swelling, hydrogels were introduced into solution microcalorimeter and the power-time data recorded. It was noted that the response of the PEG1500 hydrogel was clearly biphasic while that of PEG400 was monophasic. The interaction with drugs was then investigated using three model drugs; metronidazole, diclofenac sodium and salicylic acid. Salicylic acid showed a significant exothermic heat of interaction, while diclofenac sodium and metronidazole showed small heats of interaction. PMAA also have been investigated by solution microcalorimetry and the results showed that solution microcalorimetry possessed the ability to investigate the pH sensitive swelling mechanism. Isothermal titration micocalorimetry (ITM) provided the direct enthalpy of the interactions between solutes and hydrogels during diffusion. Heats of interaction varied in magnitude; salicylic acid > diclofenac sodium > metronidazole. Since calorimetry-solution microcalorimetry and ITM have demonstrated to be useful to investigate the hydrogels, general conclusion have been summarized and prediction about more complicated system based on the knowledge acquired in this work was envisioned in the end of this thesis.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D. |
| Title: | Thermodynamic studies of hydrogel swelling and interaction with drugs |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Thesis digitised by ProQuest. |
| Keywords: | (UMI)AAI10105156; Health and environmental sciences; Drugs; Hydrogel; Swelling; Thermodynamic |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10104979 |
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