Volumetric Studies Of Lecithin-Water Dispersions
| dc.contributor.author | Yeap, Pei Koon | |
| dc.date.accessioned | 2016-11-24T01:23:20Z | |
| dc.date.available | 2016-11-24T01:23:20Z | |
| dc.date.issued | 2007-03 | |
| dc.description.abstract | Volumetric studies of lecithin-water dispersions were carried out. A literature review of liposomes and their applications in various areas of science and medicine was presented to illustrate the importance of research studies on liposomes. The main objectives of this present study are to determine accurately the density of the lecithin dispersions and the density of the lecithin in the dispersions, as well as to elucidate the molecular packing structure of the liposomes in the lecithin dispersions. To achieve this aim, sizes of liposomes were estimated via turbidity measurements, while the density of the lecithin dispersions were determined accurately over a temperature range from 25 °C to 55°C using a digital density meter. Further studies on the effects of ions were similarly investigated. The estimation of the liposome sizes in different lecithin dispersions supported the observation that prolonged sonication typically produced small unilamellar liposomes. The density of the lecithin in the dispersions was calculated and the value was found to be comparable to the value in the dry state (1.056 g cm-\ Nevertheless, the value was found to be slightly higher for dispersions with higher concentrations of lecithin. This observation was further confirmed by the calculated values of the effective molecular volume of lecithin, which were smaller for higher concentrations of lecithin in the dispersions. Temperature dependence studies of density demonstrated the presence of a thermotropic phase transition at about 40°C to 45 DC. With the addition of Ca2+ ions or Na+ ions to the lecithin dispersions, the density of the lecithin dispersions and the density of the lecithin in the dispersions increased. However, the effective molecular volume of lecithin in the dispersions decreased. The above effects were more pronounced with the addition of Ca2+ ions compared to the addition of Na+ ions, thus probably indicating that Ca2+ ions pack the lecithin molecules in the dispersions even tighter when compared to that of Na+ ions. | en_US |
| dc.identifier.uri | http://hdl.handle.net/123456789/3174 | |
| dc.subject | To determine accurately the density of the lecithin dispersions | en_US |
| dc.subject | and the density of the lecithin in the dispersions | en_US |
| dc.title | Volumetric Studies Of Lecithin-Water Dispersions | en_US |
| dc.type | Thesis | en_US |
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