A targeted-modification study of choline and geranate (cage) analogues
File(s)
Author(s)
Dobre, Ana-Maria
Type
Thesis
Abstract
The use of ionic liquids in pharmaceutical applications, such as in the formulation and delivery of drugs, has garnered significant interest in recent years. One ionic liquid that has shown promise as a drug delivery agent is 1:2 choline and geranate (CAGE), which can improve the transdermal penetration of model drugs and can help stabilise proteins for oral delivery. An important first step in understanding the behaviour of 1:2 CAGE is identifying the underlying structure-property relationships, by studying systems with similar structures. This work presents a targeted-modification study in which three structural features that exist in 1:2 CAGE have been varied in order to understand their effect on the ionic liquid properties. Two cation species and four carboxylic acid species were employed and a total of six 1:2 ionic liquids were synthesised, including 1:2 CAGE. The thermal behaviour of these systems was analysed using differential scanning calorimetry and dynamic mechanical analysis, while their structuring was investigated using several different techniques, the most relevant being X-ray scattering. Almost all of the ionic liquids exhibited lamellar liquid crystalline mesophases, which collapse to an isotropic liquid structure when heated. The stability of these mesophases is heavily influenced by the nature of the species present in the system. Generally, linear, saturated anions led to a more stable liquid crystalline mesophase, while the presence of a hydroxyl group on the cation was found to further stabilise this structure. However, these observations do not hold true for all systems. Some of the ionic liquids in this work show the coexistence of multiple liquid crystalline mesophases within their structure. Often, but not always, these additional mesophases have a lamellar bilayer structure; in some cases, however, their geometry remains undetermined.
Version
Open Access
Date Issued
2024-07-04
Date Awarded
01/02/2025
License URL
Advisor
Welton, Tom
Brooks, Nick
Sponsor
Engineering and Physical Sciences Research Council
GlaxoSmithKline
Publisher Department
Department of Chemistry
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)