This thesis examines the structural and kinetic properties of lipid-based drug delivery depots, with a particular focus on Camurus' FluidCrystal® injection technology. The aim is to enhance and the understanding of lipid depot formation, thereby contributing to the development of the drug delivery platform.

We investigated the phase behaviour of soybean phosphatidylcholine (SPC) and glycerol dioleate (GDO) mixtures, both in dry and hydrated states, using small-angle X-ray scattering (SAXS), revealing how lipid composition and water content influence the phase behaviour. Succeeding research explored the thermotropic behaviour of SPC, egg phosphatidylcholine (EPC), and dioleoylphosphatidylcholine (DOPC), highlighting the impact of lipid properties on structural transitions.

To understand lipid depot behaviour in aqueous environments, we studied the swelling kinetics using Karl Fischer titration and magnetic resonance imaging (MRI), which revealed the inhomogeneity at equilibrium. These findings were explored further by examining the hydration-induced lipid redistribution within lipid depots, employing techniques such as SAXS at synchrotron facilities and Raman spectroscopy. Lastly, the compatibility of FluidCrystal® formulations with hemp extract was assessed, demonstrating the system's robustness in incorporating active compounds.

These findings improve the understanding of lipid-based systems and support future research on formulations with active compounds and varied lipid compositions.