Structural Studies of Drug Delivery Systems

Ben Boyd and Chris Porter

The phase behaviour of lipid-based drug delivery systems may be a critical determinant of utility and impacts heavily on drug loading, stability and release. These complex systems are often characterised using Small Angle X-ray Scattering (SAXS) to identify particular phase structures and dimensions, and to probe the impact that drugs or other formulation variables may have on their structure and behaviour. The SAXS beamline proposed for the synchrotron will provide direct means of conducting rapid time kinetic experiments on these systems, leading to improved formulation approaches, and understanding of biological processing of oral lipid-based delivery systems.

Access to the SAXS beamline at the Australian Synchrotron would permit initial studies in this area such as:

• Kinetics of phase transitions in dispersed systems such as intestinal liposome to mixed micelle conversions, and their implications for drug delivery.
• Characterisation of dispersed liquid crystalline particles and the effects of formulation parameters on their utility.
• The influence of drug loading and other formulation parameters on mesophase structure.

Texture of reverse hexagonal phase of a lipid-based liquid crystalline system viewed through crossed polarising filters		Visual birefringence changes for a lipid-based lyotropic liquid crystalline system