Table IV.

Methods to Test Important Liposome Physical Properties

Test parameter/(relevance)	Analytical methods	Stress methods
Captured volume (encapsulation efficiency, release rate)	• Electron Spin Resonance (ESR) with CAT1 spin probe (volume exclusion method) (44) • Encapsulation of water soluble probe	Chemical degradation; heat, detergents, osmolarity change
Drug encapsulation (encapsulation efficiency, dose)	• Field flow fractionation • Filtration • Size exclusion chromatography • Sedimentation • Fluorescent probes • NMR probes	Chemical degradation; heat (phase transition temps), detergents, mechanical stress, sonication, osmolarity change
Liposome size (tissue targeting)	• Photon correlation spectroscopy (PCS) • Size exclusion chromatography • Field flow fractionation • Freeze fracture electron microscopy • Cryo-electron microscopy	Chemical degradation; heat, detergents, mechanical stress, sonication, osmolarity change, ionic milieu
Lamellarity (release rate)	• 31P NMR • PCS w/captured volume • Fluorescent probes • Chemical surface labeling	Chemical degradation; heat, detergents, mechanical stress, sonication
Surface charge (tissue targeting)	• Electrophoretic mobility	Chemical degradation; ionic milieu