Narrow Band Dielectrometry as a Tool to Monitor Drug Release and Accumulation in Liposomes

The method of microwave dielectrometry was used to measure the dielectric parameters of aqueous liposome suspensions. Based upon measurements of complex dielectric permittivity at a single frequency in the range of bulk water dispersion we were able to estimate hydration of lipid vesicles. It was shown that the magnitude of hydration calculated from the increment of static dielectric permittivity could be used to monitor loading of liposomes with antimicrobial peptide and to track the release of drug from nano-carriers. Redistribution of free and bound water in liposome suspensions upon binding and dissociation of small molecules with lipid membranes of nano-sized spherical particles, precisely traced by dielectric measurements at microwaves, can be used as a diagnostic tool in targeted drug delivery technologies for quality control and monitoring of cargo loading and unloading.