Liposome shrinkage and swelling under osmotic-diffusional stress: evaluation of kinetic parameters from spectrophotometric measurements

Abstract

Analyses of spectrophotometric measurements of shrinkage and swelling of liposomes under osmotic-diffusional stress tacitly assume an 'empirical' inverse relationship between the absorbance (A) and the liposomal volume (ν). In this paper, we have proposed an alternate more explicit relationship: A=E_cLc αLr/1-Lr where L is liposomal concentration. E_c the extinction coefficient and α a dimensionless parameters. The exponential term, in essence, defines the partitioning of aqueous volume into intra- and extra-liposomal compartments. Experimental data obtained with glycerol as model compound are used to test the validity and internal consistency of the proposed formalism.