KINETIC MODELING OF LIPOSOME DEGRADATION IN PERITONEAL-MACROPHAGES

The objective of this study was to quantify and model the degradation process of liposomes in peritoneal macrophages (PMs). Iodinated albumi n (I-125-alb) was chosen to be the marker of liposome degradation. The time course of the degradation of free I-125- alb after pinocytosis b y PMs followed first-order kinetics with a half-life of 23 min. The de gradation of liposomally encapsulated I-125-alb was also quantified. K inetic modelling of liposome degradation indicated the existence of tw o kinetically different processes, one with a half-life of 13 min and the other with a half-life of 7.5 h. Comparing the degradation of lipo somal and free I-125-alb suggested that I-125-alb was delivered to lys osomes much faster through phagocytosis than pinocytosis. These result s indicate that the intracellular degradation kinetics of pinosomes an d phagosomes is different. This method can quantify the rate and exten t of liposomal degradation in macrophages and provide kinetic informat ion on the intracellular destiny of liposomally encapsulated compounds .