Myocardial liposome uptake in the early stages of myocardial infarction.

Multiply-labelled neutral or positively-charged liposomes were given iv to open-chested dogs or pigs 0.5 h or 5 h after coronary artery occlusion. Myocardial blood flow was measured by labelled microspheres. Animals were killed 3.5 h or 6 h after coronary artery occlusion and the myocardial distribution of liposomal labels was correlated with that of the microspheres. No evidence was found that liposomes are taken up preferentially by ischaemic myocardium. The results suggest that liposomes have limited potential as a means of drug delivery in myocardial infarction.