2017 年 40 巻 2 号 p. 119-127
Liposomes have been widely used as drug carriers in the field of drug delivery systems (DDS), and they are thought to be ideal nano-capsules for targeting DDS after being injected into the bloodstream. In general, DDS drugs meet the needs of aged and super-aged societies, since the administration route of drugs can be changed, the medication frequency reduced, the adverse effects of drugs suppressed, and so on. In fact, a number of liposomal drugs have been launched and used worldwide including liposomal anticancer drugs, and these drugs have appeared on the market owing to various innovations in liposomal DDS technologies. The accumulation of long-circulating liposomes in cancer tissue is driven by the enhanced permeability and retention (EPR) effect. In this review, liposome-based targeting DDS for cancer therapy is briefly discussed. Since cancer angiogenic vessels are the ideal target of drug carriers after their injection and are critical for cancer growth, damaging of these neovessels has been an approach for eradicating cancer cells. Also, the usage of liposomal DDS for the treatment of ischemic stroke is possible, since we observed that PEGylated liposomes accumulate in the site of cerebral ischemia in transient middle cerebral artery occlusion (t-MCAO) model rats. Interestingly, liposomes carrying neuroprotectants partly suppress ischemia/reperfusion injury of these model rats, suggesting that the EPR effect also works in ischemic diseases by causing an increase in the permeability of the blood vessel endothelium. The potential of liposomal DDS against life-threatening diseases might thus be attractive for supporting long-lived societies.
