Towards mitochondria-specific delivery of apoptosis-inducing agents: DQAsomal incorporated paclitaxel

DQAsomes have been developed by us as the first mitochondria-specific colloidal drug carrier system. Previously we have shown that DQA-somes meet all criteria for a mitochondria-targeted DNA delivery system. Here we describe for the first time the use of DQAsomes for encapsulating low-molecular weight compounds. As a model drug we have used paclitaxel, which has recently been shown to trigger apoptosis in tumor cells by acting directly on mitochondria. We demonstrate that paclitaxel can be incorporated into DQAsomes at an approximate ratio of 0.5 mol paclitaxel per mol dequalinium. Following an extensive physicochemical characterization of paclitaxel-loaded DQAsomes using three different electron microscopic techniques we tested in a preliminary study the ability of paclitaxel-loaded DQAsomes to inhibit the growth of human colon cancer cells in nude mice.