Preparation, Characterization, and Preliminary Application of Fibrinogen-Coated Olive Oil Droplets for the Targeted Delivery of Docetaxel to Solid Malignancies

Micronized droplets of olive oil loaded with docetaxel (1.0 mg·ml^-1) and coated with fibrinogen were prepared and then characterized for physicochemical and cytotoxic properties in vitro and anticancer activity in vivo. The droplets remain readily dispersible and relatively stable in size for at least 24 h when stored at 4°C. During storage, the fibrinogen remains bound to the droplets and thrombin coagulable. Nucleoside incorporation assays, growth inhibition assays, and clonogenic assays involving several different tumor cell lines all indicate that the cytotoxicity in vitro of docetaxel applied in olive oil droplets is at least as great as that of docetaxel applied in DMSO. When compared with Taxotere, an equivalent dose of docetaxel administered in fibrinogen-coated oil droplets improved the median survival time of B16F10 melanoma-bearing mice from 21 days to 69 days. Furthermore, whereas none of the Taxoteretreated mice survived longer than 34 days, 33% (three of nine) of the mice treated with docetaxel-loaded, fibrinogen-coated oil droplets were apparently free of disease after 139 days. Preliminary studies indicate fibrinogen adsorbed to docetaxel-loaded oil droplets facilitates the retention of the droplets within the fibrin-rich tumor microenvironment. We propose this new formulation may prove generally useful for the treatment of taxane-sensitive, fibrin-rich tumors.