Fate of methotrexate albumin microspheres after hepatic intra-arterial injection in dogs.

Methotrexate (MTX) albumin microspheres (40 microns) were injected into dog hepatic artery. The MTX levels in the hepatic vein maintained at relatively high concentration for over 3 h, whereas in the case of conventional MTX in saline the drug level decreased sharply soon after injection. After ia MTX in microspheres the MTX levels in liver were higher than those after MTX in saline. The microsphere emboli were entrapped in the hepatic precapillary arterioles. Thrombi were found in hepatic arterioles, with microsphere constituting the core. Hence MTX microspheres hepatic intra-arterial injection may be an effective treatment for patients with liver neoplasms.