The present invention provides tricyclic compounds of Formula I:(see formula I)and pharmaceutically acceptable salts, solvates, or hydrates thereof, havingantimitotic activity,anti-multidrug resistance activity, for example P-glycoprotein inhibition, andantitumor activity,and which inhibit paclitaxel sensitive and resistant tumor cells. Thesecompounds are used fortreating tumor cells and inhibiting mitosis of cancerous cells.
