Abstract:
A method of preparing an anti-breast tumor compound comprised of a toxic metal bound to the blood protein transferrin is disclosed which has superior therapeutic properties. When monomeric transferrin is bound to cis-Dichlorodiammineplatinum (II), a chemotherapeutic agent is produced which specifically attacks and kills rapidly multiplying breast tumor cells without damaging normal cells. In addition, the body's immune defenses against foreign substances are substantially not activated. In preferred embodiments, 1. 8-2. 2 atoms of platinum are bound to each molecule of transferrin. The platinum-transferrin is prepared by first protecting the sulfhydro groups on essentially iron free transferrin with an excess of cystine in solution. Cis-dichlorodiammine platinum (II) is then reacted with the iron-free transferrin in the presence of bicarbonate anion. The platinum transferrin is dialyzed to remove the weak organic acid and bicarbonate anion, and then passed through molecular sieves to separate the monomeric product which is thereafter concentrated to a therapeutically useful concentration.