Chemsitry E-Learning package; Vinca Alkaloids, Etoposide, Pt compounds, Camptothecans etc

Question 1

How does Etoposide work?

Answer 1

Binds to topoisomerase II complex and so still leads to its inhibition (doesn’t intercalate with DNA tho)

Question 2

How do Platinum Compounds work?

Answer 2

Bind covalently to DNA via their platinum atom

Question 3

How do Camptothecans work?

Answer 3

Targets the complex between TP I and DNA

Question 4

What is the difference between camptothecan and topotecan?

Answer 4

Camptothecan is a natural product, whereas topotecan is a semi synthetic product that is clinically useful.

Question 5

What structural differences make topotecan clinically useful compared with camptothecan?

Answer 5

Topotecan is molecule A with additional groups at position 7, 9, 10, 11. The dimethylamino group in the sidechain will be protonated at physiological pH, increasing the polarity of the molecule and improving its water solubility, and so bioavailability. The hydroxyl group will also increase the polarity of the molecule.