what is succinate
â¢ Succinate form of metoprolol is an extended release drug and it plays its role in the circulatory system for 24 hours. However, the tartrate form of metoprolol does not appear in the blood stream for 24 hours because metoprolol tartrate is an immediate-release drug. Succinate form of metoprolol is an extended release drug and it plays its role in the circulatory system for 24 hours. However, the tartrate form of metoprolol does not appear in the blood stream for 24 hours because metoprolol tartrate is an immediate-release drug.