Amlodipine Besylate, Is This A Time Release Version Of Norvasc?

Amlodipine Besylate, is this a time release version of Norvasc? I ask this because every morning around 4:00am I'm having a strong attack or major distress in my chest near the sternum - which radiates into my back. After a few hours it lets up a little. I sincerely believe a time released factor may be happening & is causing this. Is there a Norvasc med without Besylate included in its formula?