Bioequivalence and Bioavailability Forum

Hi Mahesh M,

❝ – What is the steep exposure-response relationship?

It means that the slope of the dose-response curve is steep. Remember that sometimes we can describe the curve roughly with the Michaelis-Menten equation, and sometimes we opt to throw a Hill constant into the game. If a drug has a steep curve than some other drug it usually implies that it will have a higher Hill slope (Hill coefficient).
Steep is not a qualitative term. I cannot put a figure to it for the definition of such a drug. Everything is relative and vague. But I venture the opinion that the more pronounced the steepness, the higher the chance that a regulator would like to see monitoring of blood levels or other exposure indicators during therapy.

❝ – What is the difference between NTDI and steep exposure-response relationship?

If you have an NTDI with a relatively steep exposure-response relationship then a "little" deviation in terms of exposure (dose) could easier cause the effect to be outside the therapeutic window with everything that implies for safety/efficacy.

❝ – Literature reference regarding List of drugs which have steep exposure-response relationship

Can't help.